3d plotting of Lat, Long and depth

Hi,

I am trying to create a 3D plot - please see attached image.

However, i need to flip the scale so that the depth (km) increases downwards and I need to plot it in a 1:1 aspect ratio as all 3 axis are not equal in reality... Does anyone know how to do this?

Eventually i will need to plot elipsoid errors around these data points - if anyone has any experience with this, then I would be extremely grateful if you could share how you did it!

Many thanks!!

Answer 1

[Cris LaPierre]

Try this:

axis equal
ax = gca;
ax.ZDir = 'reverse';

[P_L]

Hi Cris, thank you for getting back to me!

I couldn't get the 'axis equal' code to't work.. my Lat and Long data are in degrees and my depth is in km. 1 deg ~ 111km. Do you know if there's a way to successfully plot both of these scales together?

Please see my data/ code attached

Many thanks!!

%% Data
Lat=[40.758853	40.763073	40.761671	40.760265	40.763082	40.758853	40.758853	40.756036	40.761671	40.761677	40.763085	40.763082	40.760265	40.758853	40.753203];
Long=[30.396377	30.39452	30.400074	30.401927	30.405623	30.396377	30.396377	30.392681	30.400074	30.407476	30.409325	30.405623	30.401927	30.396377	30.374183];
Depth=[10.623437	11.313867	11.136328	10.248633	10.84043	10.623437	12.201562	10.347266	11.373047	10.426172	10.288086	10.011914	10.011914	9.992187	11.807031];
%% Script
figure (1)
scatter3(Long(:), Lat(:), Depth(:),'o','MarkerEdgeColor','k', 'MarkerFaceColor',[0 .75 .75]);
%axis equal
ax = gca;
ax.ZDir = 'reverse';
xlabel('Long (deg)') 
ylabel('Lat (deg)') 
zlabel('Depth (km)')
%grid on

[Cris LaPierre]

Let's be clear: axis equal is working just fine, it's just not creating the result you want. As the name implies, it makes the step size the same on every axis, resulting in a visually scaled plot. It knows nothing about units.

Since you know the relationship between the two units (1deg = 111km), you can plot with everything being the same units (I'd convert km to degree). I would then update the Z tick labels to be in degrees (current value*111).

Just note, manually updating your labels means they won't automatically update if additional data is added or if the figure is resized. Make sure you have your final image before changing them.

%% Data
Lat=[40.758853	40.763073	40.761671	40.760265	40.763082	40.758853	40.758853	40.756036	40.761671	40.761677	40.763085	40.763082	40.760265	40.758853	40.753203];
Long=[30.396377	30.39452	30.400074	30.401927	30.405623	30.396377	30.396377	30.392681	30.400074	30.407476	30.409325	30.405623	30.401927	30.396377	30.374183];
Depth=[10.623437	11.313867	11.136328	10.248633	10.84043	10.623437	12.201562	10.347266	11.373047	10.426172	10.288086	10.011914	10.011914	9.992187	11.807031];

%% Script
scale = 111; % km/deg
scatter3(Long(:), Lat(:), Depth(:)/scale,'MarkerEdgeColor','k', 'MarkerFaceColor',[0 .75 .75]);
axis equal
ax = gca;
ax.ZDir = 'reverse';
zVal = str2double(ax.ZTickLabel)*scale;
ax.ZTickLabel = num2str(zVal);
xlabel('Long (deg)') 
ylabel('Lat (deg)') 
zlabel('Depth (km)')
%grid on

[Cris LaPierre]

Actually, I think it would be better to set the tick labels this way:

zval = [9.5:.5:12.5]';
ax.ZTick = zval/scale;
ax.ZTickLabel = num2str(zval);

[P_L]

Hi Chris, I'm so sorry for the delayed response. Your script suggestions were very helpful!! Please find attched of the result with your suggestions. I have tried rotating the image and moving it but for some reason, the depth axis does show. Do you know why it would do this? please see attcahed.

Many Many Thanks

:)

[Cris LaPierre]

Could you share your code? Did you scale your Z values correctly? What version of MATLAB are you using?

It works as expected for me.

[P_L]

Hi Chris,

Problem solved!! Thank you so much !!