Contour map to show ocean depth

Hello,

How can I construct a contour map as follows that shows the Ocean depths at a particular location, using Longitude, Latitude and Depth data. (Attached sample xlsx file)

I've been struggling to get something at least slightly similar and I have posted a few posts before this. I'm still learning MATLAB and this has been a dead end for me for some time now. So, literally ANY suggestion, recommendation or help is appreciated.

Now, Do I need more data? Or do I have to have a specific toolbox?

To clarify, I don't mind having different colors or a color bar than the one I have posted. My concern is getting the contour map generated as shown on the post.

Basically, the data refers to Lat, Lon and Depth/Altitude. I am interested in generatnig a contour map that shows different depths/altitudes based on that data set.

I'll add all my previous posts and reference here, to know what my intensions are.

https://www.mathworks.com/matlabcentral/answers/514760-create-contour-map-from-latitude-longitude-and-depth-from-csv-file

https://www.mathworks.com/matlabcentral/answers/519492-contour-plot-with-filled-colors-for-x-y-z-data

https://www.mathworks.com/matlabcentral/answers/519286-plot-bathymetry-data-on-google-earth-using-matlab

Thank you in advance!

Answer 1

[darova]

Use griddata

% lat, long, depth - your data
[LAT,LON] = meshgrid(lat,long);         % create 2D matrices
DP = griddata(lat,long,depth,LAT,LON);  % calculate value at each grid point
contourf(LAT,LON,DP)

[Jake]

Thank you! Your code is clear but why do I get a figure like this?

[darova]

Sorry, my bad. Try this:

% lat, long, depth - your data
lat1 = linspace(min(lat),max(lat),20);
lon1 = linspace(min(lon),max(lon),20);
[LAT,LON] = meshgrid(lat1,lon1);        % create 2D matrices
DP = griddata(lat,long,depth,LAT,LON);  % calculate value at each grid point
contourf(LAT,LON,DP)

[Jake]

Great! I think this is what I was looking for!

I shall, however, re-modify this accordingly. Would you recommend any references or pointers that I can follow to modify these outputs? Like adding legends, changing colors, adding labels etc. (Pardon me for the rookie question)

Thank you so much!

[darova]

What do you mean exactly?

surf(LAT,LON,DP,'facecolor','r')            % change all surface color to 'red'
legend('my data')                           % add legend
colorbar                                    % turn on colorbar
xlabel('X axis')                            % show axis label
ylabel('Y axis')

MATLAB has good help page. I use it all the time

[Jake]

This is exactly what I meant! I honestly didn't expect a code from you because I already took a lot of your time :)

Thanks a bunch. This saved the day!

[Ke Wei Ong]

May I know what is the unit in the legend, is it in meter or milimeter?