Overlay polygon on geographic axes

I would like to overlay a patch (filled polygon) on a geographic axis created using geoaxes. Is there any way to do this in R2019b? I have only found functions for plotting lines and symbols (geoplot, geoscatter).

This would be similar to patchm in the mapping toolbox.

Answer 1

[Subhadeep Koley]

You can use the patch() function to achieve the same. Use the code below.

% Plot your Geo data here
latSeattle = 47.62;
lonSeattle = -122.33;
latAnchorage = 61.20;
lonAnchorage = -149.9;
gx = geoaxes;
geoplot(gx,latSeattle,lonSeattle);
geobasemap(gx,'landcover');
 
% Plot your Patch data here
ax2 = axes;
x = [0.25 0.6 0.6 0.25]; % Modify x coordinates of the polygon 
y = [0.25 0.25 0.4 0.4]; % Modify y coordinates of the polygon
patch(ax2, x, y,'red','FaceAlpha',.4); % Modify patch color and transparency 
axis([0 1 0 1]);

% Set ax2 visibility to 'off'
ax2.Visible = 'off'; 
ax2.XTick = []; 
ax2.YTick = []; 

[Caroline Nowlan]

Works perfectly. Thanks!

[Evan Bates]

Does not work with appdesigner.

[Kurt]

This may work, but the patch has its own axis, and is not bound to the geoaxes object gx. You can grab it and move it around, independent of the background. They just happen to share the same frame, is all. Is there a way to bind these two objects so the patch won't move?

Answer 2

[Mike D.]

What if you had (lat,lon) coordinates of the polygon you wanted to overlay? It looks like your x and y coordinates might be normalized coordinates?

[erik jensen]

I have same question .. what kind of coordintaes ae [0.25 0.6 0.6 0.25]?

[Mike D.]

Notice he is creating a new ax2 = axes overtop of the geoaxes, and then setting its limits to be axis([0 1 0 1]); So the coordinates are effectively normalized to the width and height (0 to 1).

This is more of a work-around by creating another axes overtop and making its axes labels invisible. Hopefully a future version of Matlab allows the geoaxes to create a patch on the geoaxes.

[Brad Onstott]

Mike D: Good call! MATLAB 2022b does allow for an overlay consisting of user-defined Lat/Long coordinates.

[Mike D.]

Brad, are you saying the patch command now allows color filled polygons on geoaxes, or maybe after creating a polyshape with geopolyshape?