topic Re: multi part polygon to polygon in Geoprocessing Questions

multi part polygon to polygon

JeremyTibbetts1 — Mon, 13 Jun 2011 15:03:51 GMT

Hi,
I have a multi part polygon created from bathymetry data.

When I converted the raster to polygon, it created several small polygons (I have attached a sample of the polygon).

What I am looking to do its create one solid polygon from all of these parts, ei. no space in between the smaller polygons.

I was wondering if there is any way of doing this.

Thanks,
Jeremy

Re: multi part polygon to polygon

DuncanHornby — Wed, 15 Jun 2011 14:27:39 GMT

Jeremy,

Probably the easiest way is to reclassify your source raster dataset to create one big raster dataset of one value then covert that into the polygon?

Duncan

Re: multi part polygon to polygon

ChrisSnyder — Wed, 15 Jun 2011 15:53:04 GMT

Disn't look at the polygon, but maybe the Union tool with the "No_GAPS" option?

Re: multi part polygon to polygon

DanLee — Wed, 15 Jun 2011 16:52:39 GMT

If you have ArcGIS 9 or 10 with ArcInfo licensing, try Aggregate Polygons tool with an aggregation distance = 600m.

To go with the raster approach, perhaps you can try the Expand tool, followed by the Shrink tool in Spatial Analyst.
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//009z00000036000000.htm
http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//009z0000003m000000.htm
The Expand tool grows the raster areas so that they become connected/aggregated; the Shrink tool reduces the over-grown areas (shrinking back without disconnecting the areas). You need to figure out the suitable cell sizes.

In the resulting polygons contain small holes, you can use Eliminate Polygon Part tool (ArcGIS 10, Arcinfo licensing) to get rid of small holes.

Hope the above helps.