MATLAB: Does the figure change to display the entire world when I set the map projection to ‘eqaazim’ in the Mapping Toolbox in MATLAB 7.7 (R2008b)

Mapping Toolbox

I am trying to display map axes of Western USA with the 'eqazzim' map projection as shown in the code below.
h=usamap([33 35],[-119 -116]);
setm(h,'mapprojection','eqaazim')
However, I observe that instead of displaying rectangular map axes of just the Western USA, the figure diplays the map of the entire world.

Best Answer

The result that we observe is expected and it is necessary to set additional parameters in addition to the projection type to further control the limits of the new map.
The initial map is in a Lambert Conformal Conic (LAMBERT) projection, which is parameterized very differently from an Equal Area Azimuthal (EQAAZIM). So although it is possible to keep the same origin (latitude = 0, longitude = -117.5), SETM replaces the frame limits (FLatLimit and FLonLimit) value with the EQAAZIM defaults. This is because the frame limits from the LAMBERT map would not be helpful.
Assuming that you intend to cover the same general area on the Earth but using Equal Area Azimuthal, then it is best to manually reset both the origin and frame limits as shown in the example below.
setm(gca,'Origin',[34 -117.5],'FLatLimit',[-Inf 2.5])
This sort of adjustment is more likely to be required if the map covers a small portion of the Earth than for a map with global or regional extent.
Related Question