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发布于：2004-10-28 15:57

美国FGDC 元数据标准除在美国国内广泛使用外，加拿大、印度等国也已等同采用，作为各自的国家标准。ISO/TC 211利用该标准文本作为基础，正在制定相应的国际标准。 <H4 0cm; TEXT-INDENT: 0cm"><A>2.2.2 美国FGDC</A>的元数据标准实例</H4>Metadata for 1-degree Digital Elevation ModelsThese metadata describe the 1-degree digital elevation model holdings of the USGS for the conterminous United States. This is a data-set level implementation of the Content Standards for Digital Geospatial Metadata, and will be in place until file-specific information for individual digitalelevation models is available. Table of Contents <UL type=disc><LI class=MsoNormal style="tab-stops: list 36.0pt; mso-list: l60 level1 lfo46; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto">Identification_Information <LI class=MsoNormal style="tab-stops: list 36.0pt; mso-list: l60 level1 lfo46; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto">Data_Quality_Information <LI class=MsoNormal style="tab-stops: list 36.0pt; mso-list: l60 level1 lfo46; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto">Spatial_Data_Organization_Information <LI class=MsoNormal style="tab-stops: list 36.0pt; mso-list: l60 level1 lfo46; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto">Spatial_Reference_Information <LI class=MsoNormal style="tab-stops: list 36.0pt; mso-list: l60 level1 lfo46; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto">Entity_and_Attribute_Information <LI class=MsoNormal style="tab-stops: list 36.0pt; mso-list: l60 level1 lfo46; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto">Distribution_Information <LI class=MsoNormal style="tab-stops: list 36.0pt; mso-list: l60 level1 lfo46; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto">Metadata_Reference_Information </LI></UL>Identification_Information: Citation:Citation_Information:Originator: Defense Mapping AgencyPublication_Date: unknownTitle: 1-degree Digital Elevation ModelsGeospatial_Data_Presentation_Form: mapPublication_Information:Publication_Place: Reston, VAPublisher: U. S. Geological SurveyDescription:Abstract:Digital Elevation Model (DEM) is the terminology adopted by the USGS to describe terrain elevation data sets in a digital raster form. The standard DEM consists of a regular array ofelevations cast on a designated coordinate projection system. The DEM data are stored as a series of profiles in which the spacing of the elevations along and between each profile is in regular whole number intervals. The normal orientation of data is by columns and rows. Each column contains a series of elevations ordered from south to north with the order of the columns from west to east. The DEM is formatted as one ASCII header record (A-record), followed by a series of profile records (B-records) each of which include a short B-record header followed by a series of ASCII integer elevations per each profile. The last physical record of the DEM is an accuracyrecord (C-record). 1-degree DEM (3- by 3-arc second data spacing). Provides coverage in 1- by 1-degree blocks. Two products (three in some regions of Alaska) provide the same coverage as a standard USGS 1- by 2-degree quadrangle. The basic elevation model is produced by or for the Defense Mapping Agency (DMA), but is distributed by the USGS in the DEM data record format. Coverage is for the United States.Purpose:DEM's can be used as source data for digital orthophotos, and, as layers in geographic information systems, for earth science analysis. DEM's can also serve as tools for volumetric analysis, for site location of towers, or for drainage basin delineation.Supplemental_Information:1-degree DEM's have rows and columns which are based on the geographic coordinate system. The use of this system results in a rectangular DEM which shares a common edge and thereforeduplicate points with other adjacent 1-degree DEM's.Time_Period_of_Content:Time_Period_Information:Range_of_Dates/Times:Beginning_Date: 19791000Ending_Date: 19900331Currentness_Reference: ground conditionStatus:Progress: completeMaintenance_and_Update_Frequency: IrregularSpatial_Domain:Bounding_Coordinates:West_Bounding_Coordinate: -124.7333East_Bounding_Coordinate: -067.9500North_Bounding_Coordinate: 49.3833South_Bounding_Coordinate: 24.5333Keywords:Theme:Theme_Keyword_Thesaurus: noneTheme_Keyword: DEMTheme_Keyword: digital elevation modelTheme_Keyword: digital terrain modelTheme_Keyword: hypsographyTheme_Keyword: altitudeTheme_Keyword: heightTheme_Keyword: contour lineTheme_Keyword: digital contoursAccess_Constraints: NoneUse_Constraints:None. Acknowledgement of the U.S. Geological Survey would be appreciated in products derived from these data.Data_Quality_InformationAttribute_Accuracy:Attribute_Accuracy_Report:The accuracy of a DEM is dependent upon the level of detail of the source and the grid spacing used to sample that source. The primary limiting factor for the level of detail of the source is the scale of the source materials. The proper selection of grid spacing determines the level of content that may be extracted from a given source during digitization.Logical_Consistency_Report:The fidelity of the relationships encoded in the data structure of the DEM are automatically verified using a USGS software program upon completion of the data production cycle. The test verifies full compliance to the DEM specificationCompleteness_Report:The DEM is visually inspected for completeness on a DEM view and edit system for the purpose of performing a final quality control and if necessary edit of the DEM. The physical formatof each digital elevation model is validated for content completeness and logical consistency during production quality control and prior to archiving in the National Digital Cartographic Data Base.Level 2 DEM: Level 2 DEM's may contain void areas due to interruptions to contours in the source graphic or DLG. Void area elevation grid posts are assigned the value of -32,767. In addition, suspect elevation areas may exist in the DEM but are not specifically identified. Suspect areas can be located on the source graphic as a "disturbed surface" which are symbolized by contours overprinted with photorevised or other surface patterns.Positional_Accuracy:Horizontal_Positional_Accuracy:Horizontal_Positional_Accuracy_Report:Digital elevation models meet horizontal National Map Accuracy Standards (NMAS) accuracy requirements. NMAS horizontal accuracy requires that at least 90 percent of points tested are within 0.02 inches of the true position. The primary reference from which 1-degree DEM accuracy is derived is source-based, as a minimum, meeting NMAS for100,000-scale USGS topographic series maps.Quantitative_Horizontal_Positional_Accuracy_Assessment:Horizontal_Positional_Accuracy_Value:RMSE of the DEM. The 1-degree DEM accuracy is source-dependent and is based on the 1:100,000-scale USGS topographic series map. Horizontal_Positional_Accuracy_Explanation:Digital elevation models meet horizontal National Map Accuracy Standards (NMAS) accuracy requirements.Vertical_Positional_Accuracy:Vertical_Positional_Accuracy_Report:The vertical root-mean-square error (RMSE) statistic is used to describe the vertical accuracy of a DEM, encompassing both random and systematic errors introduced during production of the data. The RMSE is encoded in element number 5 of record C of the DEM. Accuracy is computed by a comparison of linear interpolated elevations in the DEM with corresponding known elevations. Test points are well distributed, representative of the terrain, and have true levations with accuracies well within the DEM accuracy criteria. Acceptable test points include, in order of preference: field control, aerotriangulated test points, spot elevations, or points on contours from existing source maps with appropriate contour interval. A minimum of 28 test points per DEM is required to compute the RMSE, which is composed of a single test using 20 interior points and 8 edge points. Edge points are those which are located along, at, or near the quadrangle neatlines and are deemed by the editor to be useful to evaluating the accuracy of the edge of the DEM. Collection of test point data and comparison of the DEM with the quadrangle hypsography are conducted by the quality control units within the USGS. There are three types of DEM vertical error; blunder, systematic and random. These errors are reduced in magnitude by editing but cannot be completely eliminated and may be encountered. Blunder errors are those errors of major proportions and are easily identified and removed during interactive editing. Systematic errors are those errors that follow some fixed pattern and are introduced by data collection procedures and systems. These error artifacts include: vertical elevation shifts, misinterpretation of terrain surface due to trees, buildings and shadows, and fictitious ridges, tops, benches or striations. Random errors result from unknown or accidental causes. DEMs are edited to correctly depict elevation surfaces that correspond to water bodies of specified size.Level 2 DEM: A vertical RMSE of one-half of the contour interval (of 100,000-scale source), determined by the source map, is the maximum permitted. Systematic errors may not exceed one contour interval, determined by the source map, is the maximum permitted. Systematic errors may not exceed one contour interval specified by the source graphic. Level 2 DEM's have been processed or smoothed for consistency and edited to remove identifiable systematic errors.Quantitative_Vertical_Positional_Accuracy_Assessment:Vertical_Positional_Accuracy_Value: RMSEVertical_Positional_Accuracy_Explanation:Lineage:Source_Information:Source_Citation:Citation_Information:Originator: U.S. Geological SurveyPublication_Date:Title: digital contour linesGeospatial_Data_Presentation_Form: mapPublication_Information:Publication_Place: Reston, VAPublisher: U.S. Geological SurveyType_of_Source_Media: magnetic tapeSource_Time_Period_of_Content:Time_Period_Information:Range_of_Dates/Times:Beginning_Date: variousEnding_Date: variousSource_Currentness_Reference:bbbSource_Citation_Abbreviation: CONTOUR1Source_Contribution:Hypsographic vector information which is interpolated to regular grid posts to form DEM grids in 3- by 3-arc second data spacing within the 1-degree DEM bounds.Source_Information:Source_Citation:Citation_Information:Originator: U.S. Geological SurveyPublication_Date:Title: digital elevation modelGeospatial_Data_Presentation_Form: mapPublication_Information:Publication_Place: Reston, VAPublisher: U.S. Geological Survey

