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DCW Data Quality Polygons
- Identification Information
- Data Quality Information
- Spatial Data Organization Information
- Spatial Reference Information
- Entity and Attribute Information
- Distribution Information
- Metadata Reference Information
- Identification Information
- Citation
- Originator
- National Imagery and Mapping Agency (now National Geospatial-Intelligence Agency)
- Publication Date
- 19920701
- Title
- DCW Data Quality Polygons
- Edition
- First
- Geospatial Data Presentation Form
- vector digital data
- Publication Information
- Publication Place
- Fairfax, VA
- Publisher
- National Imagery and Mapping Agency
- Online Linkage
- https://hgl.harvard.edu/catalog/harvard-dcw-dq-poly
- Abstract
- This datalayer is a polygon coverage representing data quality features throughout DCW (Digital Chart of the World) geographic coverage as of 1992. The Data Quality Polygon Related Attribute Table contains text describing specific conditions occurring within the database. Typically, this refers to edge-match problems observed between the ONC source maps and steps taken to alleviate those problems. A unique line identification number and the data layer to which the description refers are also present in the file. The key (relate) item for accessing the DQAREA.RAT file from the data quality coverage (DQNET) is ONC sheet name (DQPYSID). This layer was derived from the VMAP0 series produced by the National Geospatial-Intelligence Agency (NGA), formerly known as NIMA (National Imagery and Mapping Agency), an agency of the United States government. VMAP data set products use the "vector product format" (vpf). The term "VMap" is derived from "Vector Smart Map." 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. The primary source for the database is the National Imagery and Mapping Agency's (NIMA) 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 coverage is is organized into 10 thematic layers which feature a vast number of files organized into libraries. These libraries, or coverages, are geographicially bounded areas, rather than feature-linked coverages. DCW Layers in the Harvard Geospatial Library are feature-based as we have processed the multiple tiles from the VMAP0 libraries into a series of seamless coverages (e.g. aeronautical features appear in a single layer, "Aeronautical Facilities, Points") which depict a particular feature as it occurs throughout the available geographic coverage areas. Since different geographic areas were mapped by NIMA at different times using various types of feature capture and scanning and digitizing methods and software, multiple map sources of varying dates and multiple processing approaches are represented in each of these HGL layers. We have necessarily generalized the discussion of data source material and process steps in the Data Quality section of this metadata document.
- Purpose
- The Digital Chart of the World is a general purpose global database designed to support Geographic Information Systems applications. This layer is intended for researchers, students, and policy makers for reference and mapping purposes, and may be used for basic applications such as viewing, querying, and map output production. This layer will provide a basemap for layers related to socio-economic and political anaylsis, statistical enumeration and analysis, or to support graphical overlays and analysis with other spatial data. More advanced user applications may focus on demographics, urban and rural land use planning and related areas including defining boundaries, managing assets and facilities, integrating attribute databases with geographic features, spatial analysis, and presentation output.
