You can use the mapping toolbox in MATLAB. I think the geoshow and save function may help (for display and saving). Refer to this code for some more understanding.
%setting up a figure with a Mercator projection for the map
figure
ax = axesm('MapProjection', 'mercator');
set(ax, 'Units', 'normalized', 'Position', [0 0 1 1]);
%set a pin given by user
[lat, lon] = inputm(1);
%display the pin
geoshow(lat, lon, 'Marker', 'o', 'Color', 'red', 'MarkerSize', 10);
%save the pin
save('pin_coordinates.mat', 'lat', 'lon');
%end of code
Hope this helps.
