geostationary satellite data

[Peter Pearson]

On Wed, 16 Dec 2015 13:19:26 -0200, jorge.conrado at cptec.inpe.br wrote:
>
> I dowmloaded some data from the Mirador NASA site:
>
> http://mirador.gsfc.nasa.gov/cgi-bin/mirador/presentNavigation.pl?tree=project&dataset=Global-merged%20IR%20Brightness%20Temperature%20Data&project=TRMM&dataGroup=Ancillary&version=001&CGISESSID=97f4b9244878c87819b2a1144d31e270
>
> Each data have the dimension:  9896 x 3298 byte.
>
> I used to read the command :
>
> f = open('merg_2015110500_4km-pixel', mode='rb')
>
> image = f.read()
>
> Please, what can I do to visualize this data.

You provide a URL to a web page, but you're opening a file.  Can
you tell us what kind of file you downloaded?

I grabbed a random file from that site, and it arrived with the name
"merg_2015120123_4km-pixel.Z".  After I ran "uncompress" on it, it was
named "merg_2015120123_4km-pixel", which looks much like your filename,
so I guess this is what you've done.  When I dump it as bytes, I get
a lot of this:

00000100  ff ff c0 c0 c1 c2 c2 c2  c2 c3 c3 c3 c3 c4 c4 c3
00000110  c3 c3 c1 c1 c0 c0 ff ff  ff ff ff ff ff ff c1 c1
00000120  c3 c4 c4 c4 c3 c3 c3 c3  c1 ff ff ff ff ff ff ff
00000130  ff ff ff ff ff ff ff ff  ff ff ff ff ff ff ff ff
00000140  ff ff ff ff ff ff ff c0  c0 c1 c3 c3 c3 c3 c4 c4
00000150  c4 c4 c4 c3 c3 c3 c4 c4  c3 c3 c3 c3 c3 c3 c3 c3
00000160  c4 c4 c4 c4 c4 c5 c5 c6  c7 c7 c7 c7 c5 c5 c5 c6
00000170  c6 c6 c6 c6 c4 c4 c4 c4  c4 c3 c3 c3 c3 c3 c3 c3
00000180  c2 c2 c2 c3 c3 c3 c4 c4  c4 c4 c4 c4 c4 c5 c5 c6
00000190  c6 c6 c6 c6 c6 c7 c7 c7  c7 c7 c7 c7 c7 c7 c7 c7
000001a0  c7 c7 c7 c8 c8 c8 c8 c8  c9 c9 c9 c9 c9 c9 c9 c9

The file is 65274016 bytes long.  You claim the dimensions are
9896 x 3298, but that comes out to half that number (32637008), so I'll
bet the real dimensions are 9896 x 6596, with one byte per pixel.
I think this image format is called "raw".

I haven't the time and expertise to settle this for you, but
the solution is probably going to look something like this:

>>> rawdata = open("merg_2015120123_4km-pixel", "rb").read()
>>> from PIL import Image
>>> img = Image.fromstring("L", (9896, 6596), rawdata)
>>> img.save("temp.png")


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