Bathymetric data into a surface plot

Hi,

I have attached a folder which is my given bathymetric data for a seabed. I want to make this into a surface plot or a contour map. I am new to matlab and have little experience with the software, but understand that it is a good software for this particular problem.

If anyone could assit me with this, that would be great.

Thankyou,

Ruari Skinner

Answer 1

[Star Strider]

Try this:

[D,S] = xlsread('Bathymetric data (XYZ).xlsx');
Lon = D(:,1);
Lat = D(:,2);
Dep = D(:,3);

figure
plot3(Lon, Lat, Dep, '.')
grid on
view(35,25)
title('Exploratory Plot')

xLon = linspace(min(Lon), max(Lon), 1E+3);
yLat = linspace(min(Lat), max(Lat), 1E+3);
[X,Y] = meshgrid(xLon, yLat);

zDep = griddata(Lon, Lat, Dep, X, Y);

figure
mesh(X, Y, zDep)
grid on
view(35,25)
title('Mesh Plot')

figure
mesh(X, Y, zDep)
hold on
contour3(X, Y, zDep, 20, 'k', 'LineWidth',2)
hold off
grid on
view(35,25)
title('Mesh Plot With Contours')

This uses the griddata function to create the surface necessary to do the mesh plot. The contour3 plot draws contours. You can specify the contours you want (if you want any at all). I plotted them simply out of my own curiosity.

Experiment to get the result you want.

[Ruari Skinner]

Thankyou,

I will try this and get back to you.

[Star Strider]

My pleasure.

[Ruari Skinner]

Hi,

I am struglging to run this with an Error code stating

>> PrincessParade_bathymetry

Index in position 2 exceeds array bounds (must not exceed 1).

Error in PrincessParade_bathymetry (line 3)

Lat = D(:,2);

[Star Strider]

My code runs without error with the data you provided as ‘Bathymetric data (XYZ).xlsx’. Use it and the xlsread call I used.

I have no idea what the problem could be with your code, or your implementation of my code, since you didn’t post it.

[Ruari Skinner]

Sorry I had simple spelling error.

Thank you for your support and quick responce, much appreciated.

Ruari

[Star Strider]

My pleasure.

If my Answer helped you solve your problem, please Accept it!

[Guilherme de Melo]

Dear Star Strider,

I am using this your example to plot a bathymetric data mine as a 2d map colored using the depth variation. I have used the following commands to read e plot:

[X_bathy, Y_bathy, Z_bathy] = grdread2('file.grd');

[xLon, yLat] = meshgrid(X_bathy,Y_bathy);

figure(20); mesh(xLon, yLat, Z_bathy);

it is plotting but it is a 3d figure. Do you know how can I change for one map format? X and Y are in geographical coordinates in degree, and Z in meter.

I will be very thankful for you help.

Guilherme

[Star Strider]

@Guilherme Weber Sampaio de Melo — I do not have the Mapping Toolbox, so I have no experience with it or its functions. This problem used Cartesian coordinates, so I was able to work with it.

You might be able to use the view function (specifically view(0,90)) to get a ‘top-down’ view of the surface that may be map-compatible. (Also, the scatteredInterpolant function may be better than griddata for these problems, so it might be worth experimenting with it to get a more accurate representation of the surface.)