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Re: Importing Binary Images [message #29003 is a reply to message #28873]

Thu, 24 January 2002 07:56

rschick
Messages: 2
Registered: January 2002

Junior Member

rschick@neaq.org (rob schick) wrote in message news:<240cd6d2.0201180638.46419bb3@posting.google.com>...
> I'm new to idl, and am trying to import a binary grid that was created
> on a windows machine into idl on a linux machine. It's least
> significant byte first, 1561 rows, 2041 cols.
>
> I searched the archives and found a thread that suggested used the
> following syntax:
>
> IDL> openr, 1, 'gom15dd.dat'
> IDL> ms = bytarr(1561, 2041)
> IDL> readu, 1, ms
> IDL> tv, ms
>
> While this 'works', the image displayed is incorrect - sort of looks
> like speckled white noise. Any thoughts on what I may be doing wrong.
> For a newbie, what's the difference between using readu, and
> read_binary? The online help didn't help. Thanks.

Ok - thanks to all for the replies. The program creating the image, is
in row-major. I created the image on an NT machine, and am using IDL
on a linux machine (intel processor).

I tried
IDL> openr, 1, 'gom15dd.dat', /swap_if_little_endian
IDL> ms = intarr(2041,1561)
IDL> readu, 1, ms
IDL> tvscl, ms

and this looks better. I don't think it's quite correct, so my
questions as related to the suggestions are:

If my image is indeed not byte, do I do something different, e.g.
-rw-r--r-- 1 robs robs 12744004 Jan 17 14:38 gom15dd.dat
that value divided by (1561x2041) = 4 ?

Do I do anything differently to account for the row-major output?
(specifying columns first in the openr line made the image appear more
normal...

Thanks, Rob

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[Message index]

		Importing Binary Images By: rschick on Fri, 18 January 2002 06:38
		Re: Importing Binary Images By: Craig Markwardt on Fri, 18 January 2002 10:53
		Re: Importing Binary Images By: Martin Downing on Fri, 18 January 2002 09:05
		Re: Importing Binary Images By: Med Bennett on Fri, 18 January 2002 08:51
		Re: Importing Binary Images By: Nigel Wade on Thu, 24 January 2002 09:03
		Re: Importing Binary Images By: Craig Markwardt on Thu, 24 January 2002 09:06
		Re: Importing Binary Images By: Martin Downing on Tue, 29 January 2002 10:09
		Re: Importing Binary Images By: rschick on Thu, 24 January 2002 07:56

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