topic Re: Zonal statistics query in ArcGIS Spatial Analyst Questions

Zonal statistics query

MS10 — Thu, 21 Apr 2016 19:17:48 GMT

Hi, I have two rasters (Hyrdological Soil Group (HSG) and Land Cover) and i'm trying to find the average HSG for each land cover type. The HSG raster contains the values 2,3 and 4 and there are 23 different land cover types. I've tried using zonal statistics using the mean statistics type, but this results in mean values ranging from 2.58 to 3.47. I would like just single numbers (i.e 2,3 or 4) for each land cover type, is there a way around this?

Thanks.

Re: Zonal statistics query

DanPatterson_Retired — Thu, 21 Apr 2016 21:17:47 GMT

When working with categorical data, (such as your HSG data) being summarized with another categorical data set (like you Land Covers)... you cannot calculate a 'mean' class, since categorical data has no concept of mean. Sorry, but this just wrong.

You can use zonal statistics to determine the ... majority ... the minority... the variety

All other measures (aka, mean, range, std dev, var etc etc ) require interval/ratio data.

You can examine Con if you need condition checking, but you have (3 HSG * 23 LC ) combinations to work with.

Re: Zonal statistics query

DanPatterson_Retired — Mon, 25 Apr 2016 22:13:45 GMT

also posted here arcgis desktop - Zonal statistics query - Geographic Information Systems Stack Exchange