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