topic Re: Why does Contour With Barriers Not Avoid Barriers in ArcGIS Spatial Analyst Questions

Why does Contour With Barriers Not Avoid Barriers

JasonEvans — Fri, 07 Aug 2015 20:22:22 GMT

In trying to create contours of a 10m resolution DEM, I am having issues with contours in a lake. I have tried to use contour with barriers in spatial analyst and there is no change when using that with water resource shapes or polygons versus no barriers. Can anybody help with why this may be the case?

Thanks.

Re: Why does Contour With Barriers Not Avoid Barriers

DanPatterson_Retired — Fri, 07 Aug 2015 20:32:48 GMT

There are so many limits in the help documentation, you will have to be more specific as to which options you used

http://desktop.arcgis.com/en/desktop/latest/tools/spatial-analyst-toolbox/contour-with-barriers.htm

Re: Why does Contour With Barriers Not Avoid Barriers

XanderBakker — Fri, 07 Aug 2015 20:41:33 GMT

What are the exact issue that you are having with this tool? I don't think using a barrier like a lake (outline) will ave much effect since...

... the inclusion of barrier features allows you to independently generate contours on either side of a barrier.

The border of a like will be a the same elevation resulting in contours inside and outside your lake, like would happen without using the barrier.

So, what do you want to achieve?

Re: Why does Contour With Barriers Not Avoid Barriers

JasonEvans — Fri, 07 Aug 2015 20:46:06 GMT

I have tried using a polyline feature as well as shapefile as the input barrier features. The contour type was a polyline with a base contour of 0, interval of 10m, and either an indexed contour nor explicit values.

Re: Why does Contour With Barriers Not Avoid Barriers

JasonEvans — Fri, 07 Aug 2015 20:49:12 GMT

I would like the contours to follow the lake, but as it currently stands, they are cross cutting the feature. The lake is a known elevation which meshes with the contours that should fall there. However, with the DEM interpolation, it does not show as a flat area since it is a very shallow lake- I suspect there was some interference with the data or through the interpolation in raster creation.

I would like to achieve a boundary up to the lake so that the fictitious contours within the lake can be removed without simply cutting the contour lines that cross the lake's boundary.

The contours themselves are no different than the contour function and cross the lake in the same locations.

Re: Why does Contour With Barriers Not Avoid Barriers

DanPatterson_Retired — Sat, 08 Aug 2015 02:33:54 GMT

But the DEM isn't reflecting the water surface then, A workaround is to make a lake of known elevation and replace the elevation and add the that surface to the DEM prior to interpolating...you will still have fiddly bits around the edge of the lake as you would if the lake were replaced as nodata values as documented in the help files.