MATLAB Answers

Plot polygons defined by the specific points on map

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AJ
AJ on 8 Jul 2021
Commented: millercommamatt on 12 Jul 2021
Hi, I'm using mapping toolbox to display some geographical data.
After plotting some lines using 'geoplot'; 'geoshow' or 'patchm' are not working.
How do I plot polygons in geographic coordinates?
I've tried this:
lats= [30 32 31; 29 30 31];
lons = [-102 -103 -104; -100 -103 -101];
geoplot([30 32], [-102 -104])
for i = size(lats,1)
geoshow(lats(i,:),lons(i,:),'DisplayType','polygon');
end
And this is not what I want;
https://mathworks.com/matlabcentral/answers/487959-overlay-polygon-on-geographic-axes
Thank you for your help.

Answers (1)

millercommamatt
millercommamatt on 8 Jul 2021
There are many ways to do this, but this works.
lats= [30 32 31; 29 30 31];
lons = [-102 -103 -104; -100 -103 -101];
[numrows, ~] = size(lats);
usamap([28 33], [-105 -99]); % create map axis
for ii=1:numrows
patchesm(lats(ii,:),lons(ii,:),'b'); % blue polygons
end
  2 Comments
millercommamatt
millercommamatt on 12 Jul 2021
I think understand what you're trying to do now. You want to use geo plot types and non-geo plot types together.
The example that you said you didn't want, combined a GeographicAxes with a second hidden axis. I don't think you can combine use of the geo plot type and non-geo plot types any other way. A further complication is that the rulers of a GeographicAxes aren't linear. I don't know how you would get point in one axis to align with the other. Until Mathworks provide better cross compatability for working with GeographicAxes, I'd stick with map axes.

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