This function returns the index of the raster image named gr_name for the HDF GR interface identified by the parameter gr_id.
The value of index can be passed into HDF_GR_SELECT to obtain the raster image identifier (ri_id).
Result = HDF_GR_NAMETOINDEX(gr_id, gr_name)
Returns the index of the raster image if successful or FAIL (-1) otherwise.
HDF_GR_ interface identifier returned by HDF_GR_START.
Name of the raster image.