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Sagar
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plotting lat, lon, altitude, variable

Asked by Sagar
on 9 Mar 2015
Latest activity Commented on by Chad Greene
on 16 Mar 2015
I have 3 vectors of latitude, longitude, and elevation respectively. I also have a corresponding 3d matrix of size latitude*longitude*elevation which contains some data (Temperature). I want to display the Temperature data in 3d space. What is the best way to do this? Note: I don't want to use trisurf because it requires reshaping the matrix into 3 separate vectors, with which I found difficulty in tracking the data points.
Many thanks.
-Sagar

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4 Answers

Answer by Chad Greene
on 11 Mar 2015
 Accepted Answer

You can try pcolor3, although it does not work for Matlab 2014b.
% Some data:
[lon,lat,z] = meshgrid(-180:3:180,-90:2:90,0:50:1000);
T = 20 - .1*abs(lat) - .01*z + sind(lon);
% Plot dataset:
pcolor3(lon,lat,z,T);
% Add labels:
xlabel('longitude')
ylabel('latitude')
zlabel('elevation (m)')
title('temperature or something')
axis tight

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Answer by Sagar
on 12 Mar 2015
Edited by Sagar
on 12 Mar 2015

Hi Chad, thanks a lot. I tried pcolor3 that you suggested, but with no success.
Please let me know if I did something wrong. I did:
pcolor3(X, Y, Z, permuted_ext_mean); % X, Y, Z and permuted_ext_mean all have 72*85*208 size.
I got following error in Matlab 2013b. Also, it would be great if you could put a colorbar in the output image. Error using interp3/stripnanwrapper (line 204) Insufficient finite values to interpolate.
The closest one I found for my purpose is isosurface, although I am not completely satisfied: surf2 = isosurface(X, Y, Z, permuted_ext_mean, isovalue);

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I've just updated the function with a 'direct' option, which will plot your data directly instead of interpolating between points.
Yes, a lot of NaN values. Just tried the updated one, works well now. It is a bit slow though compared to isosurface, may be it is normal for pcolor.
-Sagar
Here is what I got with pcolor3, I am fully satisfied now. Thanks Chad.

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Answer by Chad Greene
on 14 Mar 2015

Great! You may also want to add a coast line for context as shown here.

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Hi Chad, that is a great suggestion and I am trying to do that as below. Is there a way to specify the range of latitude and longitude, say, in my case, 0 to 40N, -20 to 70E (so the length of the two vectors would be unequal). c = load('coast.mat'); plot(c.long,c.lat) view (3)

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Answer by Sagar
on 15 Mar 2015

Never mind! I was able to plot as I wanted with a small tweak. This is what I did:
load ('coast.mat');
long (long < -20 | long > 70 = NaN;
lat (lat < 0.00 | lat > 40.00) = NaN;
plot (lat, long);

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Or similarly,
in = ingeoquad(lat,long,[0 40],[-20 70]);
long(~in) = NaN;
lat(~in) = NaN;

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