- Supplemental Information
- Entities (features) and Attributes for DCW are fully described in: Department of Defense, 1992, Military Specification Digital Chart of the World (MIL-D-89009): Philadelphia, Department of Defense, Defense Printing Service Detachment Office. The DCW used a product-specific attribute coding system that is composed of TYPE and STATUS designators for area, line, and point features; and LEVEL and SYMBOL designators for text features. The TYPE attribute specifies what the feature is, while the STATUS attribute specifies the current condition of the feature. Some features require both a TYPE and STATUS code to uniquely identify their characteristics. In order to uniquely identify each geographic attribute in the DCW, the TYPE and STATUS attribute code names are preceded by the two letter coverage abbreviation and a two letter abbreviation for the type of graphic primitive present. The DCW Type/Status codes were mapped into the Feature Attribute Coding Catalogue (FACC) coding scheme. A full description of FACC may be found in The DIgital Geographic Information Exchange STandard (DIGEST) Edition 1.2, January 1994. Please consult the DIGEST FACC website for complete coding data. (http://www.digest.org/html/DIGEST_2-1_Part4_AnnexB.pdf)
- Temporal Extent
- Currentness Reference
- publication date
- Time Instant
- 19920701
- Bounding Box
- West
- -180.000000
- East
- 180.000000
- North
- 90.000000
- South
- -90.000000
- ISO Topic Category
- boundaries
- location
- Theme Keyword
- Boundaries
- Quality control
- Theme Keyword Thesaurus
- LCSH
- Theme Keyword
- Data Quality
- Theme Keyword Thesaurus
- DIGEST FACC
- Place Keyword
- Northern Hemisphere
- Southern Hemisphere
- Eastern Hemisphere
- Western Hemisphere
- Africa
- Asia
- Australia
- Europe
- North America
- South America
- Polar regions
- Place Keyword Thesaurus
- LCSH
- Temporal Keyword
- Access Restrictions
- None
- Use Restrictions
- For educational, non-commercial use only. Although this data set has been developed by the NGA no warranty expressed or implied is made by them as to the accuracy of the data and related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the NGA in the use of this data, or related materials.
- Status
- Complete
- Maintenance and Update Frequency
- Biennial
- Point of Contact
- Contact Organization
- National Geospatial-Intelligence Agency
- Delivery Point
- Office of Corporate Relations
- Delivery Point
- Public Affairs Division, MS D-54
- Delivery Point
- 4600 Sangamore Road
- City
- Bethesda
- State
- MD
- Postal Code
- 20816-5003
- Country
- USA
- Contact Telephone
- 800-455-0899
- Hours of Service
- Monday through Friday 9:00 A.M. to 4:00 P.M. EST-USA
- Credit
- National Imagery and Mapping Agency (now known as National Geospatial-Intelligence Agency).
- Native Data Set Environment
- Microsoft Windows 2000 Version 5.0 (Build 2195) Service Pack 4; ESRI ArcCatalog 9.0.0.535
- Data Quality Information
- Attribute Accuracy Report
- 100 percent of attribute codes were reviewed against the source manuscripts. No formal effort was undertaken to develop a quantitative attribute accuracy statement.
- Logical Consistency Report
- All data were found to be topologically correct. No duplicate features are present. All areas are completely described as depicted on the source manuscripts. No undershoots or overshoots are present. All data were consistently captured using the rules described in the narrative associated with the Data Quality Table and in the various feature table narrative files present at the coverage level within the library. Special automation techniques The DQNET coverage was created by determining the effective boundaries of each ONC source map and key-entering the coordinates into a digital file. These coordinates were used to generate line features which were then used to create polygon topology using the ARC BUILD command. ONC sheet identifiers were manually assigned to the areas. Text features were derived directly from the source charts, or were added separately, based on observations made during the automation process. Feature coincidence DQNET polygon features correspond to the effective data areas of each ONC source chart. For this reason, they are directly correlated with seams in the data. These boundaries are manifested as edgematching problems because of varying data densities, and cartographic decision rules. The line and polygon feature classes contain instances where sections of DQNET coverage boundaries are used to maintain connectivity and/or polygon closure for features in other layers. Database design issues The DQNET coverage is the only coverage with related attribute tables. These were created to maintain one-to-many relationships between feature primitives and some of their attributes
- Completeness Report
- 100 percent of features depicted on the ONC source materials have been captured. 100 percent of the features have valid attribute codes assigned to them. Airport features were derived from the DMA Digital Aeronautical Flight Information File (DAFIF). Where DAFIF was incomplete, locations were added from the ONC.
- Horizontal Positional Accuracy Report
- The Horizontal Positional Accuracy Value represents overall accuracy. Source chart-specific accuracies are available as area feature attributes in the VMap-0 data quality coverage. The primary accuracy analysis was performed on one chart only in the prototyping phase of the DCW project. Horizontal Positional Accuracy is expressed in meters. Detailed horizontal accuracy figures were developed by comparing the positions of well-defined points in the roads, railroads, utility lines, and drainage coverages 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 accuracies in a root sum square calculation.
