Imagery data for the Vegetation Mapping Inventory Project of Big Bend National Park

This reference contains the imagery data used in the completion of the baseline vegetation inventory project for the NPS park unit. Orthophotos, raw imagery, and scanned aerial photos are common files held here.

To complete the automated phase, CTI subcontracted with Photo Science (based in Lexington, KY) to create a BIBE landform layer and a drainage/wash layer. Photo Science reviewed and acquired all National Elevation Dataset (NED) 10-meter DEMs for the project area and mosaiced them into a seamless coverage. The DEM data was then manipulated to create the following derived spatial layers: aspect, slope, three hillshade datasets (different azimuth angles), a contour range layer, and a compound topographic index (or wetness index) that models water flow and accumulation. Similarly, Photo Science also acquired the 2012 National Agriculture Imagery Program (NAIP) imagery for the entire project area as high-resolution (1-meter pixels) digital ortho quarter quadrangles (DOQQs). The NAIP DOQQs were mosaiced and resampled from 1-meter to 10-meter pixels to match the DEM resolution. Erdas Imagine software was then used to derive a normalized difference vegetation index (NDVI) and a near infrared (NIR) band texture layer from the imagery using a 9x9 moving window. During the planning and coordination phase, CTI staff reviewed all available digital imagery for its potential use as the BIBE basemap. The most promising and easy to access was the data catalog found on the Texas Natural Resource Information System (TNRIS) website. Navigating to the orthoimagery-statewide web page, the list of existing imagery covering BIBE included multiple NAIP products. The corresponding 2010 and 2012 NAIP 1-meter DOQQs for BIBE were downloaded and used during the early planning stages of this project and to produce field maps and interim products.