I have a DEM in arcmap and cross section of a river which flows on the Dem in Hecras.

I now the cross sections are more accurate. I want to make a DEM from some of my cross sections and stitch it on my original Dem to analyze 2d flow in the other hydraulic soft ware.

How can I make Dem from cross sections and How can I stitch it?

  • sounds like an interpolation/kriging problem – user1269942 Oct 21 '14 at 4:12

For the task, it is of course important that you have a sampling of profiles that is dense enough to ensure that the result becomes precise enough. If you have a 1,6m DEM and profiles pr. 100 m. then your profiles may be more precise, but your overall uncertainty will be huge.

If you have sufficient data in profiles, then you create points along your profiles with the z-value and interpolate a raster DEM based on the data. Make sure to use the same reference grid as your existing DEM. Then you do a simple condition statement afterwards, where you patch the two together.

The choice of interpolation method is optional and should be based on analysis of data, but generally i would go for Krieging.

  • Hi Morten, what do you mean by profiles? I have just cross sections from hec ras. do you mean i have to connect these cross sections and make some longitudinal profiles? thanks for your response. cheers – Mike Oct 21 '14 at 8:50
  • 1
    By profiles i mean your cross sections. These must be turned into points with z value, and interpolated uppon... – Morten Fuglsang Oct 21 '14 at 19:29

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