Importing and displaying SPOT imagery from CD-ROM

[Felix Gershunov]

 Hi!
 
> I have a problem to extract and display SPOT scenes in original data
> format from CD-ROM:
> When I try to extract SPOT imagery data from CD-ROM with i.tape.other
> the extraction process seems to work well on a first view, but when I
> try to display the scene, e.g. by d.rast, the output is only a noisy
> arrangement of pixels. Can anybody help me?
> Thanks
> Mark
> 
 I had done such task nearly a year ago, and now I do not fully remember 
the way I did it, but at that time Karl Nissen had written to me a nice 
letter that will help you, I think:
===

Felix,

It appears that you need to use i.tape.other to import the data, I haven't 
used this application, but I would assume that it will ask you during the 
import for the number of bands, number of lines, number of columns, and 
optionally if you want to skip header bytes.

First get the size of the image file in bytes and find out if the image is 
panchromatic or multispectral. I'm assuming that you have a standard SPOT 
full scene product.

If panchromatic there should be 6001 lines of imagery, if multispectral 
9001. The additional line (6000 lines of imagery + 1 header line, 3 bands 
* 3000 lines of imagery + 1 header line) is a header record.

Divide the image size by the number of lines. This should give you the 
number of columns. This number should be whole (no fraction).

You should now have the number of lines per band (6000 or 3000) number of 
bands (1 or 3), number of columns and you want to skip the first record 
(imagery starts on line 2). If you don't do this for multispectral data 
the bands will not be coregistered (band 1 wil be shifted down a line with 
respect to bands 2 and 3).

The file format is band interleaved (BIL).

===
                                            Felix.