- Quantitative Horizontal Positional Accuracy Assessment
- Lineage
- Source
- Originator
- National Imagery and Mapping Agency
- Publication Date
- 1974-1992
- Title
- Operational Navigational Chart (ONC)
- Geospatial Data Presentation Form
- map
- Publication Information
- Source Scale Denominator
- 1000000
- Type of Source Media
- stable-base material
- Source Temporal Extent
- Time Period Information
- Range of Dates/Times
- Beginning Date
- 1974
- Ending Date
- 1992
- Source Currentness Reference
- ground condition
- Contribution
- All information found on the source with the exception of aeronautical data. The U.S. Defense Mapping Agency Operational Navigation Chart (ONC) series and the Jet Navigation Charts (JNCs) for the region of Antarctica were the primary sources for the Digital Chart of the World database. The ONCs have a scale of 1:1,000,000, and they are the largest scale, unclassified map series produced by the DMA that provides consistent, continuous global coverage of essential basemap features. Some collateral sources have been used to enhance road and railroad connectivity through selected urbanized areas. The DMA's Digital Aeronautical Flight Information File (DAFIF) was the primary source for the airport data in the aeronautical layer. An Advanced Very High Resolution Radiometer (AVHRR) image for the coterminous United States is the source for the data in the Vegetation layer. The Defense Intelligence Agency Manual (DIAM) 65-18 is the source for the Geopolitical codes and the ocean boundaries information contained in the Political and Oceans layer. The product specifications for the ONCs and JNCs have been used extensively in the design of the database.
- Source
- Originator
- National Imagery and Mapping Agency
- Publication Date
- 199006
- Title
- Digital Aeronautical Flight Information File
- Publication Information
- Type of Source Media
- magnetic tape
- Source Temporal Extent
- Time Period Information
- Single Date/Time
- Calendar Date
- 1990
- Source Currentness Reference
- publication date
- Contribution
- Airport records (name, International Civil Aviation Organization, position, elevation, and type)
- Source
- Originator
- Defense Mapping Agency
- Publication Date
- 1990
- Title
- Jet Navigational Chart
- Geospatial Data Presentation Form
- map
- Publication Information
- Source Scale Denominator
- 2000000
- Type of Source Media
- stable-base material
- Source Temporal Extent
- Time Period Information
- Range of Dates/Times
- Beginning Date
- 1974
- Ending Date
- 1991
- Source Currentness Reference
- publication date
- Source
- Originator
- USGS EROS Data Center
- Title
- Advance Very High Resolution Radiometer
- Geospatial Data Presentation Form
- remote-sensing image
- Publication Information
- Source Scale Denominator
- 1000000
- Type of Source Media
- magnetic tape
- Source Temporal Extent
- Time Period Information
- Range of Dates/Times
- Beginning Date
- 199003
- Ending Date
- 199011
- Source Currentness Reference
- publication date
- Spatial Data Organization Information
- Direct Spatial Reference Method
- Vector
- Point and Vector Object Information
- SDTS Terms Description
- SDTS Point and Vector Object Type
- G-polygon
- Point and Vector Object Count
- 3573
- Spatial Reference Information
- Horizontal Coordinate System Definition
- Geographic
- Latitude Resolution
- 0.000001
- Longitude Resolution
- 0.000001
- Geographic Coordinate Units
- Decimal degrees
- Geodetic Model
- Horizontal Datum Name
- D_WGS_1984
- Ellipsoid Name
- WGS_1984
- Semi-major Axis
- 6378137.000000
- Denominator of Flattening Ratio
- 298.257224
- Vertical Coordinate System Definition
- Altitude System Definition
- Altitude Datum Name
- Mean Sea Level
- Altitude Resolution
- 1.000000
- Altitude Distance Units
- 1.0
- Altitude Encoding Method
- Explicit elevation coordinate included with horizontal coordinates
- Entity and Attribute Information
- Entity Type
- Entity Type Label
- DCW Data Quality Polygons
- Entity Type Definition
- Area features with associated data quality attributes
- Entity Type Definition Source
- HGL
- Attributes
- DQ_
- Internal feature number. (Sequential unique whole numbers that are automatically generated.)
