I produced a raster map representing estimates of the number inhabitants in pixels of 100x100 meter and I want to calculate the total of inhabitants per administrative units that are represented by polygons such as those shown in the picture. After conver

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05-19-2018 09:16 AM
JotaUs
by
New Contributor

I produced a raster map representing estimates of the number inhabitants in pixels of 100x100 meter and I want to calculate the total of inhabitants per administrative units that are represented by polygons such as those shown in the picture. After converting those polygons into a raster layer (with a resolution of 100 meter) I'm using Zonal Statistic as Table in ArcGIS to calculate the number of inhabitants per administrative unit. The resultant table has fewer lines than the number of administrative units represented in the raster layer. Therefore I'm losing information for administrative units having an area below 28500 square meters or for administrative units with an irregular geometry such as those highlighted in the picture. The problem persists when I convert the administrative units into a raster layer with a resolution of 25 meter.

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6 Replies
DanPatterson_Retired
MVP Esteemed Contributor

It is best to convert the zones to a raster first, setting the cell size, extent and snap raster before beginning.

http://pro.arcgis.com/en/pro-app/tool-reference/spatial-analyst/zonal-statistics-as-table.htm

If this isn't done, then you may not get exactly what you want

JotaUs
by
New Contributor

Thanks,

I did all of that before posting the question actually.

Yet, any thoughts?

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DanPatterson_Retired
MVP Esteemed Contributor

The image doesn't show the raster version of the administrative units does it?

ADDENDUM

There are 58 bugs covering all incarnations of ArcMap and PRO, but none that cover your situation

 

https://support.esri.com/en/Search-Results#search?q=zonal statistics as table&content-type=Bugs

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JotaUs
by
New Contributor

The image itself no but I have done those procedures before. I believe this may happen due to the irregular geometries of the polygons. I am not sure if there is any way to tackle this issue. I have done the conversion to raster in equally area of the minimum polygon area but still no resolution.

Thanks

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XanderBakker
Esri Esteemed Contributor

If possible, attach the data (or a sample of the data) to the thread so we can have a look what is going on.

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JotaUs
by
New Contributor

Thanks Xander. I have talked with my colleagues and in the near time would be complicated to share the data as we have limited time to prepare it (we work with large datasets). Anyway, if I have a chance, I will certainly do it. I want to return to this point later as it is important to find a solution.

Thanks again

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