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Contributor
Posts: 59
Registered: ‎04-19-2016
Accepted Solution

Zonal Attribute Function in Spatial Modeler

Hi there,

 

This may be a silly question, but I am building a complex model and need help.

 

My model creates a shapefile of polygons (segments), and a raster image of meaningful values. What I'd like to do is populate the polygons with the MEAN statistical value of the raster image values, within a new column in the attribute table.

 

Manually I can go to the Raster Tab -> Thematic -> Zonal Attributes to do the said analysis, however I'd like to find out if there is an approach to do this in the Spatial Modeler (through different operators), so that I can complete this analysis as part of my complex model?

 

Please help!

 

Thanks in advance!

 

Best Regards

 

Jens

 

 

Highlighted
Technical Evangelist
Posts: 135
Registered: ‎07-04-2016

Re: Zonal Attribute Function in Spatial Modeler

Dear Jens,

 

Below you can find an illustration of how you can add the MEAN statistical value of the raster image values within a new column in the attribute table.

 

ERDAS IMAGINE 2016 model.jpg

 

Also attaching the model.

 

Hope this will help.

 

 

 

Kind Regards,

Marina

 

 

Kind Regards,
Marina Vardovska
Hexagon Geospatial Support
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Technical Evangelist
Posts: 961
Registered: ‎10-01-2015

Re: Zonal Attribute Function in Spatial Modeler

[ Edited ]

Excellent Model Marina.

 

This would be the equivalent using the new streaming features technology in ERDAS IMAGINE 2016:

 

Z_Mean.PNG

Ian Anderson
Chief Product Owner, Desktop Remote Sensing
Hexagon Geospatial
Highlighted
Contributor
Posts: 59
Registered: ‎04-19-2016

Re: Zonal Attribute Function in Spatial Modeler

Hi Marina and Ian,

 

Marina thanks for the awesome response, I have implemented the suggested model and it has really helped! So thank you!

 

Ian, I am glad you added the workflow (ERDAS 2016), because I was having trouble with the background row being included into the attribute transfer, so the "Remove Background Row" is exactly what I needed. Thanks.

 

My 2 cents, if the zones exist in raster as an input, the process is 10x faster inputing the raster zones than shapefile zones, and then adding the zonal attribute to the raster and then converting the raster to shapefile.

 

Also, the zonal mean attribute's accuracy is higher when analysing zonal raster to class raster, than zonal shapefile to class raster (which is understandable since the shapefile has to be converted to a raster cell before the zonal statistic processing can take place). This is only the case if the zones are available as raster and shapefile.

 

Anyways thanks guys, you are flippin awesome.

 

Cheers

 

Jens 

Highlighted
Regular Visitor
Posts: 1
Registered: ‎02-20-2017

Re: Zonal Attribute Function in Spatial Modeler

Did you manage to change "ZonalMean" to reflect the input image name and band? I am trying rename attributes but am getting the same old ZonalMean attribute name and green check marks in the modeller.