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Home - General / All posts - Profile of a Line - overlay line on raster
GeoKeys8 post(s)
#23-Jun-20 03:11

In Manifold 9 - how do I join a line to a dem? I am ultimately trying to create an elevation profile of a line. I can see this in: http://www.georeference.org/doc/profiles_and_elevations.htm, but not in version 9. Can someone point me in the right direction?

Thanks,

Dimitri

6,064 post(s)
#23-Jun-20 05:56

There's no point and click dialog to do that in 9 yet. You could do that using a mix of dialogs or SQL, but it would be complex. For example, in multiple steps you could transform a line into a sequence of points, then transfer height values from the raster to those points and then visualize the sequence of heights in a charting package.

GeoKeys8 post(s)
#23-Jun-20 08:53

Ok, thanks.

tjhb

9,289 post(s)
#23-Jun-20 09:17

It might be a bit complex, but not very, and moreover it has already been robustly done.

If the OP posts test data, I will post code to do it.

This is not an isolated case, and it is why Manifold should start curating code as well as creating code.

You've made a tool. Keeping everything ego is just silly.

GeoKeys8 post(s)
#24-Jun-20 08:37

What do you need to do this? Just a dem with a polyline in a manifold file?

tjhb

9,289 post(s)
#24-Jun-20 09:08

Yes, and both can be tiny. But as much detail as possible would be good. I.e. a DEM with noticeable relief, and a line that is not very straight (rather than leaving that as a hard case for later).

Sloots

470 post(s)
#24-Jun-20 12:25

Here some test data and a query that generates a table of points every 50m along the line with the corresponding height. I used Excel to create the chart. A good start for a better, more comprehensive approach (multiple lines, how to dela with missing values etc.)

Chris

Attachments:
profile.map
profile.png


http://www.mppng.nl/manifold/pointlabeler

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