plotting lat, lon, altitude, variable

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

Answer 1

[Chad Greene]

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

Answer 2

[Sagar]

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);

[Chad Greene]

Interesting. I'm guessing your permuted_ext_mean variable has a lot of NaN values? Around line 74 of pcolor3 there's a slice line with the 'cubic' interpolation option chosen. There's a small chance that changing 'cubic' to 'linear' or 'nearest' will make it work. In the meantime I may tinker with an interpolationless solution.

[Chad Greene]

I've just updated the function with a 'direct' option, which will plot your data directly instead of interpolating between points.

[Sagar]

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

[Sagar]

Here is what I got with pcolor3, I am fully satisfied now. Thanks Chad.

Answer 3

[Chad Greene]

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

[Sagar]

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)

Answer 4

[Sagar]

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);

[Chad Greene]

Or similarly,

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