In the list of raster pixel data types that are available with GDAL, the "smallest" types are Bytes, UInt16 and Int16. I would like to store integers from 0 to 100 in the smallest image type, but with the constraint of using -1 and -2 for NoData value and other specific value. GDAL Bytes are unsigned, so the smallest type would be Int16. http://www.gdal.org/gdal_8h.html#a22e22ce0a55036a96f652765793fb7a4
I use this type to create rasters, with the Rasterize function in Python bindings.
Do you know if there is a trick to use signed Bytes ?