Coastal Bend Texas Benthic Habitat Mapping Patchy Shapefile Map - San Antonio Bay and Espiritu Santo Bay (NODC Accession 0070784)

The original 1m DOQQs for the project area were resampled to 2m and mosaicked into a single four-band image. Image segmentation was performed using Definiens Professional. The classification of the habitat segments(as ESRI polygon shapefiles) was performed using CART analysis. The habitat map was refined with the aid of field data collected during May and July of 2008. The final habitat shapefile clipped to the final project area boundary. Each polygon has a unique polygon identification number in the attribute table (field"POLY_ID"). The final shapefile was checked for proper topology and to insure that each polygon has a correct habitat label, habitat code, modifier label if present, unique identification number, and an area calculation. Polygons below the 100m2 minimum mapping unit (MMU) were eliminated, though some polygons less than 100m2 were retained if their area changed to below the MMU due to the polygon boundary smoothing process. The habitat data also went through a independent validation review.Polygons in the habitat map labeled as Patchy SRV(seagrass) were used to mask the 2m mosaic for further classification of these areas. Pixels in the imagery falling within the Patchy SRV polygons were classified into a"percent seagrass" cover category using NDVI values.Pixels were classified into the following seagrass coverage categories:0% greater than 0-10% greater than 10-20% greater than 20-30% greater than 30-40% greater than 40-50% greater than 50-60% greater than 60-70% greater than 70-80% greater than 80-90% greater than 90%For each Patchy SRV polygon from the habitat map, the average percent seagrass coverage and standard deviation was calculated based on the coverage values of each pixel within the polygon. These data were included in the Patchy SRV shapefile attribute table.