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发布于：2004-10-28 15:57

Type_of_Source_Media: magnetic tapeSource_Time_Period_of_Content:Time_Period_Information:Range_of_Dates/Times:Beginning_Date: variousEnding_Date: variousSource_Currentness_Reference: ground conditionSource_Citation_Abbreviation: DEM1Source_Contribution:Elevation data in the form of a digital elevation model regridded to 3- by 3-arc second data spacing within the 1-degree DEM bounds.Process_Step:Process_Description:DEM's are created by gridding digital line graph (DLG) contours or the equivalent from USGS 1:24,000-scale or 1:100,000-scale maps. DEM's may also be created from regridding 7.5-minute DEMs to the coarser 3-arc second grid spacing of the 1-degree DEM. The accuracy and data spacing are intended to support computer applications that analyze hypsographic features to a level of detail similar to manual interpolation of information from printed source maps. Quality control: DEM's are viewed on interactive editing systems to identify and correct blunder and systematic errors. DEM's are verified for physical format and logical consistency at the production centers and before archiving in the National Digital Cartographic Data Base (NDCDB) utilizing the Digital Elevation Model Verification System (DVS) software. Additional information on this software may be found in Department of the Interior, U.S. Geological Survey, 1993, Technical Instructions, DVS Users Manual (draft): Reston, VASource_Used_Citation_Abbreviation: CONTOUR1, DEM1Process_Date:Spatial_Data_Organization_InformationDirect_Spatial_Reference_Method: rasterRaster_Object_Information:Raster_Object_Type: grid cellRow_Count: 1201Column_Count: 1201Spatial_Reference_Information:Horizontal_Coordinate_System_Definition:Geographic:Latitude_Resolution: 3Longitude_Resolution: 3Geographic_Coordinate_Units: Decimal secondsVertical_Coordinate_System_Definition:Altitude_System_Definition:Altitude_Datum_Name: National Geodetic Vertical Datum of 1929Altitude_Resolution: 1Altitude_Distance_Units: metersAltitude_Encoding_Method:Explicit elevation coordinate included with horizontal coordinatesEntity_and_Attribute_Information: Overview_Description:Entity_and_Attribute_Overview:The digital elevation model is composed of a 6-character integer raster representing a gridded form of a topographic map hypsography overlay. Each raster entity contains a 6-character integer value between -32,767 and 32,768. Entity_and_Attribute_Detail_Citation:U.S. Department of the Interior, U.S. Geological Survey, 1992,Standards for digital elevation models: Reston, VAA hypertext version is available at:<URL: ftp://www-nmd.usgs.gov/pub/dem_html/standards_dem.html>A hypertext extract is available at:<URL: http://edcwww.cr.usgs.gov/glis/hyper/guide/1_dgr_dem>Softcopy in ASCII format is available at:<URL: ftp://www-nmd.usgs.gov/pub/ti/DEM/demstnds/stdempt1.txt><URL: ftp://www-nmd.usgs.gov/pub/ti/DEM/demstnds/stdempt2.txt><URL: ftp://www-nmd.usgs.gov/pub/ti/DEM/demstnds/stdempt3.txt>Softcopy in WordPerfect format is available at:<URL: ftp://www-nmd.usgs.gov/pub/ti/DEM/demstnds/stdempt1.wp5><URL: ftp://www-nmd.usgs.gov/pub/ti/DEM/demstnds/stdempt2.wp5><URL: ftp://www-nmd.usgs.gov/pub/ti/DEM/demstnds/stdempt3.wp5>Softcopy in PostScript format is available at:<URL: ftp://www-nmd.usgs.gov/pub/ti/DEM/demstnds/stdempt1.ps><URL: ftp://www-nmd.usgs.gov/pub/ti/DEM/demstnds/stdempt2.ps><URL: ftp://www-nmd.usgs.gov/pub/ti/DEM/demstnds/stdempt3.ps>Distribution_Information: Distributor:Contact_Information:Contact_Organization_Primary:Contact_Organization: Earth Science Information Center, U.S. Geological SurveyContact_Address:Address_Type: mailing and physical addressAddress: 507 National CenterCity: RestonState_or_Province: VirginiaPostal_Code: 22092Contact_Voice_Telephone: 1 800 USA MAPSHours_of_Service: 0800-1600Contact_Instructions:In addition to the address above there are other ESIC offices throughout the country. A full list of these offices is at: <URL: http://www-nmd.usgs.gov/esic/esic_index.html>Resource_Description: 1-degree digital elevation modelsDistribution_Liability:Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made by the Geological Surveyregarding the utility of the data on any other system, nor shall the act of distribution constitute any such warranty. The USGS will warrant the delivery of this product in computer-readable format and will offer appropriate adjustment of credit when the product is determined unreadable bycorrectly adjusted computer input peripherals, or when the physical medium is delivered in damaged condition. Requests for adjustments of credit must be made within 90 days fromthe date of this shipment from the ordering site. Standard_Order_Process:Digital_Form:Digital_Transfer_Information:Format_Name: DEMFormat_Information_Content:The standard USGS DEM can be described as an ASCII formatted elevation file preceded by a metadata header file which consists of one 1024-byte ACSII record. Transfer_size: 1.4 (per 15-minute DEM unit)Digital_Transfer_Option:Online_Option:Computer_Contact_Information:Network_Address:Network_Resource_Name:<URL: http://edcwww.cr.usgs.gov/glis/hyper/guide/1_dgr_demfig/index1m.html>Online_Option:Computer_Contact_Information:Network_Address:Network_Resource_Name: <URL: http://edcwww.cr.usgs.gov/glis/hyper/guide/1_dgr_demfig/states.html>Online_Option:Computer_Contact_Information:Network_Address:Network_Resource_Name: <URL:ftp://edcftp.cr.usgs.gov/pub/data/DEM/250/Offline_Option:Offline_Media: 9-track tapeRecording_Format:standard 9-track label, record length 1024. To ensure compatibility, a maximum blocking factor (specified in multiples of 1024) of 31744 is recommended. For efficiency, blocking factors less than 16,000 are discouraged.Compatibility_Information: NoneFees:The online copy of the data set (when available electronically) may be accessed without charge. For 8-mm cartridge and 9-track tapes the costs are:1 digital product = $402 digital products = $603 digital products = $804 digital products = $1005 digital products = $1206 or more = $90 plus $7 per each product over six A $3.50 handling charge is applied to all mail orders.Metadata_Reference_Information: Metadata_Date: 199501Metadata_Contact:Contact_Information:Contact_Organization_Primary:Contact_Organization: U.S. Geological SurveyContact_Address:Address_Type: mailing addressAddress: 508 National CenterCity: RestonState_or_Province: VAPostal_Code: 22092Contact_Voice_Telephone: 703 648 4543Metadata_Standard_Name: Content Standards for Digital Geospatial MetadataMetadata_Standard_Version: 19940608USGS Node of NSDI Clearinghouse home page This page is <http://nsdi.usgs.gov/nsdi/maps/dem1deg.HTML>. This page is maintained by <nsdi@usgs.gov> Last modified: 14AUG95

