topic Re: Divide raster values based on municipality boundaries in ArcMap Questions

Divide raster values based on municipality boundaries

Deepa — Tue, 01 Mar 2022 12:58:53 GMT

Hi,

I have a raster file of a county with value 1 (Best sites to build rails) and NoData (unsuitable areas for rails). I also have a shape file of all the municipalities within this county. I would like to combine these files such that the final attribute table of the raster will have the cell counts with value 1 for each municipality. I can export each municipality and then combine with the raster to solve this. But is there a better and easy way to solve this?

Thank you!

Re: Divide raster values based on municipality boundaries

DavidPike — Tue, 01 Mar 2022 14:00:42 GMT

Can you better describe your intended final output and possibly provide screenshots.

Re: Divide raster values based on municipality boundaries

Deepa — Tue, 01 Mar 2022 14:22:00 GMT

Right now, i have raster file with values 1 for a county. There are some NoData within the county which i am not interested in further analysis. Attribute table looks like this :

OBJECTID	VALUE	COUNT
1	1	20

Within the county there are 3 municipalities and i have a shape file of this. Attribute table looks like this:

OBJECTID	Shape	Municipality_names
1	Polygon	ABC
2	Polygon	DEF
3	Polygon	GHI

I would like to combine them spatially such ´that i get a final attribute table like this:

OBJECTID	Municipality_names	Value	Count
1	ABC	1	10
2	DEF	1	5
3	GHI	1	5

Re: Divide raster values based on municipality boundaries

DavidPike — Tue, 01 Mar 2022 14:55:50 GMT

You could possibly vectorise your raster data and utilise Tabulate Intersection (Analysis)—ArcGIS Pro | Documentation

or Zonal Statistics as Table (Spatial Analyst)—ArcGIS Pro | Documentation

Re: Divide raster values based on municipality boundaries

JeffHouser — Tue, 01 Mar 2022 15:37:04 GMT

I have not tried this, but have you looked into "Spatial Analyst Tools - Zonal - Zonal Statistics as Table".
https://gis.stackexchange.com/questions/251796/extract-raster-information-based-on-polygon-features

Last step, is to do a tabular join back to the Raster data. Again, I have not done this, but it seemed appropriate to what you're trying to do? This functionality, if it works, may prevent the need to vectorize the raster date set.

Re: Divide raster values based on municipality boundaries

Deepa — Wed, 02 Mar 2022 07:54:46 GMT

Thanks David and Jeff 🙂

It worked with Zonal statistics as table using my polygon file of municipalities and raster file with values.