Investigations of possible contributions NDVI's have to misclassification in AVHRR data analysis

Numerous subcontinental-scale projects have placed significant emphasis on the use of Normalized Difference Vegetation Indices (NDVI's) derived from Advanced Very High Resolution Radiometer (AVHRR) satellite data for vegetation type recognition. In multi-season AVHRR data, overlap of NDVI ranges for vegetation classes may degrade overall classification performance. The preliminary work of this project is presented to illustrate potential differences in vegetative cover discrimination capabilities between original visible and near-infrared (NIR) channels of AVHRR data and NDVI's derived from these channels. Initial tests on AVHRR data have been performed for regions of known vegetative cover composition in Northern Mexico. The results are presented here to stimulate debate on the effectiveness of use of NDVI's for vegetation type discrimination.