How to generate a geographical heat map? (worldwide, country-level granularity)

I want to create a geographical heat map like the following in MATLAB:

Each color is based on a list of country with a percentage associated to each of them:

Country with Codes: % of Hits

 - United States (US): 36.29% 
 - India (IN): 18.24% 
 - United Kingdom (GB): 12.93% 
 - Spain(ES): 8.22% 
 - Australia (AU): 3.32% 
 - Canada (CA): 3.05%
 - Germany (DE): 2.49% 
 - Netherlands (NL): 1.66% 
 - Israel (IL): 1.39% 
 - China (CN): 0.83%

How can I do it in MATLAB?

I looked at http://mathworks.com/products/mapping and Googled around but I didn't find any easy way to do it. Such kind of maps are commonly used (e.g. straightforward to do with the Google Chart API) so I'm hoping someone here shares his/her experience.

Thanks,

Franck

[1]: http://i.stack.imgur.com/64DJY.png

[Brahim HAMADICHAREF]

I am curious ... have you ever managed to do the same with the Mapping toolbox ? I also use Google maps API, but an only MATLAB solution would prefer !

Brahim

[Franck Dernoncourt]

Never :/ I also posted the question on Stack Exchange

Answer 1

[Antti]

This can be quite easily done with the Mapping toolbox. Here's an example:

% read a shapefile with some regions in it
S = shaperead('usastatelo.shp');
numRegions = length(S);

% show the map
mapshow(S)

% get the current colormap
cmap = colormap;
numColors = size(cmap,1);

% create some random data [1 numRegions], each data point is associated with a region
data = randi(numColors,1,numRegions);

% set the colors of the regions using the 'FaceColor' -property
for i = 1:length(S)
    % FaceColor is now a color from the current colormap, determined by
    % it's data value
    mapshow(S(i),'FaceColor',cmap(data(i),:))
end

This gives me the map figure in the attachment.

[Rui Li (AIRicky)]

Thank you. I have a question on the answer. If my data is not integer, and range from 0.1 to 50.9, how can I specify the color for each region and add corresponding colorbar?

[MikCh]

Nice approach!

What if the data variable include both positive and negative values?

How do we need to modify mapshow(S(i),'FaceColor',cmap(data(i),:)) in the loop so as to accept negative values?