This data set contains a modified version of imagery from the National Agriculture Imagery Program (NAIP). The original APFO orthoimagery has been modified by the Arizona State Land Department ALRIS Program. The APFO TIFF quarterquads were mosaiked into 1/2 degree blocks (ALRIS Tiles), compressed (1:20) and reformatted as SID/SDW files. Tiles that were in UTM NAD83 Zone 11 were also reprojected into UTM NAD83 Zone 12. NAIP acquires digital ortho imagery during the agricultural growing seasons in the continental U.S. A primary goal of the NAIP program is to enable availability of ortho imagery within one year of acquisition.
NAIP imagery is available for distribution within 60 days of the end of a flying season and is intended to provide current information of agricultural conditions in support of USDA farm programs. For USDA Farm Service Agency, the 1 meter GSD product provides an ortho image base for Common Land Unit boundaries and other data sets. The 1 meter NAIP imagery is generally acquired in projects covering full states in cooperation with state government and other federal agencies who use the imagery for a variety of purposes including land use planning and natural resource assessment. With an annual cycle, NAIP is also used for disaster response often providing the most current pre-event imagery.
ground condition
Imagery may be replaced to address defects found in a small number of products through quality assurance processes. Imagery containing defects that require the acquisition of new imagery, such as excessive cloud cover, specular reflectance, etc., will not be replaced within a NAIP project year.
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NAIP Tile file names are based on the Arizona State Land Department ALRIS Tile naming convention.
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FSA Digital Orthophoto Specs.
Digital Georectifed Image.
Imagery was flown with Leica ADS40 digital sensors to capture 0.9m raw data. Raw data was then downloaded using Leica GPro software into 12 bit TIFF format. The raw TIFF imagery was then georeferenced and reprojected using GPS/INS 200Hz exterior orientation information (x/y/z/o/p/k). Technicians precisely measured ground control and tie points in 3 bands/looks (Back/Nadir/Forward) for each line. The resulting point data, ground control, and orientation data was used to perform a full bundle adjustment. Any blunders were removed, and weak areas were manually supplemented to ensure good coverage of points. Once the point data was cleaned, and point coverage was acceptable, control points from the prior generation MDOQQ's and source DEM were introduced in the corners and center of the block being adjusted. This control was used to perform any datum shift (x/y/z and rotation) to ensure the new adjusted imagery fitted the existing MDOQQ reference imagery. The output from this bundle adjustment process was revised exterior orientation data for the sensor with any GPS/INS, datum, and sensor calibration errors modeled and compensated for. Using this revised EO data orthorectified image strips were created using the USGS DEM. The 10m DEM was used where available and 30m DEM was used elsewhere. The orthorectified strips were overlaid with the existing MDOQQ compressed files to ensure accuracy was met by visual inspection and manually measuring features. Once the accuracy of the orthorectified image strips were validated the strips were processed with a NWG proprietary dodging package that compensates for the bi-directional reflectance function that is caused by the sun's position relative to the image area. This compensated imagery was then imported into Inpho's OrthoVista 4.0 package which was used for the final radiometric balance, mosaic, and DOQQ sheet creation.
The following processes were carried out with LizardTech GeoExpress software ( v.7): DOQQ TIFF files were mosaiked to conform to the ALRIS tile index structure (half-degree blocks). The mosaiked tiles were also buffered (2-4 miles) on all four sides where permissible. Some files were also reprojected from UTM NAD83 Zone 11 into UTM NAD83 Zone 12. Each mosaic was then compressed (1:20) and saved in a SID format (with accompanying SDW files).
Dataset copied.
Dataset moved.
Dataset copied.
Internal feature number.
ESRI
Feature geometry.
ESRI
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In no event shall the creators, custodians, or distributors of this information be liable for any damages arising out of its use (or the inability to use it).
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