MATLAB Answers

Making a Map Image from a Matrix

31 views (last 30 days)
John Ziggs
John Ziggs on 13 Mar 2021
Commented: Chad Greene on 14 Mar 2021
Hi all, I am trying to make a map based off data from a text documents containing daily surface air temperature. I attached 2 txt files as a sample. I am trying to create a map based off this.
This is my code:
inputdirTA = 'C:\Users\john\Desktop\TA2004daily'; %directory of folder containing data
S = dir(fullfile(inputdirTA,'*.txt'));
for k = 1:numel(S)
fnm = fullfile(inputdirTA,S(k).name);
vector = load(fnm);
mtx = reshape(vector,72,144);
if k == 1;
DataTA = [mtx];
DataTA = [DataTA mtx];
rv = [0.4 90 0];
geoshow(DataTA, rv, 'displaytype', 'texturemap');
C = load('coast');
plotm(, C.long, 'k');
title('Map of Surface Air Temperature');
I am getting this map:
But I am trying to get this kind of map:
I understand the concept of having to create 3 planes of the matrix, but I am having troubles understanding the syntax.
Any help or advice is greatly appreciated.

Accepted Answer

Chad Greene
Chad Greene on 13 Mar 2021
Edited: Chad Greene on 13 Mar 2021
With the Climate Data Toolbox you could do it like this:
T = flipud(reshape(load('TS20040101.txt'),[72 144])); % loads, reshapes, and orients the data correctly
[lat,lon] = cdtgrid(2.5); % creates a 2.5 degree global grid
pcolor(lon,lat,T) % plots the grid
shading interp
cmocean thermal % sets the colormap
xlabel longitude
ylabel latitude
You could even take it one step further and interpolate to a high-resolution grid, then plot with hillshaded topography:
% Create a 0.1 degree grid:
[lati,loni] = cdtgrid(0.1);
% Interpolate the temperature data to the high-res grid:
Ti = interp2(lon,lat,T,loni,lati);
% Get elevation data on the high res grid:
Zi = topo_interp(lati,loni);
% Set ocean elevations to zero:
Zi(Zi<0) = 0;
shading interp
axis tight equal
cmocean thermal
shadem(-10) % applies hillshade
Chad Greene
Chad Greene on 14 Mar 2021
Thanks, Mark! That means a lot coming from you!

Sign in to comment.

More Answers (0)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by