[fitsbits] question about imcopy.c

[shntn05 at gmail.com]

Thanks for the info. I have one question. When I look at the tile
compressed
image file with fv , how do I find out the value of ZSCALE and ZZERO
for each pixel?
In the original image  the values of the pixels  are 500.296875,
494.3046875
etc when I use fv to look at the image.
When I looked at the tiled compressed image, the vales for the same
are
-32267.6708622559 and -32273.7009830322. Obviously these have been
scaled from the original pixel values using ZSCALE and ZZERO. How do I
find out these values?
Here is what the header fir the tiled compressed image says :
TFIELDS =                    4 / number of fields in each row
TTYPE1  = 'COMPRESSED_DATA'    / label for field   1
TFORM1  = '1PB(10726)'         / data format of field: variable length
array
TTYPE2  = 'UNCOMPRESSED_DATA'  / label for field   2
TFORM2  = '1PE(0)  '           / data format of field: variable length
array
TTYPE3  = 'ZSCALE  '           / label for field   3
TFORM3  = '1D      '           / data format of field: 8-byte DOUBLE
TTYPE4  = 'ZZERO   '           / label for field   4
So presumably the values of ZSCALE and ZZERO are in the third and
fourth
field. But how do/can  I get these values for each pixel?
Any information on this will be appreciated.
Thanks