PCI Geomatics' GCPWorks module was used to register the uncorrected TM scenes with Arkansas Highway and Transportation Department road vector data (UTM projection, NAD83 datum). A first order polynomial transformation model with nearest-neighbor resampling was used to rectify the image. The residual root mean square error was consistently less than one pixel on both the X and Y axes.

The twenty-seven county study area was divided into four groups roughly corresponding to TM path-row position. Group 1 (23/35 part of 24/35): Clay, Craighead, Greene, Independence, Jackson, Lawrence, Mississippi, Poinsett, Randolph counties. Group 2 (23/36): Arkansas*, Crittenden, Cross, Lee, Monroe*, Phillips, St. Francis, and Woodruff counties. Group 3 (23/37 parts of 23/36 and 24/37): Arkansas*, Ashley, Chicot, Desha, Drew, and Lincoln counties. Group 4 (24/36): Arkansas*, Jefferson, Lonoke, Monroe*, Prairie, Pulaski, and White counties. (* Training data for both Arkansas and Monroe counties were used in two or more groups in order to maximize available data. The final LULC maps for these counties come from the group classification which produced the best results: for both Monroe and Arkansas counties this was Group 4.

Upon inspecting the images for radiometric errors, several bright spots, flanked on both sides by rays of either maximum (255) or minimum (0) DN values were discovered in the mid IR bands of several scenes. The rays extended outwards horizontally as little as a few hundred meters to as much as several kilometers, and ranged from one to five pixels wide. It was discovered that these were fields which were being burned as the sensor passes over. These very bright spots (in bands 5 and 7) caused a calibration error. To correct this radiometric error, a binary masks for effected area was screen digitized, and an averaging filter was performed for pixels under the mask. Up to three iterations of the filtering process were needed to correct the calibration error. No radiometric corrections were made to adjust atmospheric conditions, or scene illumination (sun angle compensation).

(Before and After Averaging Filter: TM Band 7)