I'm new to StackExchange and to remote sensing. I am working with MOD13Q1 250m 16-day MVCs. My goal is to use NDVI time-series to classify cropping pattern and crop type, then link this data to water issues and rainfall. I am working with ENVI 5.1, which is also new to me. I have used the Modis Reprojeciton Tool to reproject and mosaic two MODIS tiles covering Sri Lanka. The data has been reprojected into WGS84_UTM_44N. I output the data as a GeoTiff and have successfully loaded this into ENVI.
Here's my question: the pixels in the reprojected/mosaicked raster for the NDVI band (which is what i will need for the time-series analysis) run from -32768 to 32767, not from -1 to 1. Is this just some silly misinterpretation on my part, do I need to manipulate the raster somehow with ENVI, or have I distorted the data when reprojecting it?