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NC 1998 Color-Infrared Digital Orthophoto Quarter-Quadrangles (DOQQ)

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Abstract: Orthophotos combine the image characteristics of a photograph with the geometric qualities of a map. The primary digital orthophotoquad (DOQ) is a 1-meter ground resolution, quarter-quadrangle (3.75-minutes of latitude by 3.75-minutes of longitude). The geographic extent of the DOQ is equivalent to a quarter-quad plus the overedge ranges from a minimum of 50 meters to a maximum of 300 meters beyond the extremes of the primary and secondary corner points. The overedge is included to facilitate tonal matching for mosaicking and for the placement of the NAD83 and secondary datum corner ticks. The normal orientation of data is by lines (rows) and samples (columns). Each line contains a series of pixels ordered from west to east with the order of the lines from north to south. The standard, archived digital orthophoto is formatted as four ASCII header records, followed by a series of 8-bit binary image data records. The radiometric image brightness values are stored as 256 gray levels ranging from 0 to 255. The metadata provided in the digital orthophoto contain a wide range of descriptive information including format source information, production instrumentation and dates, and data to assist with displaying and georeferencing the image.
Purpose: DOQ's serve a variety of purposes, from interim maps to field references for earth science investigations and analysis. The DOQ is useful as a layer of a geographic information system and as a tool for revision of digital line graphs and topographic maps.
Supplemental Information: Filesizes vary. Approximate filesize (of compressed MrSID imagery is 7 MB.
Publication Date: 20040324
Originator: US Geological Survey
Publisher: DENR, Center for Geographic Information and Analysis
Time Period of Content:
Time Period Information:
Range of Dates/Times:
Beginning Date: 19940222
Ending Date: present
Currentness Reference: ground condition
Progress: In work
Maintenance and Update Frequency: irregular
Spatial Domain:
Bounding Coordinates:
West Bounding Coordinate: -84.5
East Bounding Coordinate: -75.6
North Bounding Coordinate: 36.5
South Bounding Coordinate: 33.75
Grid Coordinate System Name: State Plane Coordinate System 1983
Horizontal Datum Name: North American Datum 1983
Planar Distance Units: meters
Ellipsoid Name: Geodetic Reference System 1980
Distribution Liability: NCCGIA is charged with the development and maintenance of NC OneMap and, in cooperation with other mapping organizations, is committed to offering its users accurate, useful, and current information. Although every effort has been made to ensure the accuracy of information, errors and conditions originating from physical sources used to develop this dataset may be reflected in the data supplied. The user must be aware of possible conditions and bear responsibility for the appropriate use of the information with respect to possible errors, original map scale, collection methodology, currency of data, and other conditions specific to certain data. NCCGIA does not support secondary distribution of this dataset without its current, compliant metadata record. The use of trade names or commercial products does not constitute their endorsement by NCCGIA or North Carolina State Government.
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