A simple function to plot a basemap image in MATLAB. Requires MATLAB's Mapping Toolbox.

This function uses the Mapping Toolbox function readBasemapImage to download a satellite or street map image, then reprojects the image a specified projection, using the extents of any current map that might be open.

Syntax

plot_basemap(authority,code)
plot_basemap(authority,code,'basemap',basemap) 
[h,Im,x,y,attrib] = plot_basemap(...) 

Description

plot_basemap(authority,code) fills the current extents of a map with a satellite image basemap. The current map must already be open and in the projection defined by authority,code. The authority can be 'EPSG' or 'ESRI' and the code is numeric.

plot_basemap(authority,code,basemap) specifies the type of basemap called by readBasemapImage. Default is "satellite", and can be changed to "streets", "streets-light", or "streets-dark".

[h,Im,x,y,attrib] = plot_basemap(...) returns the handle h of the plotted image, and image data Im, its coordinates, and attrib given by readBasemapImage.

But why?

I frequently work in projections that are not directly supported by MATLAB's readBasemapImage function. To work in polar stereographic, for example, we need to transform the native output of readBasemapImage into EPSG:3413, and this function does all the work.

Example

In the example below, we open a new figure, set the axis limits in north polar stereographic meters, then plot a basemap.

% Open a figure:
figure
 
% Set map axis limits around Jakobshavn Glacier:
axis([-196980    -171290   -2285131   -2256724])
 
% Download and plot a basemap:
plot_basemap('EPSG',3413)

Author Info

Chad Greene of NASA/Jet Propulsion Laboratory, July 2024.