topic Zonal Stats as Table Help in ArcGIS Spatial Analyst Questions

Zonal Stats as Table Help

JakeNelson1 — Wed, 27 Mar 2013 23:40:58 GMT

Hello,

I am working on a project that requires me to extract raster values to a grid of polygon cells I created using the fishnet tool.

The raster data I am working with is oceanic Chlorophyll-a values.

The polygon grid that I am using extends from land to the ocean meaning there are no data values on land

The problem I am running into is that when I run the zone statistics to table tool, it is ignoring the no data values and not recording them in the output table. Is there a way to get some sort of value for all of the polygon cells I am extracting values to even if the underlying raster value is no data? Any help is much appreciated.

Re: Zonal Stats as Table Help

curtvprice — Thu, 28 Mar 2013 04:07:27 GMT

... when I run the zone statistics to table tool, it is ignoring the no data values and not recording them in the output table. Is there a way to get some sort of value for all of the polygon cells I am extracting values to even if the underlying raster value is no data?

I think you want to fill in data so you will have a row for each model grid polygon, even if there were no data cells for that polygon, right?

If you want to "fill in" missing value codes (say, -9999) for the cells that have no stats results (because there is no data to calculate stats for those cells) your only solution I can think of is to select the polygons with no matching statistic, export those rows to a table, and append those rows to your Zonal Stats As Table output. If you append with the NO_TEST option, only fields that match (same name) will be copied. You could then select those "dummy" rows and populate a missing value code for the stats using the Calculate Field tool.

Hope this helps...

Re: Zonal Stats as Table Help

JakeNelson1 — Thu, 28 Mar 2013 23:19:11 GMT

That makes a lot of sense. I'll give that a go and see what I can come up with. Thank you for the response.