topic Re: Image Classification question in Data Management Questions

Image Classification question

808707 — Tue, 21 May 2013 08:29:14 GMT

Hello,

I've carried out an image classification over a large area using aerial photographs.

I have a vector region layer representing all the parcels of land in that area.

What I want to be able to do is that for each polygon all the pixels under that polygon will be converted to the pixel value that currently represents the majority of pixels under that polygon.

Is this possible? Many thanks for any help.

Re: Image Classification question

AliciaMein — Wed, 22 May 2013 12:43:56 GMT

I have not run this to check, but I beleive you will be able to do this with the <Zonal Statistics> tool. Your zones will be your parcels, Input raster will be your value raster you want to analyze, and just choose majority.
Alicia

Re: Image Classification question

JeffreySwain — Wed, 22 May 2013 18:09:37 GMT

As previously mentioned, the zonal statistics as a table will work. Once the table is generated, you can join it back to the parcel polygon feature class. This should create the desired output.

Re: Image Classification question

808707 — Thu, 23 May 2013 08:38:51 GMT

Thanks to you both. I'll give it a go and let you know the outcome.

Re: Image Classification question

808707 — Fri, 24 May 2013 13:43:19 GMT

As previously mentioned, the zonal statistics as a table will work. Once the table is generated, you can join it back to the parcel polygon feature class. This should create the desired output.

Thanks this is working brilliantly.

Just one query though. I have been experimenting with both 'Zonal Statistics' and 'Zonal Statistics as Table' tools.

I'm developing a preference to the 'Zonal Statistics' tool as the results are immediately displayed in the map window.

Is there any reason why you recommended the 'Zonal Statistics as Table' tool instead of the 'Zonal Statistics' tool?

Re: Image Classification question

GordonSumerling — Sat, 25 May 2013 10:38:21 GMT

Mark,

I am working on a project at the moment and am using Zonal Stastics as a Table. I do this as I want to merge this data back to the features I used to produce the zone. The parcel ID is added to the output table which enables me to do a join back withe the original feature.

Cheers
Gordon

Re: Image Classification question

808707 — Tue, 28 May 2013 13:47:40 GMT

That's great Gordon. thanks for the advice.