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发布于：2004-10-28 15:57

<H3 0cm; TEXT-INDENT: 0cm"><A>2.3 国际上其他元数据标准简介</A></H3>对于元数据标准内容，目前国际上主要有三个组织作了大量的工作，它们分别是欧洲标准化组织（CEN/TC 287）、美国联邦地理数据委员会（FGDC）以及国际标准化组织（ISO/TC 211）。下面我们对这三个组织的元数据内容分别作一讨论。　表3.1 元数据内容组成<DIV align=center><TABLE 523.5pt; mso-cellspacing: .7pt; mso-padding-alt: 6.75pt 6.75pt 6.75pt 6.75pt" cellSpacing=1 cellPadding=0 width=698 border=1><TR 1.05pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 23%; PADDING-TOP: 6.75pt; HEIGHT: 1.05pt" vAlign=top width="23%">CEN/TC 287</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 1.05pt" vAlign=top width="26%">FGDC</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 1.05pt" vAlign=top width="26%">ISO/TC 211</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 1.05pt" vAlign=top width="26%">本文建议的标准草案</TD></TR><TR 0.65pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 23%; PADDING-TOP: 6.75pt; HEIGHT: 0.65pt" vAlign=top width="23%">数据集标识信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 0.65pt" vAlign=top width="26%">标识信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 0.65pt" vAlign=top width="26%">标识信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 0.65pt" vAlign=top width="26%">标识信息</TD></TR><TR 13.9pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 23%; PADDING-TOP: 6.75pt; HEIGHT: 13.9pt" vAlign=top width="23%">数据集综述信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 13.9pt" vAlign=top width="26%">数据质量信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 13.9pt" vAlign=top width="26%">数据质量信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 13.9pt" vAlign=top width="26%">数据质量信息</TD></TR><TR 10.8pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 23%; PADDING-TOP: 6.75pt; HEIGHT: 10.8pt" vAlign=top width="23%">数据集质量元素</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 10.8pt" vAlign=top width="26%">空间数据组织信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 10.8pt" vAlign=top width="26%">数据集继承信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 10.8pt" vAlign=top width="26%">数据集继承信息</TD></TR><TR 7.6pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 23%; PADDING-TOP: 6.75pt; HEIGHT: 7.6pt" vAlign=top width="23%">空间参照系信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 7.6pt" vAlign=top width="26%">空间参照系信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 7.6pt" vAlign=top width="26%">空间数据表示信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 7.6pt" vAlign=top width="26%">空间数据表示信息</TD></TR><TR 15pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 23%; PADDING-TOP: 6.75pt; HEIGHT: 15pt" vAlign=top width="23%">范围信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 15pt" vAlign=top width="26%">实体和属性信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 15pt" vAlign=top width="26%">空间参照系信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 15pt" vAlign=top width="26%">空间参照系信息</TD></TR><TR 11.2pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 23%; PADDING-TOP: 6.75pt; HEIGHT: 11.2pt" vAlign=top width="23%">数据定义</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 11.2pt" vAlign=top width="26%">发行信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 11.2pt" vAlign=top width="26%">应用要素分类信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 11.2pt" vAlign=top width="26%">实体和属性信息</TD></TR><TR 8.8pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 23%; PADDING-TOP: 6.75pt; HEIGHT: 8.8pt" vAlign=top width="23%">分类信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 8.8pt" vAlign=top width="26%">元数据参考信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 8.8pt" vAlign=top width="26%">发行信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 8.8pt" vAlign=top width="26%">发行信息</TD></TR><TR 6.4pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 23%; PADDING-TOP: 6.75pt; HEIGHT: 6.4pt" vAlign=top width="23%">管理信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 6.4pt" vAlign=top width="26%"> </TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 6.4pt" vAlign=top width="26%">元数据参考信息</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 6.4pt" vAlign=top width="26%">元数据参考信息</TD></TR><TR 10.15pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 23%; PADDING-TOP: 6.75pt; HEIGHT: 10.15pt" vAlign=top width="23%">元数据参考</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 10.15pt" vAlign=top width="26%"> </TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 10.15pt" vAlign=top width="26%"> </TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 10.15pt" vAlign=top width="26%"> </TD></TR><TR 7.05pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 23%; PADDING-TOP: 6.75pt; HEIGHT: 7.05pt" vAlign=top width="23%">元数据语言</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 7.05pt" vAlign=top width="26%"> </TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 7.05pt" vAlign=top width="26%"> </TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 26%; PADDING-TOP: 6.75pt; HEIGHT: 7.05pt" vAlign=top width="26%"> </TD></TR></TABLE></DIV> <H4 0cm; TEXT-INDENT: 0cm"><A>2.3.1 CEN/TC 287</A></H4>CEN/TC 287是从事元数据研究比较早的单位[CEN/TC286 Secretariat,1996]。早在1992年，该委员会就开始了有关数字地理信息标准化方面的工作，并成立了四个工作组，从地理信息标准化框架（WG 1）、地理信息模型和应用（WG 2）、地理信息传输（WG 3）、以及地理信息定位参考系统（WG 4）等方面开始标准的制定工作。它的目的是想通过建立一系列结构化标准，以确定一种用于定义、描述、传输、以及表示现实世界的标准方法，促使与地理位置有关的数字信息的使用。CEN/TC 287成立后，通过会议等方式很快建立了一系列标准草案，并通过14个工作组开展工作(第4和第12工作组空缺)，其中元数据研究属于第2工作组中第9工作小组，即287009。在CEN/TC 287中，把元数据分为标识信息、数据集综述信息、数据集质量元素、空间参照系信息、范围信息、数据定义、分类信息、管理信息、元数据参考、以及元数据语言等10个部分来描述数据集，每一部分又有各自的组成元素。表3.2 CEN/TC 287的标准工作组<DIV align=center><TABLE 461.25pt; mso-cellspacing: .7pt; mso-padding-alt: 6.75pt 6.75pt 6.75pt 6.75pt" cellSpacing=1 cellPadding=0 width=615 border=1><TR 65.8pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 47%; PADDING-TOP: 6.75pt; HEIGHT: 65.8pt" vAlign=top width="47%">WG 1：地理信息标准化框架</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 53%; PADDING-TOP: 6.75pt; HEIGHT: 65.8pt" vAlign=top width="53%">287001 参考模型287002 综述287003 定义287005 数据描述技术287013 查询与更新</TD></TR><TR 6pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 47%; PADDING-TOP: 6.75pt; HEIGHT: 6pt" vAlign=top width="47%">WG 2：地理信息模型和应用</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 53%; PADDING-TOP: 6.75pt; HEIGHT: 6pt" vAlign=top width="53%">287006 应用模式规则287007 空间模式287008 质量287009 元数据</TD></TR><TR 17.25pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 47%; PADDING-TOP: 6.75pt; HEIGHT: 17.25pt" vAlign=top width="47%">WG 3：地理信息传输</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 53%; PADDING-TOP: 6.75pt; HEIGHT: 17.25pt" vAlign=top width="53%">287010 传输</TD></TR><TR 17.25pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 47%; PADDING-TOP: 6.75pt; HEIGHT: 17.25pt" vAlign=top width="47%">WG 4：地理信息定位参考系统</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 53%; PADDING-TOP: 6.75pt; HEIGHT: 17.25pt" vAlign=top width="53%">287011 位置287014 间接定位系统</TD></TR></TABLE></DIV> <H4 0cm; TEXT-INDENT: 0cm"><A>2.3.2 电器和电子工程师协会 (IEEE)</A></H4>电器和电子工程师协会 (IEEE) 在1994年2月的白皮书中指出：元数据是关于数据的信息，它使得有效地管理和访问数据成为可能。该协会认为至少有两种元数据，即系统级元数据和应用级元数据。前者是用于管理数据的信息，包括数据访问时间、数据量、当前的存储位置等；后者是帮助用户的信息，包括找到、评价、访问和使用数据的信息。在某些情况下，访问元数据应当比访问数据快。为此，要求将元数据常驻在较高等级的设备上。在处理特大型数据集时这一点特别重要。元数据的内容是没有限定的。一般而言，元数据可以是文件系统或应用所需要的任何信息。它应当是可扩充的。元数据的量也是没有限定的。但是，它总是比其说明的对象，即数据的量小。元数据的大小取决于访问的复杂性，或管理水平的要求。元数据的主要目的是解决数据管理和共享问题。元数据能够改进系统有效存储、检索和移动数据的能力。当今生产和储存的大量数据对于用户是严重的挑战。如果用户无法知道有什么数据和在哪儿能找到它们，就无法使用它们。用户对这些大型数据集的应用能
力取决于对数据有效地访问及管理能力。为解决这些数据管理和共享方面的问题，许多部门已经在其系统上建立了元数据库。以便用户能够通过元数据快速浏览数据，并决定是否值得检索数据。例如，用户对一幅特定的地图感性趣，但是，要检索该幅图需要若干小时，而一幅比较小的、较低分辨率的
地图已经够用。如果向用户提供关于地图分辨率的元数据，用户就能够作出有关检索数据的正确决定。IEEE从1993年以来召开了一系列以理解和定义“元数据”或数据访问问题为主题的学术讨论会。1993年8月26－27日在美国召开的第一次元数据学术讨论会目的为： 用任何形式访问储存在任何地方的大型数据库； 有效地、容易地管理大型数据库； 易于在不同类型的单位和系统间交换数据； 定义抽象的数据类型和结构。 这次讨论会一致通过的元数据定义为：元数据是有关存储数据实体的信息，包括语义和信息内容、元素类型和编码、实体之间的关系、数据结构、数据格式、数据类型、相关的数据、数据推论和派生等；元数据是有关数据存储管理的信息，包括位置和名称、访问时间、访问方法等；元数据也是有关数
据应用的信息，包括使用限制、使用方法、历史记录等。元数据分为两个等级：概要的元数据适用于所有数据文件、详细的元数据适用于各个数据文件。1994年2月17－18日，在美国召开了第二次元数据学术讨论会：其目的是解决元数据访问和/或标准化问题，将元数据元素分为三组：（1）主要与信息内容有关的元素；（2）主要与信息的知识产权有关的元素；（3）主要与信息的实例有关的元素。1994年3月2日发表的白皮书将元数据定义为：“关于数据的数据”，或者“应用数据所需要的补充信息”。元数据应用于下列四种不同的方面： (1) 查询、浏览、检索数据；(2) 数据获取、质量保证、再加工；(3) 系统间转换数据；(4) 存储、建立数据档案。1994年5月15－18日在美国华盛顿召开了第三次学术讨论会：会议目的是定义元数据框架 (说明存储数据的数据)。考虑了多种数据类型和格式：图像、音频、录象、表格、栅格、图形、算法和程序、文件等。提高访问数据的速度和应用数据，促进不同学科间的
数据共享。<H4 0cm; TEXT-INDENT: 0cm"><A>2.3.3 美国国家航空和宇宙航行局（NASA</A>）DIF标准</H4>DIF是目录交换格式（Directory Interchange Format）的英文缩写，这是由NASA发布的、主要用于说明遥感数据，特别是卫星遥感数据的一个实际应用的元数据标准。DIF由一系列字段组成，详细说明有关数据的信息。在DIF中，下述六个字段是必需的：登录目录标识、登录目录名称、参数、原始数据中心、数据中心（包括名称、数据集标识、联系人等）及数据概要等（表3）。为使信息更加明晰，并尽可能与FGDC的元数据标准一致，增加了一些字段，如传感器名称、地点、数据分辨率、计划、质量、访问和使用限制、分发、多媒体样本等。新增加的字段有助于用户更好的决定数据集的可用程度。DIF字段中一部分是文本字段，其他字段则使用有效值。表3<TABLE black 0.75pt outset; BORDER-TOP: black 0.75pt outset; BORDER-LEFT: black 0.75pt outset; WIDTH: 450pt; BORDER-BOTTOM: black 0.75pt outset; mso-cellspacing: .7pt" cellSpacing=1 cellPadding=0 width=600 border=1><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>登录目录标识（O）</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>登录目录名称（O）</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>数据集参考资料</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>调查人</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>技术联系</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>学科</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>参数（O）</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>关键字</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>传感器名称</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>资源名称</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>时间跨度</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>数据集进展</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>空间覆盖范围</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>位置</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>时间分辨率</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>计划</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>集成标记</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>质量</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>访问限制</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>使用限制</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>原始数据中心（O）</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>数据中心（名称、数据集标识、联系人）（O）</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>时间分类</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>存贮介质</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>发行信息</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>多媒体样本</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>参考资料</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>数据概要（O）</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>DIF文件作者</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>综合数据网（IDN）结点</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>DIF更新日期</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>下次更新日期</TD></TR><TR><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset" vAlign=top>科学内容更新日期</TD></TR></TABLE>尽管DIF增加了若干字段，以求与FGDC的元数据内容标准一致。但是，它仍然局限于数据字典范畴，重点从数据存储的角度说明数据，缺乏数据分发、数据使用等方面的信息。

