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I'm using a code to simulate flood events and I need to build two main files: one with the river channel width and another one with the bed elevation (both in ARC-info ascii raster format).

I've managed to create a new field in the attributes table and insert a constant width value, but when it comes to generate the raster grid with the bed elevation I'm lost. I've tried "Add surface information", "join" and "interpolate" tools so far, but it doesn't not work as I expected.

The final outcome has to be a ascii file with NoData cells (=-9999) for those areas where the river channel does not exist and bed elevation values for those cells where the river is present.

I have beginner-intermediate programming knowledge (VBA, DOS and a bit of Python mainly) and I'm working with ArcGIS 10.4.1; the final grid has to contain 1500 columns and 1000 rows, since I'm working with 6 tiles of 2 m resolution DEM data.

  • hm, and is that a (vector) feature layer with the channels as lines that you want to convert to those raster files? plus one dem for the area? – ThingumaBob Jul 6 '17 at 15:30
  • HI @ThingumaBob! Yeah, that's it: the river channel lines are in a shapefile that has been converted into a raster file. What I want is to "couple" that river channel raster cells to the ones in the DEM that contain the elevation data and generate a single file (ascii table format) with the river cells (containing the elevation) and nule values for the rest of the cells. Thanks for your answer and sorry if I wasn't clear with my question!!! – Elena Jul 6 '17 at 19:29
  • okay. I think you could use tools from the Extraction Toolset, if you have access to the Spatial Analyst extension. There is the 'Extract by mask' tool that effectively creates a grid with all cell values of an input raster (your DEM) that matches any non-NULL value in a mask raster (your channels). NULL values in the mask layer will be NULL values in the output raster. there is reference here. Might help. I haven't worked with ArcGis for a while and there might be other solutions that I don't know. – ThingumaBob Jul 7 '17 at 9:23
  • Just did it, it was exactly what I needed!! Thanks a lot!! – Elena Jul 7 '17 at 12:53
  • you're welcome! I'll copy my comment as an answer...would you accept it (it's all about reputation...,) ) – ThingumaBob Jul 7 '17 at 13:44
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I think you could use tools from the Extraction Toolset, if you have access to the Spatial Analyst extension.

There is the 'Extract by mask' tool that effectively creates a grid with all cell values of an input raster (your DEM) that matches any non-NULL value in a mask raster (your channels). NULL values in the mask layer will be NULL values in the output raster.
There is reference here.

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