[GIS] Generating Point from Centroid of Polygon falls outside of it

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I have a feature class of polygons within a geodatabase and I'm trying to generate points based on the centroid of the polygon using the Feature to Point tool in ArcGIS 9.3.

However, I end up with several points that fall just outside of the polygon.

Is this the wrong tool to be using for this application?

Also, am I making the wrong assumption about this tool generating points from the centroids of polygons?

Best Answer

The online help indicates that you must check the box to be INSIDE so that a point inside the polygon will be used for the output.

As @DanC commented:

The center of gravity can in fact fall outside the polygon. Think of a donut shape, with an empty hole in the middle of the circle polygon. The center of gravity would be there even though the polygon doesn't extend there.

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ArcPy – Creating Feature Class in File Geodatabase in ArcGIS Desktop with Arcgisscripting

I think your first problem is that you're appending ".shp" to your output geodatabase featureclass. Remove this and your problem may be solved.

...     
....
shpFile = "file_%s" % number  #--removed ".shp"
...
...the rest of your code here

Create a Point Within a Polygon in QGIS – How to

If you do not care about whether the point is a centroid or not, just use Vector -> ResearchTools -> Random Points. You may define to place a single point per each polygon in a layer. Also you may create centroids for initial polygons, delete points that do not intersect any polygon, save polygons without points as a separate layer, create random points for this polygosns and in the end copy these random points to centroids layer.

Best Answer

Related Solutions

ArcPy – Creating Feature Class in File Geodatabase in ArcGIS Desktop with Arcgisscripting

Create a Point Within a Polygon in QGIS – How to

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