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发布于：2004-10-28 15:57

<H5 0cm; TEXT-INDENT: 0cm"><A>一、美国NASA</A>的DIF标准实例</H5>Example of a Skinny DIFEntry_ID: OAR0005Entry_Title: COADS Ship Observations (Monthly Mean)Group: Technical_ContactFirst_Name: DONALDMiddle_Name: R.Last_Name: MOCKEmail: INTERNET > DRM@NOAACRD.COLORADO.EDUPhone: 303-497-6640Group: AddressOAR MASC325 Broadway StreetBoulder, CO 80303-3328USAEnd_GroupEnd_GroupDiscipline: EARTH SCIENCEGroup: ParametersCategory: EARTH SCIENCETopic: ATMOSPHERETerm: CLOUDSEnd_GroupGroup: ParametersCategory: EARTH SCIENCETopic: ATMOSPHERETerm: ATMOSPHERIC WATER VAPORVariable: WATER VAPORDetailed_Variable: Specific HumidityEnd_GroupGroup: Parameters Category: EARTH SCIENCETopic: ATMOSPHERETerm: ATMOSPHERIC TEMPERATUREVariable: AIR TEMPERATUREEnd_GroupGroup: Parameters Category: EARTH SCIENCETopic: ATMOSPHERETerm: ATMOSPHERIC WINDSVariable: WIND STRESSEnd_GroupGroup: Parameters Category: EARTH SCIENCETopic: ATMOSPHERETerm: ATMOSPHERIC WINDSVariable: SURFACE WINDSDetailed_Variable: VECTOR WINDSEnd_GroupGroup: Parameters Category: EARTH SCIENCETopic: OCEANSTerm: OCEAN TEMPERATUREVariable: SEA SURFACE TEMPERATUREEnd_GroupGroup: Parameters Category: EARTH SCIENCETopic: OCEANSTerm: OCEAN WINDSVariable: WIND STRESSEnd_GroupGroup: Parameters Category: EARTH SCIENCETopic: OCEANSTerm: OCEAN WINDSVariable: SURFACE WINDSDetailed_Variable: VECTOR WINDSEnd_Group Keyword: CLOUDINESSKeyword: IDN_NODE GSFC/NOAA/OAR/CMDLKeyword: SEA SURFACE TEMPERATUREKeyword: SSTKeyword: VECTOR WINDSKeyword: WIND STRESSLocation: BOUNDARY LAYERLocation: SEA SURFACEOriginating_Center: NOAA/OAR/CMDLGroup: Data_CenterData_Center_Name: NOAA/OAR/CMDL > Climate Monitoring Diagnostic Laboratory, NOAAGroup: Data_Center_ContactFirst_Name: DONALDMiddle_Name: R.Last_Name: MOCKEmail: INTERNET > DRM@NOAACRD.COLORADO.EDUPhone: 303-497-6640Group: AddressOAR MASC325 Broadway StreetBoulder, CO 80303-3328USAEnd_GroupEnd_GroupEnd_GroupGroup: Summary[A more complete version of this directory entry is in progress. 12/30/93] This directory entry was created from information gathered in a survey conducted as part of NOAA's Data System Modernization program. The following parameters were identified for this data set in thesurvey: Air Temperature,Sea Surface Temperature,Spec. Hum.,Vector Winds,Wind Stress,Cloudiness.End_GroupDIF_Revision_Date: 1994-02-17

