topic Re: HEC-Geo HMS Curve number grid problem in Water Resources Questions

HEC-Geo HMS Curve number grid problem

MS10 — Fri, 22 Apr 2016 22:04:00 GMT

Hi, i'm trying to create a curve number grid and have followed this guide (https://web.ics.purdue.edu/~vmerwade/education/cngrid.pdf), however i'm at the last stage and when i go to create the curve number grid it just runs and doesnt finish. Both the HydroDEM and Soil/Land use polygon are in the same coordinate system (British National Grid). I tried to clip the DEM to the Soil/LU polygon by converting the polygon to raster then using Clip, however the DEM doesn't Clip and stays the same. I had similar problems with Flow Accumulation weight grid, however clipping the weight grid worked in that instance. I'm not sure if the DEM not being the same exent would make a difference but does anyone have an idea to what is wrong?

Thanks

Re: HEC-Geo HMS Curve number grid problem

DanPatterson_Retired — Fri, 22 Apr 2016 22:13:11 GMT

the extents of the files are indeed important. You need to examine and report those. Also when using the clip tool in Arctoolbox, the environments (bottom of every tool dialog) need to be explicitly set regarding cell size, the extent and snap raster if appropriate.

Re: HEC-Geo HMS Curve number grid problem

MS10 — Fri, 22 Apr 2016 22:22:22 GMT

Hi,I imported the Soil /LU polygon and DEM into the Geodatabase that contained the CN Look up table and it seems to have worked. Thanks again.

Re: HEC-Geo HMS Curve number grid problem

DanPatterson_Retired — Fri, 22 Apr 2016 22:56:08 GMT

glad it worked