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I have a DEM in the form of a raster that I would like to update in certain locations. Ideally, I'd like to be able to create a separate polygon or point shapefile with the values, in the correct spatial location, to update the original DEM with. Is there a way to do this?
I have a spatial analyst extension and ET Geowizards. I do not have 3D Analyst.
I need to use ArcGIS for this.
You can use either polygons or points, which you choose depends on whether you need to update large areas or just individual cells.
Once you've got your points/polygons created with an attribute table column with the values you want to use to replace values in the DEM with, convert the feature class to raster with the Feature to Raster tool (or the Point to Raster/Polygon to Raster tools). Make sure you set the appropriate environments - Processing Extent->Extent and Snap Raster and Raster Analysis->Cellsize - to your DEM and set the correct column as the value field in the tool.
You can then use a statement like the following in the Raster Calculator:
Con(IsNull("newvalues"), "DEM", "newvalues")
This means: If a cell in the "newvalues" raster is NoData, use the "DEM" cell value, else use "newvalues" cell value.
based on your question, it seems like you want to convert raster data into vector where the raster value represent as it's attribute.. you can use raster to point or polygon tool on arcgis, the pixel value will be replace as grid code on it's attribute.. the resolution of dem will impact on distancd between point...