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发布于：2004-10-28 15:58

<H4 0cm; TEXT-INDENT: 0cm"><A>2.3.4 美国国际地球科学信息网络中心 (CIESIN) </A>的元数据标准</H4>CIESIN （Center for International Earth Science Information Network）是1989年成立的一个非盈利、非官方组织。其目的是为科学家、决策者和公众提供有关信息，以便更好地认识不断变化的地球。它主要从事全球和地区网络开发、科学数据管理、决策支持、培训、教育和技术咨询服务。它也是世界数据A中心, 存贮大量科学数据。为了对其存储的数据进行有效的管理和便于用户使用，制定了元数据标准，并建立了元数据库，供用户通过网络查询检索。CIESIN的元数据标准内容主要包括：数据库名称、数据库标识、元数据更新日期、调查者、技术联系信息、数据中心、数据采集方法/设备、起始时间、截止时间、时间覆盖范围、数据概要、统计信息、语言、访问/可用性、质量、参数、学科、关键字、参考信息、
科学内容更新日期、下次更新日期等。CIESIN的元数据标准主要是说明科学数据的。已经建立了各个数据库的元数据库，并提供查询工具。用户填写查询界面上的选项，如目录名称、关键字、查询条件、组合关系、查询检索区域范围等，即可获取所需数据的元数据信息。CIESIN的元数据标准与FGDC的CSDGM标准内容上有一定的相似之处，但它主要用来说明关系数据，而后者则主要用来说明地理空间数据。<H4 0cm; TEXT-INDENT: 0cm"><A>2.3.5 澳大利亚、新西兰元数据核心元素标准</A></H4>澳大利亚新西兰土地信息委员会（ANZLIC〕1994－1997年战略计划要求制定和执行澳大利亚新西兰国家土地和地理数据目录系统。1994年，ANZLIC制定了有关元数据的方针，决定在各个管辖区和国家级数据目录系统中，应用最概略的元数据（称之为“元数据核心元素”），而不用详细的全部元数据。该方针包含下列规定： 提出元数据框架方案，确定和定义国家级土地和地理数据目录系统的必须的元数据元素，讨论元数据的建立、维护和目录管理等问题； 各个管辖区向国家级数据目录系统无偿提供各自的元数据核心元素内容； 国家级数据目录系统的元数据核心元素内容应当无偿地提供给各个管辖区； 各个管辖区应当建立机制，以便潜在的用户能自由地、容易地访问元数据。 ANZLIC咨询委员会于1995年4月成立工作组，其任务包括：提出元数据框架方案，确定和定义国家级土地和地理数据目录系统必须的元数据元素，讨论元数据的建立、维护和目录管理等问题； 以元数据框架为基础，建立国家级数据目录系统，决定实施国家级数据目录计划的优先次序及问题； 提出国家级数据目录系统实施计划，包括在各个管辖区及国家级数据目录系统之间转换元数据的方法； 以适合转化为澳大利亚/新西兰国家标准的形式，撰写国家土地和地理数据质量指南的讨论稿，广泛征求意见。 为了鼓励按照ANZLIC建议的结构收集元数据，ANZLIC咨询委员会还要求工作组就开发基于PC机的、公共的元数据输入软件产品的可行性、费用及效益，提出报告。1995年7月ANZLIC 元数据标准工作组完成“澳大利亚和新西兰土地及地理数据目录元数据框架”讨论稿，提交所有管辖区土地信息协调机构和有关部门征求意见。该讨论稿确定了最少量的元数据核心元素，用于澳大利亚和新西兰所有高等级数据目录，作为国家统一的数据目录系统的基础。这样做的主要理由是： 在需要的主题方面是否有现成的数据； 数据集覆盖什么范围； 提供数据集内容和质量的概要信息，以便用户决定是否进一步查询数据集； 提供进一步的联系信息。 通过讨论认为制定元数据标准和建立国家土地信息的元数据目录系统，是使用户更加容易获得地理数据的重要步骤。1995年12月提出了第二个草案：土地和地理数据目录元数据核心元素标准建议。许多领域要求土地和地理信息的元数据的内容包括： 有关数据采集方法、集成和分析技术的详细信息； 有关原始数据集的精度、处理过程、管理单位数据的归档手续信息； 有关投影、比例尺信息和数据字典，以帮助将数据转换到其他单位； 数据集内容、质量和地理覆盖范围的适当说明，以便潜在用户能够评价对其应用的适宜性； 联系信息等。 元数据核心元素是所有类型数据所共同的，说明现有什么数据、数据内容、地理覆盖范围、对于其他应用可能有什么作用，以及何处可以获得有关数据的更多信息等。

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发布于：2004-10-28 16:18

<H4 0cm 0cm 7.8pt; TEXT-INDENT: 0cm"><A>2.3.7 ISO/TC211 </A>元数据体系</H4>ISO/TC 211成立于1994年，它是在全球信息化浪潮的冲击下发展起来的一个关于地理信息/地球信息业的标准化技术委员会。它的目的是建立一个处理与地球位置有直接或间接关系的地理对象或现象的标准体系，包括数字地理信息的获取、处理、分析、访问、表示以及转换的方法、工具和服务体系。该委员会由框架和参考模型（WG 1）、地理空间数据模型和算法（WG 2）、地理空间数据管理（WG 3）、地理空间服务（WG 4）、以及专用（Profile）标准（WG 5）五个工作组组成。每个工作组又由一定数量的工作小组组成，共有二十个工作小组（另外，影像与格网数据、实用标准两个工作小组正在建立之中），标准的制定工作便由工作小组来完成。元数据属于第三工作组总第15工作小组，即15046-15，它以地理信息的实时性、精度、数据内容和属性、数据来源、价格、图层、以及适用性等为考虑对象。表3.3 ISO/TC 211标准技术委员会<DIV align=center><TABLE 461.25pt; mso-cellspacing: .7pt; mso-padding-alt: 6.75pt 6.75pt 6.75pt 6.75pt" cellSpacing=1 cellPadding=0 width=615 border=1><TR 8.25pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 49%; PADDING-TOP: 6.75pt; HEIGHT: 8.25pt" vAlign=top width="49%">　WG 1：框架和参考模型</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 51%; PADDING-TOP: 6.75pt; HEIGHT: 8.25pt" vAlign=top width="51%">15046-1 参考模型15046-2 综述15046-3 概念模式语言15046-4 术语15046-5 一致性与测试16569 影像与格网数据</TD></TR><TR 6pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 49%; PADDING-TOP: 6.75pt; HEIGHT: 6pt" vAlign=top width="49%">　WG 2：地理空间数据模型和算法</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 51%; PADDING-TOP: 6.75pt; HEIGHT: 6pt" vAlign=top width="51%">15046-7 空间子模式15046-8 时间子模式15046-9 应用模式规则15046-20 空间算法</TD></TR><TR 17.25pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 49%; PADDING-TOP: 6.75pt; HEIGHT: 17.25pt" vAlign=top width="49%">　WG 3：地理空间数据管理</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 51%; PADDING-TOP: 6.75pt; HEIGHT: 17.25pt" vAlign=top width="51%">15046-10 分类15046-11 大地参照系15046-12 间接参照系15046-13 质量15046-14 质量评价过程15046-15 元数据</TD></TR><TR 17.25pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 49%; PADDING-TOP: 6.75pt; HEIGHT: 17.25pt" vAlign=top width="49%">WG 4：地理空间服务</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 51%; PADDING-TOP: 6.75pt; HEIGHT: 17.25pt" vAlign=top width="51%">15046-16 定位服务15046-17 描绘15046-18 编码15046-19 服务</TD></TR><TR 17.25pt"><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 49%; PADDING-TOP: 6.75pt; HEIGHT: 17.25pt" vAlign=top width="49%">WG 5：专用标准</TD><TD 6.75pt; PADDING-LEFT: 6.75pt; PADDING-BOTTOM: 6.75pt; WIDTH: 51%; PADDING-TOP: 6.75pt; HEIGHT: 17.25pt" vAlign=top width="51%">15046-6 专用标准15854 实用标准</TD></TR></TABLE></DIV> ISO/TC 211自1994年成立以来，就将“地理信息－元数据”作为其首批研制的20个国际标准之一，编号为ISO15046－15。由美国NIMA的David Danko先生担任项目负责人。几年来，参加该项标准研制的第三工作组专家，经过艰苦的努力，于1996年3月完成第一版工作草案 (WD v.1.0)。迄今经过多次修改，先后完成近10个更新版本，今年5月完成最后一版工作草案 (WD v.4.4)，已作为委员会草案 (CD)提交给ISO/TC 211各成员团体征求意见。该标准以FGDC等现有标准为基础，按照国际标准化组织制定的标准导则要求制定。其工作范围是：定义说明地理信息和服务所需要的信息。它提供有关数字地理数据标识、覆盖范围、质量、空间和时间模式、空间参照系统和发行等信息。该标准适用于数据集编目、数据交换网络，以及数据集的详尽说明。适用于地理数据集、数据集系列、地理要素和属性。它定义： 必选和一定条件下必选的元数据实体和元素──提供元数据应用、数据发现、决定数据对于应用的适合程度、数据访问、数据转换和数据应用所需要的最少的核心内容； 可选的元数据元素──如果需要，对地理数据的更加详细的标准说明； 为适应特殊需要对元数据进行扩展的方法。 尽管该标准是用于数字数据的，它的原则也能扩展用于许多其他形式的地理资料，如地图、图表、文本文件等。该标准的正文内容包括：工作范围、一致性、引用标准、术语和定义、符号 (和缩写词)、元数据要求等。附录包括：A. 元数据特征、B. 元数据模型、C. 元数据扩展和专用标准 (Profile)、D. 元数据的ISO标准相互参照、E. 元数据扩展方法、F. 元数据实施、G. 元数
据的等级、H. 实施示例、J. 参考文献。 标准确定了两级元数据，即： 标准中定义了两级元数据：l 一级元数据：主要用于支持数据编目和空间信息交换中心的数据发现服务，包含了53个元数据元素。l 二级元数据：提供了更完全的数据集描述，包含了13种类型的元数据[7]：1. 标识信息(Identification information )2. 数据质量信息（Data Quality information）3. 谱系信息(Lineage information)4. 空间数据表示(Spatial data representation )5. 参考系统信息（Reference system information）6. 特征目录信息（Feature catalogue information）7. 发布信息(Distribution information )8. 元数据参考信息(Meta data reference information )9. 引用信息（Citation information ）10. 数据负责者信息（Responsible party information ）11. 地址信息（Address information ）12. 范围信息( Extent information )13. 在线资源信息（ On-line resource information ）其中前8个是元数据的子集而后5个是可重复的实体，它们不能单独使用，总是作为一个单元出现在8个子集中。更详细的内容如下：一级元数据－—编目信息包含数据集编目所需的最少的元数据内容。 二级元数据，它包含八个子集和三个可重复的实体。八个子集是： 标识信息。包含唯一标识一个数据集、说明其空间和时间范围、
状况、法律限制和保密限定所需的信息； 时间质量信息。包含数据集质量的一般评价； 数据志信息。包含有关数据集应用、数据源，以及生产数据集时所用的工艺方法； 空间数据表示信息。包含与数据集中表示空间信息所用方法有关的信息； 参照系统信息。包含数据集中应用的空间和时间参照系统说明； 要素分类信息。包含数据集中具有的要素类型、要素功能、要素属性和要素关系的定义和说明； 发行信息。包含有关获取信息所需的数据发行者及买卖权限的信息； 元数据参考信息。包含元数据现势性及其负责单位信息。 三个可重复的实体不是独立的元数据子集，它们不单独使用，而总是作为一个单元插在前述某一个子集中，且仅作为该子集的实体和元素。这三个可重复的实体是： 引用文献信息实体。提供引用文献的标准格式； 负责单位信息实体。包含与数据集有关的单位和/或个人的标识； 地址信息实体。提供与数据集有关的单位和/或个人的地址及其
他通信办法。 标准定义了每个元数据子集、实体和元素的八个特征，即名称、标识码、定义、性质、条件、最大出现次数、数据类型和值域。下表 (表5) 是一级元数据－—编目信息的几个元素的特征表实例。

