michaelgalloy.com

I found this article fascinating. Basically, there are differences in color perception due to culture/language. Do I have to take into account the native language of the viewers of a visualization when choosing colors for it? Two colors that are easily distinguishable for me, may not be for someone else from a different culture (not to mention issues with color blindness).

Link via WeLoveDatavis.

ITT VIS announced the 3rd Annual IDL User Group Meeting scheduled for February 24 (with hands-on seminars on February 23) in Boulder, CO at LASP. Topics include:

1. Atmospheric and Cryospheric Analyses
2. Climate Modeling
3. General Physics and Mathematics
4. Graphics and Visualization
5. GPU Processing
6. Cluster Processing
7. Graphics Enhancements with IDL
8. New Functionality in the IDL Core Language

The Tuesday hands-on seminar schedule is:

 9:00–11:30 Introduction to Scientific Programming with IDL
11:30– 1:00 Lunch Provided by ITT
 1:00– 3:30 IDL 8.0 Tech Preview
 3:45- 5:00 IDL Roundtable

I will be there for both days and Tech-X should be talking about GPULib.

Register soon, as space is limited!

Here are the most popular posts of 2009:

1. Apple Keynote templates for posters
2. Overview of flow visualization in IDL
3. Path management
4. IDL roadmap
5. Google Earth user function for ENVI
6. 1RM: Mac OS X Dashboard widget
7. Processing with Javascript
8. Regular expressions
9. Response to Why IDL Sucks
10. A simple 3D object graphics example

Only one of these was actually posted in 2009, 4 in 2006, 4 in 2008, and 1 “page”. So maybe this is like Star Trek movies, where only the even numbered years are good? Good thing we are in 2010 then!

The first goal for my rIDL project was to completely emulate of all of command line IDL’s functionality. Once that is implemented, then extra cool stuff can be added. I’m getting close this goal (of course, I couldn’t help myself and there is some extra cool stuff in there already).

I have addressed two items where rIDL was not up to IDL’s standards:

1. events were not handled properly when running widget programs
2. commands were not saved between sessions

I still need to allow setting preferences with a command line switch when starting IDL as in:

$ idl -IDL_QUIET 1

There are plenty of small things that are not quite exactly the same, e.g., rIDL does not check the IDL_RBUF_PERSIST preference yet, is just assumes that you want the command history to persist between sessions. It will take some time to sort all these out (and even to discover what they are).

The code is not ready for a formal release yet. But those interested in poking around can get the code with Subversion:

svn co http://svn.idldev.com/ridl/trunk

It should build on Mac OS X (but you have to build GNU Readline first), but you are on your own on other platforms. If you have questions, comments, suggestions, etc. let me know!

Proceedings of the 8th Python in Science Conference are now available. I would love to have something like this for IDL.

Link via Gaël Varoquaux.

Here is a catalog of the color tables from cpt-city that can be read into IDL with VIS_CPT2CT that I wrote about previously.

Homebrew is a packaging system for Mac OS X, similar to Fink or MacPorts. I have used both Fink and MacPorts, but do not like having an entirely separate system of installs. Homebrew can install in /usr/local like a normal, well-behaved installation.

I installed Homebrew in /usr/local with the recommended commands, except I used sudo instead of changing the owner of /usr/local as shown in the Homebrew docs:

$ cd /usr/local
$ sudo git init
$ sudo git remote add origin git://github.com/mxcl/homebrew.git
$ sudo git pull origin master

Then installing a new formula is as easy as:

$ brew search svn
svn
$ sudo brew install svn

People can contribute new formulas; they are Ruby scripts that do the steps required to build the package.

I haven’t used this a lot yet, but this looks like a good solution to the problem. Any one using this yet?

ITT VIS hosted a users group meeting at AGU to announce IDL 8.0. With over 40 IDL users in attendance, Bill Okuko, IDL Product Manager, gave an introduction to the major features while Chris Torrence, IDL Development Manager, provided the details.

The main goals of this release are to “modernize and simplify” IDL. The features discussed fell into four categories: Workbench, language, graphics, and a new graphics API.

Continue reading “AGU IDL Users Group Meeting.”

xkcd has another great science-related comic today.

Looking forward to the arrival of xkcd: volume 0 and mousepad for (a slightly late) Christmas!

The cpt-city website has a large collection of over 4,000 color tables (download of over 4,000 color tables). Unfortunately for us (i.e., me), they are all in the .cpt format used in GMT. Here’s a routine to read a .cpt file and return it as a 256 by 3 color table array:

IDL> rgb = vis_cpt2ct('gmt/GMT_copper.cpt')
IDL> help, rgb
RGB             BYTE      = Array[256, 3]        
IDL> tvlct, rgb

Now I need a catalog that I can scan through to find a color table.