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Use Geographic and Nongeographic Objects in Map Axes

This example shows how to use geographic and nongeographic objects in a map axes. The example illustrates the difference between using MATLAB functions, such as plot and grid, and their Mapping Toolbox counterparts, plotm and gridm .

Make a Miller map axes with a latitude and longitude grid. These functions create a map axes object, a map frame enclosing the region of interest, and geographic grid lines. The x-y axes, which are normally hidden, are displayed, and the axes x-y grid is turned off. The gridm function constructs lines to illustrate the latitude-longitude grid, unlike the MATLAB grid function, which draws an x-y grid for the underlying projected map coordinates. Depending on the type of projection, a latitude-longitude grid (or graticule) can contain curves while a MATLAB grid never does.

axesm miller; 
framem on;
gridm on;
mlabel on;
plabel on;
showaxes;
grid off;

Figure contains an axes. The axes contains 29 objects of type patch, line, text.

Place a standard MATLAB text object and a mapped text object, using the two separate coordinate systems. In the figure, a standard text object is placed at x=-2 and y=-1, while the mapped text object is placed at (70 degrees N, 150 degrees W) in the Miller projection.

text(-2,-1,'Standard text object at x = -2, y = -1')
textm(70,-150,'Mapped text object at lat = 70, lon = -150')

Figure contains an axes. The axes contains 31 objects of type patch, line, text.

Change the projection to sinusoidal. The standard text object remains at the same Cartesian position, which alters its latitude-longitude position. The mapped text object remains at the same geographic location, so its x-y position is altered. Also, the frame and grid lines reflect the new map projection. Similarly, vector and raster (matrix) data can be displayed using either mapping functions ( plotm ) or standard functions ( plot ).

setm(gca,'MapProjection','sinusoid')
showaxes; 
grid off; 
mlabel off

Figure contains an axes. The axes contains 18 objects of type patch, line, text.