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16楼^#

发布于：2004-10-28 16:18

表5<TABLE black 0.75pt outset; BORDER-TOP: black 0.75pt outset; BORDER-LEFT: black 0.75pt outset; WIDTH: 450pt; BORDER-BOTTOM: black 0.75pt outset; mso-cellspacing: .7pt" cellSpacing=1 cellPadding=0 width=600 border=1><TR 13.5pt"><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 6%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 13.5pt" vAlign=top width="6%">序号</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 13%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 13.5pt" vAlign=top width="13%">名称</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 11%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 13.5pt" vAlign=top width="11%">标识符</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 21%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 13.5pt" vAlign=top width="21%">定义</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 6%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 13.5pt" vAlign=top width="6%">性质</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 11%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 13.5pt" vAlign=top width="11%">最大出现次数</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 17%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 13.5pt" vAlign=top width="17%">数据类型</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 15%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 13.5pt" vAlign=top width="15%">值域</TD></TR><TR 51.75pt"><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; BACKGROUND: silver; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 6%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 51.75pt" vAlign=top width="6%">1</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; BACKGROUND: silver; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 13%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 51.75pt" vAlign=top width="13%">编目信息</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; BACKGROUND: silver; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 11%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 51.75pt" vAlign=top width="11%"> </TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; BACKGROUND: silver; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 21%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 51.75pt" vAlign=top width="21%">唯一标识完整数据集和/或数据集系列的信息</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; BACKGROUND: silver; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 6%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 51.75pt" vAlign=top width="6%">M</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; BACKGROUND: silver; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 11%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 51.75pt" vAlign=top width="11%">1</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; BACKGROUND: silver; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 17%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 51.75pt" vAlign=top width="17%">元数据子集</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; BACKGROUND: silver; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 15%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 51.75pt" vAlign=top width="15%">序号2－55</TD></TR><TR 12.75pt"><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 6%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="6%">2</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 13%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="13%">名称</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 11%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="11%"> </TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 21%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="21%">数据集名称</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 6%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="6%">M</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 11%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="11%">1</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 17%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="17%">文本</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 15%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="15%">任意长文字</TD></TR><TR 12.75pt"><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 6%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="6%">3</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 13%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="13%">版本</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 11%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="11%"> </TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 21%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="21%">数据集版本</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 6%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="6%">O</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 11%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="11%">1</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 17%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="17%">文本</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 15%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 12.75pt" vAlign=top width="15%">任意长文字</TD></TR><TR 25.5pt"><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 6%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 25.5pt" vAlign=top width="6%">4</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 13%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 25.5pt" vAlign=top width="13%">系列名</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 11%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 25.5pt" vAlign=top width="11%"> </TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 21%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 25.5pt" vAlign=top width="21%">数据集所属的系列产品总称</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 6%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 25.5pt" vAlign=top width="6%">O</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 11%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 25.5pt" vAlign=top width="11%">1</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 17%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 25.5pt" vAlign=top width="17%">文本</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 15%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 25.5pt" vAlign=top width="15%">任意长文字</TD></TR><TR 46.5pt"><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 6%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 46.5pt" vAlign=top width="6%">5</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 13%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 46.5pt" vAlign=top width="13%">出版标识</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 11%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 46.5pt" vAlign=top width="11%"> </TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 21%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 46.5pt" vAlign=top width="21%">数据集所属的系列产品出版标识信息</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 6%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 46.5pt" vAlign=top width="6%">O</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 11%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 46.5pt" vAlign=top width="11%">1</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 17%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 46.5pt" vAlign=top width="17%">文本</TD><TD black 0.75pt inset; PADDING-RIGHT: 0.75pt; BORDER-TOP: black 0.75pt inset; PADDING-LEFT: 0.75pt; PADDING-BOTTOM: 0.75pt; BORDER-LEFT: black 0.75pt inset; WIDTH: 15%; PADDING-TOP: 0.75pt; BORDER-BOTTOM: black 0.75pt inset; HEIGHT: 46.5pt" vAlign=top width="15%">任意长文字</TD></TR></TABLE>目前，该标准工作草案一级元数据包含55个元数据实体和元素,二级元数据的8个子集和3个可重复使用的实体共包括452个实体和元素。考虑到不同数据集、数据集系列、要素和属性的不同特点，工作草案不但定义了子集、实体和元素的3种性质，即必选、在一定条件下必选和可选，而且提供了扩展的方法和摘录其部分内容的原则与方法。该标准是迄今最为完整，也最为复杂的标准方案。它的制定，必将影响许多国家的地理信息元数据标准的制定和实施，并进而对全球数据管理与服务产生很大影响。国际标准化组织ISO作为全球标准的权威机构，对地理数据标准化问题一直比较重视。1994年后期，国际标准化组织面对地理信息数据标准化的趋势，成立了地理信息/地球信息业技术委员会，即ISO/TC 211编号为 15046，用于专门研究和建立一个处理与地球位置有直接或间接关系的地理对象或现象的标准体系，包括数字地球信息的获取、处理、分析、访问表示以及转换的方法、工具和服务体系等内容。该委员会由框架和参考模型（WG 1）、地理空间数据模型和算法(WG 2) 、地理空间数据管理（WG 3）、地理空间服务（WG 4）、以及行业及功能标准（WG 5）5 个工作组组成[5]。该标准是至今最完整、也是最为复杂的元数据标准方案。它的制定，必将影响许多国家的地理信息元数据标准的制定和实施，并进而对全球数据管理与服务产生很大的影响[6]。 <H5 0cm; TEXT-INDENT: 0cm"><A>一、ISO</A>地理信息元数据标准实例</H5>Example 1- etadata for a vector dataset provided at conformance level 1Title>Digital Chart of the WorldReference date>199208Responsible party information:Responsible party organisation name>Defense Mapping AgencyResponsible party role code>1Postal address>8613 Lee HighwayCity>FairfaxAdministrative Area>VirginiaPostal Code>22031Country>USResponsible party information:Responsible party organisation name>National Imagery and Mapping AgencyResponsible party role code>3 Postal address>4600 Sangamore Rd.City>BethesdaAdministrative Area>MarylandPostal Code>20816-5003Country>USOn-line resource linkage >http://www.nima.milDataset extent:Geographic extent coordinates:West bounding coordinate> -180.0East bounding coordinate> 180.0North bounding coordinate> 90.0South bounding coordinate> -90.0Temporal extent date/time>199208Language of dataset code>enAbstract>The Digital Chart of the World is a comprehensive 1:1,000,000 scale vector basemap of the world. Itconsists of cartographic, attribute, and textual data stored on compact disc read only memory (CD-ROM). The database contains more than 1,500 megabytes of vector data and is organized into 17 thematic layers. The data includes major road and rail networks, major hydrologic drainage systems, major utility networks (cross-country pipelines and communication lines), all major airports, elevation contours (1000 foot(ft), with 500ft and 250ft supplemental contours), coastlines, international boundaries and populated places. The DCW also has an index
of geographic names to aid in locating areas of interest. The database can be accessed directly from the four optical CD-ROMs that store the database or can be transported.Purpose>The Digital Chart of the World is a general purpose global database designed to support Geographic Information Systems applications.Progress code>1Resolution level code>0Category:Theme code>1Theme code>2Theme code>3Theme code>5Theme code>8Theme code>10Theme code>18

