IDL codes

http://www.astro.washington.edu/users/yoachim/code.php

guvciew

install guvcview
open a terminal type dmesg click enter
after it stops type lsusb click enter
try the cam in guvcview

Plot 3D in IDL

http://www.idlcoyote.com/tip_examples/plots3d.pro

http://idlastro.gsfc.nasa.gov/idl_html_help/PLOTS.html

ps2pdf with bounding box

To convert ps file to pdf using non-standard file size (default is A4) first read off the bounding box from the ps file :
%%BoundingBox: 0 0 1275 236

Then :
ps2pdf -dDEVICEWIDTHPOINTS=1275 -dDEVICEHEIGHTPOINTS=236 file.ps file.pdf


For ps files with offset or in general easier method:

ps2pdf file1.ps file2.pdf (give device width and height with added space if needed)
pdfcrop file2.pdf file3.pdf


For color images, default setting is to resort to lossy JPEG compression. To set to lossless compression for better images set options:
 -dAutoFilterColorImages=false  -dColorImageFilter=/FlateEncode

Expanded options list:

ps2pdf -sPAPERSIZE=a4  -dCompatibilityLevel=1.3  \
 -dEmbedAllFonts=true  -dSubsetFonts=true  -dMaxSubsetPct=100  \
 -dAutoFilterColorImages=false  -dColorImageFilter=/FlateEncode  \
 -dAutoFilterGrayImages=false  -dGrayImageFilter=/FlateEncode  \
 -dAutoFilterMonoImages=false  -dMonoImageFilter=/CCITTFaxEncode  \
 document.ps  document.pdf

The important thing for the image quality is AutoFilter...Images=false and ...ImageFilter=/FlateEncode. The first disables the automatic determination by Ghostscript of the "best" compression format, which tends to favour /DCTEncode, lossy JPEG encoding. The second set of options manually set the compression method to the lossless (de)flate encoding for colour and greyscale images and to CCITT encoding for monochrome images.

Source: https://www.volkerschatz.com/tex/hiqpdf.html

FFT

FFT in IDL vs Fortran

http://www.ssec.wisc.edu/~paulv/fft/fft_comparison.html

Misc find / ls / linux cmds

find path -type d -ls  : lists all directories in given path

Visit

Volume rendering :

Steps :

1. Open - > load variable
2. Add volume -> rho
3.  plotatts - > volume -> splatting
4. set Tranparency : plotatts -> 1D transfer function
The grey bar denotes colors that are plotted. Removing grey area means those colors WILL NOT be shown in the 3-d rendering
5. choose color scale. hot desaturated is good.
6. Raycasting (composting) 600 points look ok


Make 3D vector field stream lines:

First create a vector vtk file with 3 components. Use Write_vtk,qx,qy,qz IDl routine

> Load vecfield

> Pseudocolor-->operators-->IntegralCurve-->vecfield

Click on Integral Curve to open operator attributes. Adjust as per choice.
Common adjusts:
1. source type: circle
2. Choose circle radius etc
3. Integration direction: Both for up and downsteam both.
4. Tab: Appearance--> Data Value: absolute time for checking progress or speed for magnitude

Click on pseudocolor for plot attributes
1. --> Geometry --> Line type: Tubes