Coastal Bend Texas Benthic Habitat Mapping Reprocessed DOQQ Aerial Imagery

Custom download app allowing subsetting and format/projection changes of the color infrared imagery

Custom download app for the natural color imagery

Imagery files for color infrared

download site for the natural color imagery

Date that the source FGDC record was last modified.

Converted from FGDC Content Standard for Digital Geospatial Metadata (version FGDC-STD-001-1998) using 'fgdc_to_inport_xml.pl' script. Contact Tyler Christensen (NOS) for details.

Partial upload of Positional Accuracy fields only.

Partial upload to move data access links to Distribution Info.

TerraSurv, Inc. of Pittsburgh, PA was contracted by EarthData International of Frederick, MD to perform a geodetic control survey in support of mapping an area along the southeasterly coast of Texas between Port Lavaca and Brownsville. Thirty-eight photo identifiable locations were surveyed to provide ground control and quality assurance checks for the mapping. Twenty of the stations were used for mapping control and eighteen of the stations were used for quality checks. The horizontal datum was the North American Datum of 1983, CORS adjustment (NAD 1983 CORS). The vertical datum was the North American Vertical Datum of 1988 (NAVD 1988). | Source Geospatial Form: model | Type of Source Media: paper

The digital orthophotography was developed from imagery acquired at a resolution of 0.9 meters as part of the 2004 overflight of the State of Texas developed for the USDA National Agricultural Imagery Program (NAIP). In order to achieve a horizontal accuracy of 5 meters, CE90 it was necessary to reprocess the imagery incorporating new GPS field control. It should be noted that the imagery was not tide coordinated so tidal variation may exist between sorties. The imagery was acquired between November 3, 2004 and November 7, 2004. 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) to allow stereo viewable imagery. This stereo viewable imagery was processed with the GPro/LPS automatic point matching algorithm to determine common match points every 2000 pixels across the imagery strip and 333 pixels along strip. This pattern included dual rows of line ties to the adjacent line of imagery. The resulting point data was imported into Leica ORIMA and used to perform a full bundle adjustment of the imagery point data. Any blunders were removed, and weak areas were manually supplemented to ensure good coverage of points. TerraSurv, Inc. of Pittsburgh, PA was contracted by EarthData International of Frederick, MD to perform a geodetic control survey in support of mapping an area along the southeasterly coast of Texas between Port Lavaca and Brownsville. Thirty-eight photo identifiable locations were surveyed to provide ground control and quality assurance checks for the mapping. Twenty of the stations were used for mapping control and eighteen of the stations were used for quality checks. The horizontal datum was the North American Datum of 1983, CORS adjustment (NAD 1983 CORS). The vertical datum was the North American Vertical Datum of 1988 (NAVD 1988). These control points were incorporated into the ORIMA bundle adjustment to ensure absolute accuracy requirements were met. The 18 quality check points coordinates were solved for in the bundle adjustment and compared to the surveyed results. 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 NED DEM. The 10m NED DEM was used where available and 30m DEM was used elsewhere. The orthorectified image strips were processed with a internally developed routine 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. These final DOQQ sheets contained a 300m minimum buffer. The sheets for the project area were then resampled to 2m and mosaicked. For habitat classification, the mosaicked imagery was divided into six processing one set of six mosaics for true color and one set of six mosaics for color-IR. Image segmentation was performed using on the blue, green, red, and near-infrared bands for each of the six processing areas.