Problems creating realistic polygons for soil management zones using arcGIS 10.2 raster to polygon

3263
3
05-29-2015 02:34 PM
Highlighted
New Contributor

  raster.JPG

I am using ArcGIS 10.2 in order to create soil management zones for farmers. The above image represents realistic looking management zones however when I use the raster to polygon tool it create small triangles and very unrealistic looking zones. See image below. I have used the smooth polygon tool, as well as the nibble, focal statistics and majority filter while the files is still a raster in order to reduce the number of zones. Any ideas on an effective way to do this?

Thanksraster.JPG

Reply
0 Kudos
3 Replies
Highlighted
Frequent Contributor

Have you tried not simplifying the polygons when converting from raster to polygon(No_Similify)?  You would have a more complex geometry, but as long as you are viewing at the same scale as the raster, it should look near identical to your existing raster.  Once you zoomed it would look more jagged of course, but at a farther out scale, it would work.

You said your original raster looked like realistic management zones, so that might work for you.  If you wanted more organic looking polygons at a zoomed in level, you could use the smooth polygon tool or smooth in the advanced editor toolbar

Highlighted
Occasional Contributor III

Interesting, I wouldn't expect this to happen either.

Looks like you used Geostatistical Analyst to get the surface in your first image. Outputs of Geostatistical Analyst tools are not a rasters as such, but geostatistical layers. For further processing with Spatial Analyst tools it is better to export this layer to an actual raster​​​. Then you can use whatever tools you need (although which tools to use a question in itself) and possibly Reclassify​​​​ and eventually run Raster to Polygon​ with simplify="NO_SIMPLIFY". This should produce polygons with boundaries following cell edges exactly. Then you can Smooth Polygon​ or Simplify Polygon​ for better cartographic representation.

Forgive me if you have done all that and your results are as you posted.

Hope this helps,

Filip.

Highlighted
MVP Esteemed Contributor

Your cell size may be coarse relative to what you want...have you tried to resample to a finer grid size prior to conversion and applying other suggestions​