Archive for April, 2006

Wednesday, April 26th, 2006

Why I switched to object graphics (most of the time)

I’m finding myself using object graphics over direct graphics more and more in my projects. My rule used to be to use direct graphics unless there was a compelling reason to use object graphics. This rule has now reversed itself, making object graphics the new default for me. Here are the reasons which have lead […]

4 Comments » - Posted in IDL,Object graphics by

Monday, April 24th, 2006

Collection package: MGArrayList

One area that is sorely missing in IDL’s library is more flexible collections. Sure, arrays are extremely powerful in IDL and we should try to use them whenever possible. But sometimes arrays are just not the right tool for the job. There are two main cases which arrays don’t handle well: Arrays can’t have zero […]

No Comments » - Posted in IDL,Objects by

Friday, April 21st, 2006

Dichotomous sparklines

Following up on the sparklines implementation, I have a dichotomous sparkline implementation now. These are the same type of simple, “word-size graphics” except they visualize something that is either on or off (with an optional neutral value). For example, my favorite baseball team the Chicago Cubs have started this season 9-5. For completeness, here are […]

No Comments » - Posted in IDL,Visualization by

Wednesday, April 19th, 2006

Sparklines implementation

Sparklines are “simple, word-size graphics” intended to be be incorporated into a paragraph or table of words as equals. For example, the high was 55 degrees in Boulder today. But, this is put in context with a simple plot of the last 28 days highs 55. Now obviously, some of the features of a full-sized […]

2 Comments » - Posted in IDL,Object graphics,Visualization by

Monday, April 17th, 2006

Update to Google Maps lookup for ENVI

I upgraded to Version 2 of the Google Maps API. The benefits of Version 2 of the API that are applicable for the ENVI lookup user routine are: The Overview map control displays a collapsible overview map in the lower-right corner of the browser window. The Javascript is half the size, so it should be […]

2 Comments » - Posted in ENVI by

Saturday, April 15th, 2006

IDLgrImage tiling in IDL 6.2

IDL 6.2 added several new capabilities to the IDLgrImage class in the object graphics system. One of them is the ability to support large images using tiling. (Another is significantly faster rendering time in typical cases.) The new tiling features allow portions of the image to be read from a data source as needed. For […]

3 Comments » - Posted in IDL,Object graphics,Widgets by

Wednesday, April 12th, 2006

Newest Edward Tufte book available for pre-order

Edward Tufte’s latest book, Beautiful Evidence can be pre-ordered from or directly from Tufte’s site. Not sure if it means anything, but Amazon says it will be available July 30 and Tufte’s site says May. Mine is on order from his website; I will be sure to post my thoughts once I get my […]

7 Comments » - Posted in Books,Visualization by

Wednesday, April 5th, 2006

Google Maps lookup for ENVI

This ENVI user function will add a “Find location using Google Maps” in the Tools menu of the display window for any image with map information. Selecting it will bring up the location of the image with Google Maps in your default browser. Also included is a helper routine called MG_OPEN_URL which is useful in […]

4 Comments » - Posted in ENVI by