How do I add an image on a map?

I have a map on a figure. For example:

worldmap([27 28.5],[127.5 129])

How do I add an image at the range:

lat: 28~28.25

lon: 128~128.25

Answer 1

[MathWorks Support Team]

First, you need the projection method.

Then you can use the projection method information to convert the (lat,lon) coordinate on the map to (x,y) coordinate on the figure.

Lastly, you can use the (x,y) coordinate information to add the image on the figure.

Please see the follow sample code:

%%create a map
worldmap([27 28.5],[127.5 129])

% get the default projection method
mstruct=gcm
% the map projection method is 'eqdconic'
% check these websites for the project method:
% https://www.mathworks.com/help/map/summary-and-guide-to-projections.html
% https://www.mathworks.com/help/map/eqdconic.html

% By using this projection information, you can convert (lat,lon) to (x,y)
% on the figure
myLat = 28;
myLon = 128;
[x, y] = mfwdtran(mstruct,myLat,myLon);
scatter(x,y,'ro')
hold on

%%image
eLat = 28;
eLong = 128;
sizeDeg = 0.25;

img = imread('peppers.png');
latlim=[eLat eLat+sizeDeg];
lonlim=[eLong eLong+sizeDeg];

% show the frame of the image, you can skip this step
[xlim, ylim] = mfwdtran(mstruct,latlim,lonlim);
plot([xlim(1) xlim(2) xlim(2) xlim(1) xlim(1)],[ylim(1) ylim(1) ylim(2) ylim(2) ylim(1)],'y-')

% show the image
R = maprefcells(xlim,ylim,size(img(:,:,1)));
mapshow(img,R)