Doug’s MATLAB Video Tutorials

November 15th, 2007

• The colormaps that we are developing from a journal article
• The colormap applied to a MATLAB figure
• How to call the code to make the colormap
• Explaining the structure of a colormap in MATLAB
• Exploring colormaps in the colormap editor
• Plotting a colormap to understand its structure
• Creating the colormap creating subfunction
• Testing the subfunction

• We review the colormaps that are to be made.
• Show the four expected calling syntaxes for the function
• Show how to use VARARGIN to make deal with different numbers of input arguments
• Show error catching
• Show different branches of code to be followed based on inputs
• Developing an algorithm with cell mode to test an algorithm
• Testing
• Documentation

Find the files here. PodCast here This code was written live, so mistakes were made along the way. This gives you a realistic view of how a MATLAB expert deals with the inevitable errors that occur while programming. The file that got created is useful on its own, so I have posted it here Other videos have been gathered here: http://blogs.mathworks.com/pick/category/video/ Practical example videos have been gathered here: http://blogs.mathworks.com/pick/category/practical-example

14:57 UTC | Posted in Format: PodCast, Format: Video, Topic: Practical example | Permalink |

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5 Responses to “Practical example: Algorithm development for making colormaps”

1. Dan Pace replied on November 19th, 2007 at 09:24 UTC :
   

   Hi Doug - thanks for the helpful video. I have a question. Is it possible to display two surface plots, with different colormaps, on the same axes? Thanks - Dan

2. Doug replied on November 19th, 2007 at 10:13 UTC :
   

   Dan,

   The colormap is a property of the Figure, so all axes in a figure share it.

   Doug

3. Amir replied on November 20th, 2007 at 01:22 UTC :
   

   Dan,
   Here is the solution -
   http://www.mathworks.com/support/tech-notes/1200/1215.html
   Amir

4. Andy replied on December 30th, 2007 at 22:59 UTC :
   

   Hi Doug - Thank you for creating the very useful makeColorMap. My goal was to integrate this function into my plots that use contourcmap.m. However, I kept getting an error, ‘cmap string must contain a colormap function name’ since contourcmap only allows built in Matlab color maps. My way around this was to comment out lines 64-68 of contourcmap. Do you recommend this solution, and if not, what other methods could I try? Thanks!

5. Doug replied on January 2nd, 2008 at 11:06 UTC :
   

   Andy,

   What was the commands you were using? I just tried the example in CONTOURCMAP only I made a throw-away function JETT that just calls JET. This worked fine. Please send or post the code you used and we can figure this out.

   I suspect that my colormap function expects different inputs than CONTOURCMAP gives so things are not working. You will probably want to make a wrapper around my function that takes just a single number input (like JET and other colormap functions do) so that when CONTOURCMAP calls it it will behave like the others.

   Doug

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