| Title | DOQQ Boundaries | | Date | 6/28/2002 | | Date Type | publication | | Edition | | | Organization Name | U.S. Geological Survey | |
Role
| originator | |
Presentation Form
| mapDigital | |
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) image cast on the Universal Transverse Mercator Projection (UTM) on the North American Datum of 1983 (NAD83).The geographic extent of the DOQ is equivalent to a quarter-quad plus The overedge ranges 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. The standard distribution format of DOQs will be JPEG compressed images on CD-ROM by counties or special regions. The reconstituted image from the CD-ROM will exhibit some radiometric differences when compared to its uncompressed original but will retain the geometry of the uncompressed DOQ. Uncompressed DOQs are distributed on tape. | |
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. | |
Status
| onGoing | |
Descriptive Keywords
| rectified photograph, DOQQ, 7.5- x 7.5-minute orthophoto, 1-meter orthophoto, digital orthophotoquad, aerial photograph, 2-meter orhtophoto, orthophoto, 3.75- x 3.75-minute orthophoto, rectified image, DOQ, quarter-quadrangle orthophoto, digital image map, digital orthophoto, Land Grids, FIPS code of State or Province, FIPS code for county or counties., MX, US, CA | |
Access Constraints
| otherRestrictions | |
Other Constraints
| access constraints: None | |
Use Constraints
| otherRestrictions | |
Other Constraints
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Language
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Topic Category Code
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Geographic Bounding Box
| | North bound latitude | | | 37 | | | West bound longitude | | East bound longitude | | -103.125 | | -94.375 | | South bound latitude | | | 33.5 | |
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Distribution Information
| | Name | USGS_DOQ | | Version | unknown | | Individual Name | | | Organization Name | Earth Science Information Center, U.S. Geological Survey | | Position Name | | | Voice | 1-888-ASK-USGS | | Facsimile | | | Address | | | City | Reston | | State | VA | | Postal Code | 20192 | | Country | | | Electronic mail address | | | Hours of Service | 0800-1600 | | Role | pointOfContact | | Fees | The cost for these CD-ROM products is available at: <URL:http://edcwww.cr.usgs.gov/glis/hyper/order_info/prices#DOQ_COUNTY> | | Ordering Instructions | Dataset searching and ordering capabilities are available through the Global Land Information System (GLIS) at: <URL:http://edcwww.cr.usgs.gov/webglis> | | Transfer Size | 5 |
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Spatial Representation Information
| | Geometric Object Type | complex | | Geometric Object Count | 5048 |
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Data Quality
| | Evaluation Method | All DOQ header data and image file sizes are validated by the Tape Validation System (TVS) software prior to archiving in the National Digital Cartographic Data Base (NDCDB). This validation procedure assures correct physical format and field values for header record elements. Logical relationships between header record elements are tested. | | Topological Consistency | | | Absolute Positional Accuracy | The DOQ horizontal positional accuracy and the assurance of that accuracy depend, in part, on the accuracy of the data inputs to the rectification process. These inputs consist of the digital elevation model (DEM),aerotriangulation control and methods, the photo source camera calibration, scanner calibration, and aerial photographs that meet National Aerial Photography Program (NAPP) standards. The vertical accuracy of the verified USGS format DEM is equivalent to or better than a USGS level 1 or 2 DEM, with a root mean square error (RMSE) of no greater than 7.0 meters. Field control is acquired by third order class 1 or better survey methods sufficiently spaced to meet National Map Accuracy Staandards (NMAS) for 1:12,000-scale products. Aerial cameras have current certification from the USGS, National Mapping Division, Optical Science Laboratory. Test calibration scans are performed on all source photography scanners. | | Attribute Accuracy | During photographic reproduction of the source photography, limited analog dodging is performed to improve image quality. Analog dodging consists of holding back light from certain areas of the sensitized photographic material to avoid overexposure. The diapositive is inspected to insure clarity and radiometric uniformity. Diapositive image brightness values are collected with a minimum of image quality manipulation. Image brightness values may deviate from brightness values of the original imagery due to image value interpolation during the scanning and rectification processes. Radiometry is verified by visual inspection of the digital orthophoto quadrangle with the original unrectified image to determine if the digital orthophoto has the same or better image quality as the original unrectified input image. Slight systematic radiometric differences can be detected between adjacent DOQ files due primarily to differences in source photography capture dates and sun angles of aerial photography along flight lines. These differences can be observed in an image's general lightness or darkness when compared to adjacent DOQ file coverages. | | Process Step | Metadata imported. | | Source | Elevation data in the form of an ortho-DEM regridded to user-specified intervals and bounds. | | Responsible Party | U.S. Geological Survey | | Role | originator |
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Metadata
| | Metadata Standard | ISO 19115:2003/19139 | | Version | 1.0 |
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