Why do the colors in the color bar of a "contourfm" plot get non-uniformly distributed over the updated range of color axis, when I update the color axis limits using "caxis"?

Execute the following commands to generate a contour map:

 

>> figure
>> axesm eckert4; framem; gridm; axis off; tightmap
>> load geoid
>> contourfm(geoid, geoidrefvec, -120:20:100, 'LineStyle', 'none');
>> coast = load('coast');
>> geoshow(coast.lat, coast.long, 'Color', 'black')
>> contourcbar

Now update the color axis limits to a wider range, [-300 300], by executing the following command

 

>> caxis([-300 300])

The colors on the color bar get non-uniformly distributed over the updated range of color axis.

How can these colors be distributed uniformly over the updated range of color axis?

Answer 1

[MathWorks Support Team]

The colors can be distributed uniformly on the color bar by specifying the wider range of the color axis limit within the "contourfm" command as follows:

 

>> contourfm(geoid, geoidrefvec, -300:20:300, 'LineStyle', 'none');

This will ensure a uniform distribution of colors on the color bar when the color axis limits are updated to [-300 300].

Now use "caxis" to change the color axis limits to [-300 300]. It will update both the color bar and the plot accordingly.

 

>> caxis([-300 300])

Also, if a wider range of colors is needed, an appropriate color map can be used, e.g., "jet" can be used by executing the following command:

 

contourcmap jet