www.gusucode.com > map 案例源码 matlab代码程序 > map/VisualizeProjectionDistortionsUsingIsolinesExample.m
%% Visualize Projection Distortions using Isolines % This example shows how to visualize map projection distortions using % isolines (contour lines). Since distortions are rather orderly and vary % continuously, they are well-suited for isolines. The |mdistort| function % can plot variations in angles, areas, maximum and minimum scale, and % scale along parallels and meridians, in units of percent deviation % (except for angles for which degrees are used). %% % Create a Hammer projection map axes in normal aspect and plot a % graticule and frame. figure axesm('MapProjection','hammer','Grid','on','Frame','on') %% % Load the coast data set and plot it as green patches. load coastlines patchm(coastlat,coastlon,'g') %% % Plot contours of minimum-to-maximum scale ratios, using |mdistort| . % Notice that the region of minimum distortion is centered around (0,0). mdistort('scaleratio') %% % Repeat this diagram with a Bonne projection in a new figure window. % Notice that the region of minimum distortion is centered around (30,0) % which is where the single standard parallel is. You can toggle the % isolines by typing |mdistort| or |mdistort off| . figure axesm('MapProjection','bonne','Grid','on','Frame','on') patchm(coastlat,coastlon,'g') mdistort('scaleratio')