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发布于：2004-10-28 16:18

Keyword information:Keyword(s)> roads, railroads, rivers, lakes, streams, utility networks, airports, elevation contours, coastlines, international boundaries, populated places, geographic namesKeyword type code>2Access constraints>noneUse constraints>Cite Defense Mapping AgencyLineage statement> The primary source for the database is the Defense Mapping Agency's (DMA) Operational Navigation Chart (ONC) series.Qualitative narrative report>100% of attribute codes were reviewed against the source manuscriptsSpatial representation type code>2Spatial reference system type code>2Distribution identifier>DCWXXXPACKDistribution format name>Vector Product FormatDistribution media>CD-ROMLevel of conformance code>1Language of metadata code>enMetadata date>19971130Example 2 -- Metadata for a vector dataset provided at conformance level 2Language of dataset code>enAbstract> The Digital Chart of the World is a comprehensive 1:1,000,000 scale vector basemap of the world. It consists of cartographic, attribute, and textual data stored on compact disc read only memory (CD-ROM). The primary source for the database is the Defense Mapping Agency's (DMA) Operational Navigation Chart (ONC) series. This is the largest scale unclassified map series in existence that provides consistent, continuous global coverage of essential basemap features. The database contains more than 1,500 megabytes of vector data and is organized into 17 thematic layers. The data includes major road and rail networks, major hydrologic drainage systems, major utility networks (cross-country pipelines and communication lines), all major airports, elevation contours (1000 foot(ft), with 500ft and 250ft supplemental contours), oastlines, international boundaries and populated places. The DCW also has an index of geographic names to aid in locating areas of interest. The database can be accessed directly from the four optical CD-ROMs that store the database or can be transferred to a magnetic media.Purpose> The Digital Chart of the World is a general purpose global database designed to support Geographic Information Systems applications.Identification citation:Title>Digital Chart of the WorldAlternate title>DCWCitation responsible party information:Responsible party organisation name>Defense Mapping AgencyResponsible party role code>1Responsible party address:Postal address>8613 Lee HighwayCity>FairfaxAdministrative area>VirginiaPostal code>22031Country>USResponsible party organisation name>National Imagery and
Mapping AgencyResponsible party role code>3Responsible party address:Postal address>4600 Sangamore Rd.City>BethesdaAdministrative Area>MarylandPostal Code>20816-5003Country>USOn-line resource linkage >http://www.nima.milReference date>199208Reference date type>publication datePresentation form code>6Status:Progress code>1Maintenance information:Maintenance ; update frequency code>6Dataset extent:Geographic extent coordinates:West bounding coordinate>-180.0East bounding coordinate>180.0North bounding coordinate>90.0South bounding coordinate>-90.0Identification extent information:Temporal extent:Temporal extent date/time>199208Temporal extent date/time description>2Resolution level code>0Category:Theme code>1Theme code>2Theme code>3Theme code>5Theme code>8Theme code>10Theme code>18Keyword information:Keyword(s)> roads, railroads, rivers, lakes, streams, utility networks, airports, elevation contours, coastlines, international boundaries, populated places, geographic namesKeyword type code>2Keyword information:Keyword(s)>DCW, Global digital database, global coverage, world coverageKeyword type code>3Primary point of contact>Responsible party organisation name>National Imagery and Mapping AgencyResponsible party address:Postal address>4600 Sangamore Rd.City>BethesdaAdministrative Area>MarylandPostal Code>20816-5003Country> USOn-line resource linkage >http://www.nima.milDataset constraints:Legal constraints:Access constraints>NoneUse constraints>Cite Defense Mapping AgencySecurity information:Security classification system>United States Department of DefenseSecurity classification>UnclassifiedData quality:Data quality assessment:Data quality report type code>22Qualitative assessment:Qualitative narrative report>100 percent of attribute codes were
reviewed against the source manuscriptsData quality assessment:Data quality report type code>8Quantitative assessment:Quantitative report:Quantitative conformance measure:Conformance specification>MIL-D-89009Conformance explanation> The horizontal positional accuracy value represents overall accuracy. Source chart-specific accuracy's are available as area feature attributes in the DCW data quality coverage. The primary accuracy analysis was performed on one chart only in the prototyping phase of the project. Detailed horizontal accuracy figures were developed by comparing the positions of well-defined points in the roads, railroads, utility lines, and drainage coverage's against sources of higher accuracy, measuring the offsets, and expressing differences as a Circular Map Accuracy figure at a 90% confidence interval. This figure was independently verified by adding known production errors to source chart accuracy's in a root sum square
calculation.Conformance code>2Quantitative results:Data quality value domain>-2040Data quality result>metersData quality error statistic term>90% circular errorData quality assessment:Data quality report type>8Quantitative assessment:Quantitative report:Quantitative conformance measure:Conformance specification> MIL-D-89009Conformance explanation> Vertical accuracy figures were developed by comparing elevation contour locations on 1:24,000 scale maps to elevation values at the same location within the digital database. Some manual interpolation was necessary to complete this test. The analysis results are expressed as linear error at a 90% confidence interval..Conformance code>2Quantitative results:Data quality value domain>610Data quality result>metersData quality error statistic term>90% linear errorLineage:Lineage report:Source information:Source description>stable-base materialSource date/time>1974Source date/time>1991Source scale denominator>1000000Source datum>European 1950Source citation:Title>Operational Navigational ChartAlternate title>ONCCitation responsible party:Responsible party organisation name>Defense Mapping AgencyResponsible party role code>1Responsible party address:City>St. LouisAdministrative area>MOCountry> USReference date>1991112Reference date type>publication datePresentation form code>1Process step:

