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Track: Natural Resources and Conservation
Steve Hartley
U.S. Geological Survey
700 Cajundome Boulevard
Lafayette, LA 70506
Telephone: 318-266-8543
Fax:
E-mail: hartleys@nwrc.gov
Jimmy Johnston, Pat O'Neil
Louisiana GAP Analysis Project: Usage of Auxiliary Data Sets
Good ancillary data sets are rare. Fortunately, Louisiana is blessed with an abundance of good quality auxiliary data sets. The most important of these data sets is the National Wetlands Inventory data, which cover approximately one-third of the southern half of the State. The Louisiana GAP Project is using these data in conjunction with Thematic Mapper (TM) imagery to produce a vegetation map of the State. The merging of these two data sets is not arbitrarily straightforward. One must consider the origin and format of the two different data sets. One data set is vector (NWI) and produced by photointerpretation of aerial photography, and the other is raster (TM) from satellite imagery. In order to merge the two data sets, the NWI Cowardin classification scheme had to be reclassified to the Louisiana GAP classification scheme and converted from vector to a raster data format. This procedure allows the two different data sets to be merged into one; however, it does not take into account the spatial
resolution of the two different data sets or the temporal changes between the sets. Temporal changes were limited to change in upland forest evergreen and mixed categories along the merge line between the two different data sets. In order to accommodate these differences we had to subset the NWI upland forest evergreen and mixed categories and integrate TM imagery for further processing. The poster depicts several output steps used to produce the final merge of classified NWI and TM data sets. Other auxiliary data sets used in the Louisiana GAP vegetation classification include 1995 color infrared photography (CIR), SPOT data, and ground truthing data. These data sets are of significant help to classify the TM imagery.
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