MATLAB: Mapping, colormap, eigenvector

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Can anyone help me!!!

I want to plot countries including their borders in Europe and then set the color of each country according to a number. Currently I am able to generate a map consisting of about 50 country shape files. Now, I want to change the Facecolor of each shape file according to the value of an eigenvector.

My problem is, how to generate or calculate a colormap, so each number eigenvector correspond to a color (like the colormap jet). Large values would correspond to a darker red, small values to a darker blue etc… How can I do this ?

Best Answer

yes, butt how can I calculate a new colormap??

Related Solutions

MATLAB: Problem displaying 12 bit colormap, bug

Hi,

I'm not sure, if I understand correctly, but have you tried to display the image as an indexed image? Your 12 bit images, are they indexed? I.e., does your image has one channel (only) with values between 0 and 2047? In this case

imshow(snapshot, handles.myColourmap)

or, I'm not sure, maybe

imshow(snapshot+1, handles.myColourmap)

should work ...?

Titus

MATLAB: Mapping Toolbox: Eigenvector specifies Color of shape file

The easiest way to do this with complex polygons (multi-face polygons or polygons with holes, as is often the case with borders) in a mapping axis is to use the admittedly very unintuitive makesymbolspec function combined with mapshow or geoshow. The makesymbolspec function allows you to build a colormap with specified limits, and color the plotted polygons based on an attribute in the shapefile. (You can easily add additional attributes to the geostruct object if your eigenvalues are calculated independently rather than stored in the shapefile):

Usa = shaperead('usastatehi.shp', 'usegeocoords', true);
colorrange = makesymbolspec('Polygon', {'LabelLat', [20 65], 'facecolor', jet(64)});
worldmap('usa');
geoshow(Usa, 'SymbolSpec', colorrange);

Note that this sets each polygon face color to an rgb triplet, and this value is not actually linked to the mapping axis's colormap. So if you want to add a colorbar, you need to sync that to your spec:

set(gca, 'clim', [20 65]);
colormap(jet(64));
colorbar;

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Related Solutions

MATLAB: Problem displaying 12 bit colormap, bug

MATLAB: Mapping Toolbox: Eigenvector specifies Color of shape file

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