SDA_SDA will store an index and data array in an SDA format file. The data array can be byte, integer*2, integer*4 or real*4. The dimensions of the image do not have to be the original dimensions. A sample is: IDL> sav_sda, outfil, index, data IDL> sav_sda, outfil, index, data, qswhere outfil is the name of the file you wish to store the data in. If you wish to append to an existing file, then you can use the /APPEND switch. For example: IDL> sav_sda, outfil, index, data, /appendUse RD_SDA to restore the data.