I am using ArcGIS 10.2 in order to create soil management zones for farmers. when I use the raster to polygon tool it creates small triangles out of the polygons and jagged edges that are very unrealistic looking zones. 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 change these zones from raster to vector and look realistic?

  • Can you provide a screenshot of your input raster, as well as indication what the values of the raster cells are? An output of your current results might help as well. It's hard to offer suggestions without seeing the actual problem. – Chris W May 30 '15 at 5:23

First of all.... Is this using the generalize polygons toggle or not? Toggling this on might be good enough for your purpose. Keep in mind the intended data scale relative to presentation scale. My suggestion below is purely for presentation. Make-up on a pig .... No offense meant...

Although this is categorical data, you might get a more natural looking output from an interpolation rather than a conversion. Not sure how your SMUs are organized, but you would need to have each type with a unique number, possibly arranged in some assumed sorting order by particle size. Then create contours and polygonize those. If attributes don't come along happily, convert your raster to point and join the points to the polygons. Probably have some artifacting where mud turns to bedrock or boulder .... That type of thing. You could also try resampling your raster to a smaller cell size and messing with your interpolation type. Nearest neighbor is what you should be using, but depending on the change in cell size and how much smoothing you are looking for.... Something else might give you a more natural looking result...keep in mind this is no longer data though.. Just illustrative

  • Mike The generalize option you mentioned do you mean smooth polygon during the raster to polygon conversion? – Andy May 30 '15 at 2:20
  • Yes, it is just a check box in the raster to polygon tool. It has no modifiable parameters, so it does what it does. Proceeded by a resampling to a smaller cell size and a few iterations of expanding and thinning groups it should smooth a little better. – Mike May 30 '15 at 15:21

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