- Definition Source
- ESRI
- DQ_ID
- User-defined feature number.
- Definition Source
- ESRI
- AFT_ID
- DQPYSID
- Data quality sheet identifier.
- Definition Source
- ESRI
- Attribute Value Accuracy
- ONC sheets are specified with a letter and two numbers, (e.g., G18 and E14). JNC sheets are specified with a number only (e.g., 120 for JNC120).
- DQPYCOM_DATE
- The compilation date of the source ONC sheet (excluding aeronautical and vegetation data)
- Definition Source
- ESRI
- DQPYCOM_TIME
- The compilation time of the source ONC sheet (excluding aeronautical and vegetation data)
- Definition Source
- ESRI
- DQPYREV_DATE
- The date of the last revision of the ONC source sheet.
- Definition Source
- ESRI
- DQPYREV_TIME
- The time of the last revision of the ONC source sheet.
- Definition Source
- ESRI
- DQPYLIT_DATE
- The lithograph or print date of the current revision.
- Definition Source
- ESRI
- DQPYLIT_TIME
- The lithograph or print time of the current revision.
- Definition Source
- ESRI
- DQPYREM
- Remarks or comment field containing sheetwide marginalia or observed characteristics, (i.e. "All roads are approximate alignment.").
- Definition Source
- ESRI
- DQPYAHA
- Absolute horizontal accuracy for ONC module areas.
- Definition Source
- ESRI
- Attribute Value Accuracy
- The value contained here is the root sum square of DMA-supplied individual ONC or JNC sheet horizontal error, plus the figures associated with the Digital Chart of the World production process. This figure is expressed in feet at 90 percent confidence level for circular error
- DQPYAVA
- Absolute vertical accuracy for ONC module areas.
- Definition Source
- ESRI
- Attribute Value Accuracy
- The value contained here is the root sum square of DMA-supplied ONC or JNC sheet vertical error, plus the figures associated with the Digital Chart of the World production process. This figure is expressed in feet at 90 percent confidence level for linear error.
- TILE_ID
- VPF Format Tile Identifier Code
- Definition Source
- NIMA
- SHAPE
- Feature geometry. (Coordinates defining the features.)
- Definition Source
- ESRI
- SHAPE.AREA
- Feature area measured in square map units
- Definition Source
- Computed
- SHAPE.LEN
- Polyline length measured in map units
- Definition Source
- Computed
- SHAPE.FID
- Internal feature number. (Sequential unique whole numbers that are automatically generated.)
- Definition Source
- ESRI
- Distribution Information
- Format Name
- Shape
- Distributor
- Harvard Geospatial Library
- Name
- Metadata Reference Information
- Metadata Date
- 20041116
- Metadata Contact
- Contact Information
- Contact Organization Primary
- Contact Organization
- Harvard Geospatial Library
- Contact Person
- Geospatial Resources Cataloger
- Contact Address
- Address
- Harvard University Library
- Address
- Office For Information Systems
- Address
- 1280 Massachusetts Avenue
- City
- Cambridge
- State or Province
- MA
- Postal Code
- 02138
- Country
- USA
- Contact Voice Telephone
- 617-495-2417
- Contact Facsimile Telephone
- 617-496-0440
- Contact Electronic Mail Address
- hgl_ref@hulmail.harvard.edu
- Hours of Service
- Monday - Friday, 9:00 am - 4:00 pm EST-USA
- Metadata Standard Name
- FGDC Content Standards for Digital Geospatial Metadata
- Metadata Standard Version
- FGDC-STD-001-1998
- Metadata Extensions
- Online Linkage
- http://www.esri.com/metadata/esriprof80.html
- Profile Name
- ESRI Metadata Profile
