Zonal Histogram By Polygon Incorrect.

KarlSchrantz · ‎10-03-2012

Hello,

I am using a 30meter raster of land use data that I have split into 4 classes. I wish to count the number of cells within each class that reside within census tracts and counties as zones.

When I get the table from the Zonal Histogram at the county level It tells me that class 3 has 837 cells, but when I use the census tracts as the zone, each zone has over 1000 cells.

I am at my wits end and I have been trying to solve this for the better part of 3 days now.

I am using arc 10 sp4.

Is there a work around for this?

Thanks

KarlSchrantz · ‎10-04-2012

Hello,

I am using a 30meter raster of land use data that I have split into 4 classes. I wish to count the number of cells within each class that reside within census tracts and counties as zones.

When I get the table from the Zonal Histogram at the county level It tells me that class 3 has 837 cells, but when I use the census tracts as the zone, each zone has over 1000 cells.

I am at my wits end and I have been trying to solve this for the better part of 3 days now.

I am using arc 10 sp4.

Is there a work around for this?

Thanks

I tried exporting the tract polygons to a raster of the same cell size and used a snap raster in the environment settings. Still same result if I use all of the tracts even in raster form it is not correct. If i just have one tract raster if works fine. WHY IS IT DOING THIS?!?!

KarlCox · ‎11-01-2012

I have also been having trouble with this. I have a raster with about 20 classes in it that I am trying to summarize for a series of overlying polygons. I converted the polygons to rasters and tried the Zonal Histogram but it is only returning results for one class of the 20 (the middle one if that helps any). I worked around this the other day by creating single class rasters and then running Zonal Statistics 20 times and re-tabulating all the data in excel....a tedious process at best.

Does anybody else have this issue? I have tried adjusting any possible environment settings, ensuring they are in the same projection and only having the two layers in the project, all to no avail.

Suggestions greatly appreciated.

Karl Cox

AndrewBrown1 · ‎02-27-2013

Same problem. I'm running 10.1 SP1.

EveLundsten · ‎02-28-2013

I've had the same problem with 10.0 SP1. It turned out the histogram analysis (I used the little icon next to Spatial Analyst toolbar) was dependent on the scale that the grid is displayed at...I called ESRI support (we pay for it), and they had me uninstall SP1. Problem solved. Now with 10.1 the problem is back. ArgggH!

EveLundsten · ‎02-28-2013

I just spoke to ESRI again and the bug wasn't fixed. We have to go back to Arc GIS 10.0 SP3 (I was wrong in my post above, they had me uninstall SP4 previously to fix my problem). So if you want an accurate histogram of your raster you have to go back to 10.0 SP3. Argh!

AndrewBrown1 · ‎03-01-2013

Wow...

So, ESRI told you to uninstall 10.1 completely, re-install 10.0 and then patch it to SP3? Once you get the tool to work, then you'd have to uninstall everything and re-install 10.1 and patch to SP1. That is a JOKE!

That can take over an hour with the way the ArcGIS installer works. I hope they're paying for time lost on your projects.

I also have a call in to ESRI, but their analysts never called me back. So much for customer service.

EveLundsten · ‎03-01-2013

I was planning on installing on an older laptop. Their recommendation was to suck it up and not use any histogram analysis! And they recommended I go to the ideas website to give feedback directly to the developers. Maybe some of you can too and we can convince them to do something.
Here is what they said:
"As discussed please use our ideas website to post your ideas and suggestions.

The Ideas website is a collaborative brainstorming environment that allows users to submit, discuss, and even vote on Esri products and enhancements. Esri created this community site to allow our customers to get more involved by:
o Posting new ideas
o Voting on other's ideas
o Commenting/Refining ideas
o Receiving updates about Ideas under consideration
o Viewing Ideas that are implemented
o Emailing/ Tweeting about ideas
o Sharing Ideas using social networks

http://ideas.arcgis.com/ideaHome?c=09a300000004xET
"

PavanYadav · ‎03-01-2013

Greetings!
This is Pavan with Esri User Advocacy Group. I would like to see if I can help you with the different issues you have.

Karl Schrantz and karlCox3, we understand that you are using the Zonal Histogram (geoeprocessing) tool and experiencing unexpected behavior. It could be possible you are encountering a possible software defect that we are not aware of. Could you please contact Technical Support so we can work with you to get a reproducible case and/or troubleshoot your issue? Please visit this link: http://support.esri.com/phoneSupport#us for contact information. If you don�??t have a maintenance contract, please email me at pyadav @ esri DOT com. So that I can email you back to get more information.

Eve, The interactive Histogram tool issue was reported as an usability issue and the analysts shared this documentation with you. The documentation explicitly states that the behavior in the question is applicable from ArcGIS 10.0 Service Pack 4 onwards only and the interactive contour and histogram tools (not the Zonal Histogram tool) operate on the data within the extent of your ArcMap window and at the screen resolution. The documentation also discusses why we made this change. Service packs provide you maintenance fixes, performance improvements, software enhancements, and translation updates; all of which will improve the quality of your ArcGIS system. So we would not recommend you to roll back to 10.0 SP3. I understand that you would like to create histogram using the interactive Histogram tool, based on the user defined classes on the value raster in the Table of Content (TOC) of ArcMap . I would like to share this solution �?? please create a constant raster using the Create Constant Raster tool (in the environment settings, please specify you value raster in the Extent, and Snap Raster and Cell Size parameters). Now, open the Zonal Histogram (geoprocessing) tool > specify the constant raster in the Input raster or feature zone data parameter, Input value raster = your values raster from the TOC, and Output graph name. The output graph will be generated based on the input raster. I�??ll also talk to the analyst and show him the workflow, just in case if you need him to walk you through.

Andrew Brown, Can you please give me your support incident number so that I can talk to the appropriate team and have them an analyst contact you ASAP?

Best regards,
Pavan

Pavan Yadav | Development Technical Lead
User Advocacy Group | Support Services
Esri | 380 New York Street | Redlands, CA 92373 | USA