Color coded 3D scatterplot

Produces a 3D scatterplot of XYZ data with varying colors

Description

A 3D scatter plot of a Cartesian data set is drawn. The data points are sorted by color so that plot3 is called once for each group of points that map to the same color. Execution time is significantly reduced for large data sets. By default the points are colored according to their distance from the XY plane. This can changed with the 'ColorData' property. Additionally the upper and lower limits of the color range can be specified. This is useful for creating a series of plots with the same coloring.

The example plot is produced by the following code.

   figure('color','white');
   [x,y,z] = peaks(101);
   c = gradient(z);
   k = hypot(x,y)<3;
   plot3k({x(k) y(k) z(k)},...
      'ColorData',c(k),'ColorRange',[-0.5 0.5],'Marker',{'o',2},...
      'Labels',{'Peaks','Radius','','Intensity','Lux'},...
      'PlotProps',{'FontSize',12});

Plot3k is based on plot3c by Uli Theune.

Acknowledgements

Plot3c inspired this file.

• MATLAB release: MATLAB 7.7 (R2008b)

[Nick]

 

[Amir]

works great!

[Ken Garrard]

Thanks for the suggestion Val. I'll update the submission.

[Val Schmidt]

This is a fantastic utility - something that should be incorporated into MATLAB proper, as scatter3 is awful.

I do recommend one change however. Currently, plot3k calls "hold on" prior to plotting anything which means you'll always add to whatever figure window is active. Since this is not the default behavior of MATLAB I find it a hassle.

The fix is to move 'hold on' on line 164 so the plotting loop looks like this:

-------snip----------
% plot data points in groups by color map index
s = 1; % index of 1st point in a color group
for k = 1:length(dLix) % loop over each non-empty color group
plot3(L(s:dLix(k),1), ... % call plot3 once for each color group
L(s:dLix(k),2), ...
L(s:dLix(k),3), ...
mark_ch, ...
'MarkerSize',mark_sz, ...
'MarkerEdgeColor',cmap(L(s,4),:), ... % same marker color from cmap
'MarkerFaceColor',cmap(L(s,4),:) ); % for all points in group
s = dLix(k)+1; % next group starts at next point
if k==1
hold on; % add points to one set of axes
end
end
hold off;
----------snip----------

[Alexander]

Great code. One small improvement:
Change length(L) to size(L,1) on 96 and 141 lines. Otherwise, it's not working with one data point

[James]

 

[Navneet Viswan]

Is it possible to use this code to scan images with laser stripe in it and plot out the 3D point cloud of the laser traced portion? with depth?

Kindly help me out

[daniel]

After trying and failing to plot my data (3e6 points) using scatter3, this little guy did it for my lickety-split. Is a 4D set, so plotting first 3 dimensions as spatial, and fourth as color. Just had to make sure my nargs matched up via cells, so did {data(:,1) data(:,2) data(:,3)} as first arg to plot3k, and data(:,4) as second for color.

A+ rating from this matlab user.

[Joseph Miller]

Simple, fast and clean. VERY good job! Thank you!

[Nathan]

 

[Nathan]

minor grid does not show up on Z-axis when Zscale is set to log
(i.e. set(gca,'zscale','log');

any idea why this is occuring?

[Peng Huang]

I would suggest to change "length(L)" to "size(L,1)" since when points are too less (i.e. less than 3), error will happen. Besides that, it is great! Thanks:)

[Vishesh Vikas]

Very good - its way quicker than scatter3. Uses much less memory :)

[Alvaro Canivell]

Very useful indeed !

Something I was missing in it:

- A label for the color bar, that could be passed in the 'strs' together with the title and the rest of the labels.

If somebody wants that, just tell me, I added that

Thanks again !

[Le]

very good job! thank you!

[aaaaa]

 

[Adam Pilchak]

excellent file.
For those interested in additional functionality in terms of viewing contours and slices through 3d data, check out:
http://www.paraview.org

[Jveer]

very nice indeed! any chance of further speed optimization?

[Shazux The Great]

one that you should never miss!

[Abel Brown]

Holy Jehosaphat!! worked outta the box! The funktion did exactly what i just spent the last hour trying to do! what a fantastic function for scientifik data! you're my hero!!!!

thanks x 10!

[Mike Ross]

Exactly what I was looking for. Thank you.

[Esben Almkvist]

Nice!
I would add a:
if nargout>0
g = gcf;
end
That way you get a cleaner function if you don't need the output.

[Tim A]

Thanks a lot, very useful

[Joseph Marks]

It "rocks"; it allows a "surf"-like plot without the hassles and inaccuracies of preppoing the dating over a regular grid!
First-rate work.

[Eric DeGiuli]

Great, does just what I wanted.

[Alexander K.]

Very useful function

[Matteo Tajana]

thank you, I've been looking for such a function for ages! ;-)

[sylvio berlusconi]

your are a genious

[Josiah Yoder]

Just what I was looking for - works great.

[Daniel B]

Great function. Work well and is fast.

[oh kwoun]