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发布于：2004-10-28 16:18

Process description>Stable-based positives were produced from the original reproduction negatives (up to 35 per ONC sheet) these were digitized either through a scanning-raster to vector conversion or hand digitised into vector form. The vector data was then tagged with attribute information using ARC-INFO software. Transformation to geographic coordinates was performed using the projection graticules for each sheet. Digital information was edge matched between sheets to create large regional datasets. These were then subdivided into 5 x 5 tiles and converted from ARC/INFO to VPF. The data was then pre-mastered for CD-ROM. QC was performed by a separate group for each step in the production process.Process date/time>199112Process contact:Responsible party organisation name>Environmental Systems Research Institute, Applications DivisionResponsible party address:Postal address>380 New York St.City>RedlandsAdministrative area>CaliforniaPostal code>92373Country> USVoice telephone>(909) 793-2853Facsimile telephone>(909) 793-5953Source information:Source description>magnetic, Airport records (name, ICAO, position,
elevation, and type)Source date/time>1991Source citation:Title>Digital Aeronautical Flight Information FileAlternate title>DAFIFCitation responsible party:Responsible party organisation name>Defense Mapping AgencyResponsible party role code>1Responsible party address:City>St. LouisAdministrative area>MOCountry> USReference date>199111Reference date type>publication datePresentation form code>8Process step:Process description>Transferred digitally directly into the VPF files.Process date/time>199111Process contact:Responsible party organisation name>Environmental Systems
Research Institute, Applications DivisionResponsible party address:Postal address>380 New York St.City>RedlandsAdministrative area>CaliforniaPostal code>92373Country> USVoice telephone>(909) 793-2853Facsimile telephone>(909) 793-5953Source information:Source description>stable-base material, All information found on the source with the exception of aeronautical data. JNCs were used as source for the Antarctica region only.Source date/time>1974Source date/time>1991Source scale denominator>2000000Source datum>unknownSource citation:Title>Jet Navigation ChartAlternate title>JNCCitation responsible party:Responsible party organisation name>Defense Mapping AgencyResponsible party role code>1Responsible party address:City>St. LouisAdministrative area>MOCountry> USReference date>199111Reference date type>publication datePresentation form code>1Process step:Process description>Stable-based positives were produced from the original reproduction negatives (up to 35 per JNC sheet) these were digitized either through a scanning-raster to vector conversion or hand digitized into vector form. The vector data was then tagged with attribute information using ARC-INFO software. Transformation to geographic coordinates was performed using the projection graticules for each sheet. Digital information was edge matched between sheets to create large regional datasets. These were then subdivided into 5 x 5 tiles and converted
from ARC/INFO to VPF. The data was then pre-mastered for CD-ROM. QC was performed by a separate group for each step in the production process.Process date/time>199112Process contact:Responsible party organisation name>Environmental Systems Research Institute, Applications DivisionResponsible party address:Postal address>380 New York St.City>RedlandsAdministrative area>CaliforniaPostal code>92373Country> USVoice telephone>(909) 793-2853Facsimile telephone>(909) 793-5953Source information:Source description>Six vegetation types covering the continental
United StatesSource date/time>199003Source date/time>199011Source scale denominator>1000000Source datum>WGS 84Source citation:Title>Advanced Very High Resolution RadiometerAlternate title>AVHRRCitation responsible party:Responsible party organisation name>USGS EROS Data CentreResponsible party role code>1Responsible party address:City>Sioux FallsAdministrative area>SDCountry> USReference date>1991Reference date type>publication datePresentation form code>4Process step:Process description>Daily AVHRR images were averaged for two week time periods over the entire US growing season. These averaged images, their rates of change, elevation information, and other data were used to produce a single land classification image of the continental US.Process date/time>199108Process contact:Responsible party organisation name>USGS EROS Data CentreResponsible party address:City>Sioux FallsAdministrative area>SDPostal code>12345Country> USProcess step:Process description> The Eros data (raster files) were converted to vector polygon, splined (remove stairstepping), thinned (all polygons under 2km 2 were deleted), and tied to existing DCW polygons (water bodies, built-up areas). The resulting file was tiled and converted to a
VPF Vegetation coverage for use in the DCW. All processing was performed using ARC-INFO software.Process date/time>199110Process contact:Responsible party organisation name> Environmental Systems
Research Institute, Applications DivisionResponsible party address:Postal address>380 New York St.City>RedlandsAdministrative area>CAPostal code>92373Country> USVoice telephone>(909) 793-2853Facsimile telephone>(909) 793-5953Spatial representation type code>2Vector spatial representation information:Point and vector object type code>1Level of topology code>3Vector spatial representation information:Point and vector object type code>2 Level of topology code>3Vector spatial representation information:Point and vector object type code>3Level of topology code>3Spatial reference information:Spatial reference system type code>2Spatial reference by coordinates:Compound coordinate reference system:Compound coordinate reference system (CRS) identifier>
unknownCRS 1 identifier>WGS 84CRS 2 identifier>unknownCoordinate reference system:CRS identifier>WGS 84CRS citation:Title>NATO STANAG 2211Citation responsible party:Responsible party organisation name>NATOResponsible party address:Country> USReference date>1998Coordinate reference system:CRS identifier>unknownCRS datum identifier>unknownCRS coordinate system identifier>unknownDatum:Datum identifier>unknownDatum type code>2External feature catalogue:Feature catalogue citation:Title>Military Specification-Digital Chart of the WorldAlternate title>MIL-D-89009Citation responsible party:Responsible party organisation name>US Department of Defense,
Defense Printing Service Detachment OfficeResponsible party role code>2Responsible party address:City>PhiladelphiaCountry> USReference date>1992Feature catalogue compliance code>1Distributor information:Distributor:Responsible party organisation name> Defense Mapping AgencyResponsible party role code>7Responsible party address: 8613 Lee HighwayCity> FairfaxAdministrative area> VirginiaPostal code>22031Country> USStandard order process:Fees>$200Ordering instructions> Payment (check, money order, purchase order, or Government account) must accompany order. Make all drafts payable to Dept. of the Interior - US Geological Survey.Distribution format information:Distribution format name>Vector Product FormatDistribution format version date>19920413Distribution format specification>MIL-D-89009Digital transfer options:Distribution media>CD-ROMNumber of volumes>4Recording capacity:Recording format>ISO 9660Distributor information:Distributor: Responsible party organisation name>USGS Open File SectionResponsible party role code>7Responsible party address:City>DenverAdministrative area>ColoradoCountry> USStandard order process:Ordering instructions> DoD customers onlyDistribution format information:Distribution format name>Vector Product FormatDistribution format version date>19920413Distribution format specification>MIL-D-89009Digital transfer options:Distribution media>CD-ROMNumber of volumes>4Recording capacity:Recording format>ISO 9660Metadata file identifier>15046-15-Case2Metadata date information:Metadata date>19940720Metadata contact:Responsible party organisation name>National Imagery and
Mapping AgencyResponsible party address:Postal address>4600 Sangamore Rd.

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发布于：2004-10-28 16:19

City>BethesdaAdministrative area>MarylandPostal code>20816-5003Country> USOn-line resource linkage >http://www.nima.milMetadata standard information:Metadata standard name>ISO 15046-15 Metadata standard version>3.1Level of conformance code>2<H3 0cm; TEXT-INDENT: 0cm"><A>2.4 中国标准</A></H3><H4 0cm; TEXT-INDENT: 0cm"><A>2.4.1 基于我国NSII</A>关键技术研究的元数据标准内容体系</H4>(选自赵永平、承继成、李琦、陈爱军、李浩川的同名文章)<H5 0cm; TEXT-INDENT: 0cm"><A>一、概述</A></H5>本文基于我国国家空间信息基础设施（NSII）关键技术研究中的元数据标准研究，提出了一套适合地理空间信息网络化发展的元数据标准草案。该标准草案由两个层次组成，适合在Internet等技术支持下利用分布式环境共享地理空间信息，对地学数据资源的共享具有重要意义。随着信息高速公路以及全球空间数据基础设施的提出，地理界正面临着比计量革命更加深远的信息革命的浪潮。这一趋势伴随“3S”（即GIS、RS、GPS）一体化、网络通讯、计算机技术、Web GIS、以及VRGIS等技术的日益成熟，正在Teledisk、Internet 2的冲击下，向数字地球时代迈进。然而，在通向全球信息化的光明大道上，地理学这门作为“科学之母”的古老学科，却遇到了前所未有的“拦路虎”----地理信息数据共享的难题。目前国际社会已开始着手地理信息标准化的研究工作，以寻求这一问题的解决方案。美国联邦地理数据委员会（FGDC）、开放GIS协会（OGC）、欧洲地理信息标准化技术委员会（CEN/TC 287）、以及国际标准化组织地理信息/地球信息业技术委员会（ISO/TC 211）等组织已成立了各自的工作组，并从影响地理数据发展的不同方面，开始讨论地理信息共享标准的制定工作，元数据标准则作为他们主要的攻关课题，成为各个组织首要研究的内容，以至美国副总统戈尔在最近的“数字地球”项目中也把元数据列为其首要发展的六大技术之一。[Al Gore,1998]1. 元数据的形成当提及“元数据”时，许多人会认为它是一个复杂的体系，仅适用于信息技术和计算机科学。事实上，元数据在地理界已用了几个世纪了，比如早期地图和海图中的图例等，只是当我们把计算机引入该学科后，元数据标准的重要性才被人们逐渐认识到[David Danko,1997]。当利用计算机来表示地理现实时，为了使用户能够理解地理信息，在不同计算机上交换数据，人们希望用一种统一的格式来表示地理信息，这时古老的元数据方法便被正式引入地理界，被赋予了新的含义，出现了“元数据”这一时髦的概念。而随着目前全球信息化和建立空间数据基础设施的发展，即将迈入空间数据基础设施时代的地理界对元数据的需求变得更加紧迫。2. 元数据的理解对地理界之外的元数据，大家极容易理解。如每天在图书馆中使用的卡片分类、CD唱片目录、用户手册以及各种说明书等。而在地理界，最典型的元数据便是各种地图中的图例内容，如图名、数据源、比例尺、精度、生产者、各种符号、航海注意事项以及其它所有可以在地图上找到的描述信息均为元数据。通过元数据，人们拿起一张地图便可以理解和使用它。事实上，元数据是“关于数据的数据”或“关于信息的信息”，它在地理信息中用于描述地理数据集的内容、质量、表示方式、空间参照系、管理方式以及数据集的其它特征，它是实现地理空间数据集共享的核心内容之一。它具有下列几个特点：是用于描述信息资源的高度结构化数据；可以管理和组织信息；可以挖掘信息资源；也可以帮助人们准确地查询所需要的信息，并在从不同的资料或组织获取数据时，可以通过对相同的元数据元素进行比较和对比，获取自己所需要的信息内容。它是打开对多源数据资料进行获取、智能分析以及运算大门的钥匙。<H5 0cm; TEXT-INDENT: 0cm"><A>二、元数据研究现状</A></H5>见国际标准部分。 <H5 0cm; TEXT-INDENT: 0cm"><A>三、元数据标准草案建议</A></H5>通过对CEN/TC 287、FGDC以及ISO/TC 211等元数据标准体系的分析，以及对整个数字地理信息标准化理论前提的认真研究，我们提出了一套基于国家空间信息基础设施关键技术研究的元数据标准体系。该体系共由12个部分组成，其中标准化内容包括标识信息、数据质量信息、数据集继承信息、空间数据表示信息、空间参照系信息、实体和属性信息、发行信息、以及元数据参考信息等8个方面的内容，另外还有4个部分是标准化部分中必须引用的信息，它们为引用信息、时间范围信息、联系信息及地址信息。1. 组织原则该元数据标准由两层组成，其中第一层是目录层，它所提供的元数据复合元素和数据元素是国家空间数据交换中心上查询地理数据的目录信息，它相对概括了第二层中的一些必选项信息，是元数据体系内容中的比较宏观的信息；第二层是元数据标准的主体，它由8个标准部分和4个引用部分组成，包括了全面描述地理空间信息的必选项、条件必选项、以及可选项的内容。

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