I have a geological setting where I would like to add a lithology to an existing map. I already have the 3D polylines from my geological map and the DEM I now want to add another polyline between two outcrops that occurs like 20 m below one polyline and follows the topography.

Picture one shows the 3D model and two the 2D one. The black line is what i would like to create automated with ArcGIS Desktop.

Anyone an idea how to do that?

enter image description here

enter image description here

  • Are you talking about some kind of 3D contour line that will be below 20m of one of your polyline and follows the topography of your area ? – Saad Asif Sep 13 '18 at 11:46
  • yeah that sounds exactly like i would like to have it – Ole Sch Sep 13 '18 at 12:11
  • @Polygeo I am attempting to post solution. It won't let me add picture to it. Tried Chrome and Internet Explorer. Same result. – FelixIP Sep 13 '18 at 21:57
  • If you like to add a 3D contour line you can simply create contours between the two 3D polylines using the DEM and select your desire 20 m contour then interpolate it on the DEM surface and copy it to your 3D polyline layer. – Saad Asif Sep 14 '18 at 4:53
  • @SaadAsif it's not that easy the problem is that the other lines are not leven and cut through some contour lines – Ole Sch Sep 14 '18 at 5:15

Ok, it works with tiny images (Bad news), anyway. If you line climbs gently along contours, like kerb below does:

enter image description here

Try this after splitting it into smaller bits:

arcpy.InterpolateShape_3d("dem", "splits", "C:/SCRATCH/splits3d.shp")
arcpy.AddZInformation_3d("splits3d", "Z_MEAN")
arcpy.gp.EucAllocation_sa("splits3d", "C:/SCRATCH/ea", "", "", "2", "FID")
arcpy.AddJoin_management("ea", "VALUE", "splits3d", "FID")
arcpy.gp.Lookup_sa("ea", "splits3d.Z_Mean", "C:/SCRATCH/SURFACE")
arcpy.gp.RasterCalculator_sa('Con("dem"  <=  "SURFACE" - 3,1)', "C:/SCRATCH/one")

This will produce something very similar to what you want:

enter image description here

  • sry for the late answer. Is there any way you could tell me the normal commands i can you. I have never worked with python. – Ole Sch Sep 17 '18 at 6:52
  • These are normal commands, tools. – FelixIP Sep 17 '18 at 8:13

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