en Copyright 1997-2009, David W. Fanning david@dfanning.com (David Fanning) Mon, 08 Feb 2010 05:48:28 GMT david@dfanning.com (David Fanning) http://www.dfanning.com/index.html IDL Programming Tips and Examples http://www.dfanning.com/images/coyote_tips.jpg http://www.dfanning.com/index.html http://www.dfanning.com/code_tips/uniquename.html Creating a unique file name in IDL is sometimes harder than it looks. A new IDL program, TimeStamp, makes it easy to create file names that are guaranteed to be unique, even if they are created in a fast IDL loop. This article explores some of the features of the TimeStamp program and how they can be used to produce unique file and variable names. article 438 at dfanning.com Mon, 08 Feb 2010 05:48:28 GMT http://www.dfanning.com/programs/timestamp.pro Creates a time stamp string, with or without random numbers in the string, in 10 different formats. You can specify local or UTM time, and you can specify the format be in a form that can be used as a valid IDL variable name. The random numbers create a system variable using the RandomNumberGenerator object to guarantee they are random every time the TimeStamp function is called. article 437 at dfanning.com Mon, 08 Feb 2010 03:50:32 GMT http://www.dfanning.com/programs/randomnumbergenerator__define.pro Added a new GetRandomDigits method to the random number generator object. This method can generate a random sequence of numbers of any specified length. Normally, the numbers are returned as a string of digits, but by setting the BYTES keyword, the digits can be returned as a byte array. article 436 at dfanning.com Mon, 08 Feb 2010 03:50:32 GMT http://www.dfanning.com/programs/errorlogger__define.pro Modified the way default file names are created. I was having problems creating unique file names when several error loggers were created in a loop. I now take advantage of the TimeStamp program from the Coyote Library, which guarantees I can generate a truly random sequence of numbers for the file name. article 435 at dfanning.com Mon, 08 Feb 2010 03:50:32 GMT http://www.dfanning.com/programs/ncdf_data__define.pro Added a new keyword, NO_NEW_FILE, which suppresses the "Open New File" button on the Browse method interface. Also made the default browser window larger to accomodate longer variable names. article 434 at dfanning.com Mon, 08 Feb 2010 03:50:32 GMT http://www.dfanning.com/programs/ncdf_browser.pro Added four new keywords to this program. The NO_NEW_FILE keyword suppresses the "Open New File" button on the GUI interface. The TITLE keyword allows you to specify a title for the GUI interface. And the XOFFSET and YOFFSET keywords allow you to position the GUI interface on the display. article 433 at dfanning.com Mon, 08 Feb 2010 03:50:32 GMT http://www.dfanning.com/reading/coyote_reading.html Coyote's selections for January. Travel is on his mind this month. Here you find tales of two long hikes. One from Seattle to the tip of the Aleutian Islands by Erin McKittrick and her husband, Hig. The other from Mexico to Canada along the Continental Divide Trail by Karen Berger and her husband, Dan. Also, you will find Peter Hessler's account of the two years he spent teaching in Fuling, China. Finally, we look for answers to America's financial collapse in far-off Iceland. article 431 at dfanning.com Mon, 01 Feb 2010 03:43:49 GMT http://www.dfanning.com/programs/greek.pro This new IDL program makes it much easier to use Greek symbols in your plot annotations. The entire 24 characters in the Greek alphabet are supported in both lowercase and uppercase versions. Now it is easy to write code that works both in your graphics window and in your PostScript file. article 425 at dfanning.com Sun, 10 Jan 2010 00:14:03 GMT http://www.dfanning.com/ps_tips/greeksym.html Using Greek symbols in IDL plot annotations in a device-independent way (on your display and in a PostScript file, for example) is more difficult than it should be. The IsoLatin codes you have to use are different, the font families you have to use are different, the charts you need to figure it all out are unusually difficult to find in the IDL on-line documentation. This article explains what you need to know and points you to a new Coyote program that can make it easier to use Greek letters in plot annotations. article 424 at dfanning.com Sun, 10 Jan 2010 00:14:03 GMT http://www.dfanning.com/misc_tips/noxobjview.html A "silent" object that doesn't leave any trace of its existence in the IDL console can play absolute havoc with your mind if you are trying to make an IDL save file with XObjView that will run on the IDL Virtual Machine. The offending object, IDLexModelManip, is outted here. article 423 at dfanning.com Fri, 08 Jan 2010 15:36:26 GMT http://www.dfanning.com/code_tips/gridtps.html I have grave misgivings about teaching people how to replace missing data with "corrected" data, and yet I have been around the block enough to know it is often done. And, occasionally, for good reasons. Here is one method, using thin plate splines, to correct a 2D data set. Please use good judgement in reading this article. article 419 at dfanning.com Tue, 29 Dec 2009 19:27:19 GMT http://www.dfanning.com/map_tips/missinggrid.html I noticed recently that portions of my map grid lines, drawn with Map_Grid, were missing. I tracked the problem down to a Map_Proj_Forward call in the Map_Grid code. Map_Proj_Forward is simply returning incorrect results when the function is called with the PolyLines keyword. This article explains what is happening and how to fix Map_Grid so that grid lines are drawn properly on your maps. article 408 at dfanning.com Thu, 17 Dec 2009 04:11:18 GMT http://www.dfanning.com/documents/fanning_consulting.html Need help writing an IDL application? Like to consult an IDL expert? Quality IDL programming guaranteed. Currently accepting new IDL programming and consulting opportunities. Pressure of college tuition bills guarantees proprietor will not be offended by small projects, tight deadlines, or chinzy budgets! Call today for quality IDL programming: 970-221-0438. article 046 at dfanning.com Wed, 02 Apr 2008 03:42:50 GMT http://www.dfanning.com/adventures/index.html Want to know more about Coyote? Here are stories and essays of recent adventures. article 008 at dfanning.com Wed, 02 Apr 2008 03:42:50 GMT