Broad-scale land condition monitoring using Landsat TM and DEM-derived data.

We describe a project that is monitoring land condition in the south west of Western Australia using Landsat Thematric Mapper satellite images and terrain data derived from digital elevation models (DEMs). Land Monitor is a multi-agency project of the Western Australian Salinity Action Plan supported by the Natural Heritage Trust. The focus of the project is on broad-scale monitoring of land condition for environmental mangement at both catchment and policy levels. Land Monitor will provide land managers and administrators with baseline salinity and vegetation data for monitoring changes over time, and accurate land height data. Land Monitor will cover the 18 million hectares of agricultural land of south west Western Australia. Sequences of calibrated Landsat Thematic Mapper satellite images integrated with landform information derived from height data, ground truthing and other existing mapped data sets are used as the basis for monitoring changes in salinity and woody vegetation. Heights are derived on a 10m grid from stereo aerial photography flown at 1:40,000 scale, using softcopy automatic terrain extraction techniques. Land Monitor products will include salinity maps, enhanced imagery, vegetation status maps and spectral / temporal statistics. These products will be available in a range of formats and scales, from paddock, farm to catchment and regional scales.