IDL
From Peyton Hall Documentation
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| - | + | IDL is a data visualization & analysis program used by many in the department. | |
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| - | + | == Getting started == | |
| - | + | If you use csh or tcsh (echo $SHELL to see which one - unless you asked for a change, it should be bash), add '<tt>source /usr/peyton/bin/idl_setup</tt>'to your .cshrc file. If you use bash or ksh, put '<tt>. /usr/peyton/bin/idl_setup.ksh</tt>' in your .bashrc or .profile. Then run idl (/usr/peyton/bin/idl) to start. | |
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| + | == Color problems == | ||
| + | Sometimes the colors in IDL can seem all wrong. One workaround found on a web page suggests setting the image decomposition to 0 with '<tt>device,decomposed=0</tt>'. This has to be set in IDL before any windows are opened. The need for this comes about because IDL only works properly with 8-bit color. Obviously, with our new fangled modern video cards, no-one uses 8-bit anymore, hence the need to force the X-window to work as 8-bit. | ||
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| + | There is also a problem for IDL 5.5 running on linuxes with pixmap depth set to 24. The use of TVSCL or TV loads the wrong color map and gives a streaky appearance to the graphics. You can prevent this by adding the lines '<tt>WINDOW, /PIXMAP & WDELETE</tt>' and '<tt>DEVICE, BYPASS_TRANSLATION=0</tt>' to your .idl_startup file. If one is trying to read an image from the graphics window using TVRD, this workaround fails - one has to run X in depth 8 or 16. This problem is because IDL still cannot handle TrueColor in 24bit depth, though it can now handle it in 8 and 16 bits. | ||
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| + | [[Category:Software]] | ||
Revision as of 15:55, 15 May 2007
IDL is a data visualization & analysis program used by many in the department.
Getting started
If you use csh or tcsh (echo $SHELL to see which one - unless you asked for a change, it should be bash), add 'source /usr/peyton/bin/idl_setup'to your .cshrc file. If you use bash or ksh, put '. /usr/peyton/bin/idl_setup.ksh' in your .bashrc or .profile. Then run idl (/usr/peyton/bin/idl) to start.
Color problems
Sometimes the colors in IDL can seem all wrong. One workaround found on a web page suggests setting the image decomposition to 0 with 'device,decomposed=0'. This has to be set in IDL before any windows are opened. The need for this comes about because IDL only works properly with 8-bit color. Obviously, with our new fangled modern video cards, no-one uses 8-bit anymore, hence the need to force the X-window to work as 8-bit.
There is also a problem for IDL 5.5 running on linuxes with pixmap depth set to 24. The use of TVSCL or TV loads the wrong color map and gives a streaky appearance to the graphics. You can prevent this by adding the lines 'WINDOW, /PIXMAP & WDELETE' and 'DEVICE, BYPASS_TRANSLATION=0' to your .idl_startup file. If one is trying to read an image from the graphics window using TVRD, this workaround fails - one has to run X in depth 8 or 16. This problem is because IDL still cannot handle TrueColor in 24bit depth, though it can now handle it in 8 and 16 bits.
