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Need Help in GIS: how to terrace DEM

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#1
akmal21987

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hello all, i now currently using ArcGIS for mapping, to complete my thesis for my degree i need to do terracing of the DEM so that 3d image generated will have terraced effect for hill planning..anyone can give suggestion how this can be done?

#2
David Medeiros

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hello all, i now currently using ArcGIS for mapping, to complete my thesis for my degree i need to do terracing of the DEM so that 3d image generated will have terraced effect for hill planning..anyone can give suggestion how this can be done?


Not having Arc in front of me right now this is a total stab in the dark, but where I might look first: you could create contour polygons from your DEM then "extrude between" in 3d analyst (assuming you have 3d analyst extension).

GIS Reference and Instruction Specialist, Stanford Geospatial Center.

 

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#3
akmal21987

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here the example what i ask about
Posted Image +Posted Image
=Posted Image

DEM file used with shapefile containing contour line to cut out/terraced several area on the DEM so that result will appear as shown

#4
David Medeiros

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Ok, I see what you need now. I'm once again not at work where I can experiment with this but I think you can do this by creating a separate polygon of each terrace area, assigning it a Z value for it's elevation and merging that with the DEM to change the values at those cells. Not sure of what the correct tool is though or if you will need to change the input polygons to raster first.

Take a look at the Raster Calculator, it may do what you want:
http://help.arcgis.c...000000z7000000/

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#5
J Wallace

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David is on the right track - you should be able to do this without spatial or 3d analyst: Create polygons for the terraced areas and give them an appropriate elevation attribute (equal to the elevation of your raster dataset at the terraced height). Convert the polygons to raster and then access Arctoolbox as follows: Data management tools - Raster - Raster dataset - mosaic to new raster. Make sure that the mosaic operator is set to your newly created terrace rasters (either 'first' or 'last' depending on how you added the layers to the toolbox), and your output mosaic should be a nicely terraced surface.

Good luck.




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