Unisys Satellite File

Unisys delivers satellite imagery in this format. Most Unisys imagery is un-navigated except for some lambert conformal images.  The xsat program can display the navigated images with a map overlay or the un-navigated images.   Pseudo-navigation can be added to these images with the grid_domain resource. 

FORMAT

The file is split up into 2 components:

1. Product header which contains simple navigation and product time. The header is ASCII data with the terminating "end" string.  The contents of the header include keyworded pieces of data. The keywords are:
   • hsxxx-- Header size in bytes (not reliable)
   • xxxx -- Image width in pixels
   • yxxx -- Image height in pixels
   • wrxxx -- Image width resolution
   • hrxxx -- Image height resolution
   • idxxx -- Sector name
   • bxxx -- Sensor band number
   • ssnxxx -- Start element number on scan line
   • slnxxx -- Start scan line number
   • esnxxx -- End element number on scan line
   • elnxxx -- End scan line number
   • srxxx -- Spot/element resolution
   • lrxxx -- Line resolution
   • bppxxx -- Bits per pixel
   • latxxx -- Central latitude
   • lonxxx -- Central longitude
   • ref1xxx -- Reference latitude
   • ref2xxx -- Reference longitude
   • ref3xxx -- True latitude #1
   • ref4xxx -- True latitude #2
   • fldxxx -- Date of image
   • end -- End of header
     
2. Pixel data (the rest of the file).  

EXAMPLES

Here is a lambert conformal image over the US:

hs223  x640 y448 idnav_ir b1 fld902803530
bpp8 pl piset0 gg
lat38.000000 lon-98.000000 range31.540000
ref138.000000 ref2-98.000000 ref333.000000 ref445.000000
maxrank255 CIL2 RIV2 PBY1 BDY1 res255
dlat0.00000000 dlon0.00000000     end
~~K5459;EUOD<9<@@=<;;?<47<=9:>965444444444444444665566676
...

Here is a un-navigated GOES image:

hs109 x1024 y1024 wr25000 hr25000 idful_di b1 ssn1420 sln324 
esn6241 eln1715 sr4 lr4 fld902805362 v10137 end
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...

SEE ALSO

• satplot

Last updated MAy 10, 2020