www.gusucode.com > map 案例源码 matlab代码程序 > map/DrapeGeoidHeightsOverTopographyExample.m
%% Drape Geoid Heights Over Topography % This example shows the figure of the Earth (the geoid data set) draped on % topographic relief (the topo data set). The geoid data is shown as an % attribute (using a color scale) rather than being depicted as a 3-D % surface itself. The two data sets are both 1-by-1-degree meshes sharing a % common origin. %% % Load the topographic ( |topo| ) and geoid regular data grids. load topo load geoid %% % Create a map axes using a Gall stereographic cylindrical projection (a % perspective projection). Use |meshm| to plot a colored display of the % geoid's variations, but specify |topo| as the final argument, to give % each |geoid| grid cell the height (_z_ value) of the corresponding |topo| % grid cell. Low geoid heights are shown as blue, high ones as red. axesm gstereo; meshm(geoid,geoidrefvec,size(geoid),topo) %% % For reference, plot the world coastlines in black, raise their elevation % to 1000 meters (high enough to clear the surface in their vicinity), and % expand the map to fill the frame. load coastlines plotm(coastlat,coastlon,'k') zdatam(handlem('allline'),1000) tightmap %% % Due to the vertical view and lack of lighting, the topographic relief is % not visible, but it is part of the figure's surface data. Bring it out by % exaggerating relief greatly, and then setting a view from the % south-southeast. daspectm('m',200); tightmap view(20,35) %% % Remove the bounding box, shine a light on the surface (using the default % position, offset to the right of the viewpoint), and render again with % Gouraud shading. ax = gca; ax.Box = 'off'; camlight; lighting Gouraud %% % Finally, set the perspective to converge slightly (the default % perspective is orthographic). Notice that the geoid mirrors the % topography of the major mountain chains such as the Andes, the Himalayas, % and the Mid-Atlantic Ridge. You can also see that large areas of high or % low geoid heights are not simply a result of topography. ax.Projection = 'perspective';