Plot line with points at given distance

Hi all,

I need to find a way to plot markers along a line (river course; attached file) with a given distance, e.g. each 500m.

Is there a way to extract these values. The find function does not work in this situation since I only get an empty double column vector. I've used the TopoToolbox before, so the dataset is a STREAMobj which might be diffucult to read for one who hasn't the toolbox installed.

I tried to plot new points with spacing, but since the river is not smoothed and also should not be, point spacing starts and every new edge.

plot(Facet1)
hold on 
spacing = 500;
plot(Facet1(1:spacing:end,1),'ro')

In advance thanks for your help.

[Voss]

Is this an accurate representation of your data?

S = load('NEU.mat')

Warning: Variable 'NEU' originally saved as a STREAMobj cannot be instantiated as an object and will be read in as a uint32.

S = struct with fields:
    NEU: [6×1 uint32]

S.NEU

ans = 6×1

3707764736 2 1 1 1 3

[Steven Lord]

The MATLAB that is used to run code in MATLAB Answers doesn't have TopoToolbox installed, so it doesn't know how to recreate a STREAMobj object that was created using that toolbox and saved in the MAT-file.

[Voss]

Ah, I see. I thought all the toolboxes were available here, so that's good to know.

[Ricco Blass]

Yes I updated my question. Should have mentioned that before.

Answer 1

[Wolfgang Schwanghart]

Since you are working with TopoToolbox, you might want to use the function getlocation. If you have a STREAMobj S, then you can retrieve points at a distance of 500 m as follows:

DEM = GRIDobj('srtm_bigtujunga30m_utm11.tif');
FD = FLOWobj(DEM);
S = STREAMobj(FD,'minarea',1000);
S = klargestconncomps(trunk(S));
[x,y,val] = getlocation(S,[0:500:max(S.distance)]);
plot(S)
hold on
plot(x,y,'ok','MarkerFaceColor',[.5 .5 .5])
axis image

[Ricco Blass]

That's exactely what I was looking for.

Thanks a lot!!

Answer 2

[Catalytic]

This may help,

https://www.mathworks.com/matlabcentral/fileexchange/34874-interparc