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Central African Republic, Chad, Democratic Republic of the Congo, Republic of the Congo, Sudan, Uganda, 1988, Operational Navigation Chart (ONC) L-4 (Raster Image)
- 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
- Aerospace Center (U.S.)
- Originator
- United States. National Imagery and Mapping Agency.
- Originator
- United States. Defense Mapping Agency.
- Originator
- Harvard University. Center for Geographic Analysis.
- Originator
- East View Cartographic, Inc.
- Publication Date
- 2009
- Title
- Central African Republic, Chad, Democratic Republic of the Congo, Republic of the Congo, Sudan, Uganda, 1988, Operational Navigation Chart (ONC) L-4 (Raster Image)
- Geospatial Data Presentation Form
- map
- Publication Information
- Publication Place
- Cambridge, Massachusetts
- Publisher
- Harvard Map Collection, Harvard College Library
- Online Linkage
- https://hgl.harvard.edu/catalog/harvard-am-onc-l04l
- Abstract
- This layer is a georeferenced raster image of the United States Aerospace Center's Operational Navigation Chart (ONC) 1:1,000,000 map series sheet entitled: ONC L-4 : Central African Republic, Chad, Congo, Sudan, Uganda, Zaire. Edition: 4. Revision date: 1988. Printed in: 2003. Covers all or portions of: Central African Republic, Chad, Democratic Republic of the Congo, Republic of the Congo, Sudan, Uganda. The image inside the map neatline is georeferenced to the surface of the earth and fit to World Geodetic System (1984) coordinates. All map collar information is also available as part of the raster image. Series source sheets are of varying revision dates (1979-1998) and editions, published by the U.S. Defense Mapping Agency/U.S. National Imagery and Mapping Agency (later the National Geospatial-Intelligence Agency). The source map was scanned and georeferenced for Harvard University's Center for Geographic Analysis' AfricaMap project by East View Cartographic. Individual ONC sheets covering Africa (47 sheets in total) were selected from the worldwide ONC series. The ONC is the standard worldwide small-scale aeronautical chart series, and contains cartographic data with an aeronautical overprint depicting obstructions, aerodromes, special use airspace, navigational aids, Maximum Elevation Figures (MEFs), and related data. ONC's also show selected topographic, cultural and hydrographic features such as: city outlines, towns and villages, rivers, lakes, landmark features (labeled), roads, railroads, towers, transmission lines, vegetation areas, clearings, and more. Ground elevation is indicated by contours (1000-foot intervals with 250-foot auxiliary contours), shading, tints, and spot heights. Please pay close attention to map collar information for original projection information, keys and legends to grid and chart numbering and other numbers, elevations, aeronautical information, vertical obstacles, ground cover, cultural features, and other data which appear inside the neatline.
- Purpose
- ONCs are designed for medium altitude (2,000 to 25,000 feet above ground level) high-speed visual and radar navigation. Also used for mission planning/analysis and intelligence briefings, and are source for navigational filmstrips, special purpose, and cockpit/visual display products. In the absence of TPCs, ONCs also satisfy enroute visual and radar navigation requirements for low altitude operations. The wide range of information provided on these maps make them useful in the study of historic geography, and urban and rural land use change. As this map has been georeferenced, it can be used in a GIS as a source or background layer in conjunction with other GIS data.
- Temporal Extent
- Currentness Reference
- source map ground condition
- Time Instant
- 1988
- Bounding Box
- West
- 16.915415
- East
- 30.171133
- North
- 8.295335
- South
- -1.307164
- Theme Keyword
- Maps
- Aeronautical charts
- Landforms
- Bodies of water
- Human settlements
- Land use
- Infrastructure
- Transportation
- Theme Keyword Thesaurus
- LCSH
- ISO Topic Category
- imageryBaseMapsEarthCover
- transportation
- Place Keyword
- Central African Republic
- Chad
- Congo, Democratic Republic of the
- Congo, Republic of the
- Sudan
- Uganda
- Place Keyword Thesaurus
- GNS
- Temporal Keyword
- Access Restrictions
- None
- Use Restrictions
- For educational, non-commercial use only.
- Status
- Complete
- Maintenance and Update Frequency
- None planned
- Point of Contact
- Contact Organization
- Center for Geographic Analysis
- Delivery Point
- Harvard University
- Delivery Point
- CGIS K-00A
- Delivery Point
- CGIS Knafel Building
- Delivery Point
- 1737 Cambridge St.
- City
- Cambridge
- State
- MA
- Postal Code
- 02138
- Country
- USA
- Contact Electronic Mail Address
- contact@help.cga.harvard.edu
- 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
- The georeferenced raster is a faithfully reproduced digital image of the original source map. Some differences may be detected between the source graphic used and the raster image due to the RGB values assigned that particular color. The intent is to recreate those colors as near as possible. In regard to the source maps: The representation of boundaries are not necessarily authoritative.
- Logical Consistency Report
- Not applicable.
- Completeness Report
- Data completeness for raster image files reflect content of the source graphic. Features may have been eliminated or generalized on the source graphic due to scale and legibility constraints. For instance with ONCs because of scale, some features, including obstructions, are generalized in developed regions (only the highest obstruction within ticked area or urban quadrant is shown).
- Horizontal Positional Accuracy Report
- The horizontal positional accuracy of a raster image is approximately the same as the accuracy of the published source map. The lack of a greater accuracy is largely the result of the inaccuracies with the original measurements and possible distortions in the original paper map document. There may also be errors introduced during the digitizing and georeferencing process. In most cases, however, errors in the raster image are small compared with sources of error in the original map graphic. While the data of the published map is retained in the georeferenced image, the image is referenced to the World Geographic Reference 1984 system, which is inconsistent with the original projection of the paper map, and may lead to discrepancies in the horizontal accuracy of the raster image. The Root Mean Square (RMS) error for this map is 97.6796 meters. This value describes how consistent the transformation is between the different control points (links). The RMS error is only an assessment of the accuracy of the transformation.
- Quantitative Horizontal Positional Accuracy Assessment
- Lineage
- Source
- Originator
- Aerospace Center (U.S.)
- Originator
- United States. National Imagery and Mapping Agency.
- Originator
- United States. Defense Mapping Agency.
- Publication Date
- 2003
- Title
- ONC L-4 : Central African Republic, Chad, Congo, Sudan, Uganda, Zaire
- Edition
- Ed. 4
- Geospatial Data Presentation Form
- map
- Collection Title
- Operational navigation chart, ONC, [Africa]
- Series Information
- Series Name
- ONC
- Issue Identification
- L-4
- Publication Information
- Publication Place
- St. Louis, Mo.
- Publisher
- Defense Mapping Agency
- Source Scale Denominator
- 1000000
- Type of Source Media
- paper
- Source Temporal Extent
- Time Period Information
- Single Date/Time
- Calendar Date
- 1988
- Source Currentness Reference
- ground condition
- Contribution
- Original map was scanned and georeferencing.
- Spatial Data Organization Information
- Direct Spatial Reference Method
- Raster
- Raster Object Information
- Raster Object Type
- Pixel
- Row Count
- 16691
- Column Count
- 23041
- Vertical Count
- 1
- 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
- Entity and Attribute Information
- Entity and Attribute Overview
- The indexes reference a color palette of RGB values from 0 through 255, representing the color value from the original paper sheet map. The colors on that sheet represent relief, drainage, vegetation, populated places, cultural features, coastal hydrography, transportation features (roads, railroads, tracks and trails), spot elevations and national and international boundaries. The colors are explained in a legend that is incorporated into the map collar.
- Entity and Attribute Detail Citation
- Not applicable.
- Distribution Information
- Format Name
- JPEG2000
- Distributor
- Harvard University Library
- Online Access
- http://hgl.harvard.edu/
- Name
- Metadata Reference Information
- Metadata Date
- 20090618
- Metadata Contact
- Contact Information
- Contact Organization Primary
- Contact Organization
- Harvard Geospatial Library
- Contact Position
- Geospatial Resources Cataloger
- Contact Address
- Address
- Harvard University Library
- Address
- Office For Information Systems
- Address
- 90 Mount Auburn Street
- 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
