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Posts: 27
Registered: ‎03-28-2019
Accepted Solution

Empty rows in accuracy assessment



Im trying to carry out an unsupervised classification, then run the accuracy assessment. I'm getting lots of empty space in the error matrix and kappa output file - so not sure what to do to remove it as doesnt seem to be in any videos i have watched. Ive looked at other posts and tutorials but doesnt seem to be the same issue that im having and recoded all empty rows (as newrow 15 for example) didnt seem to do anything as the empty rows still remain.


I'm using Erdas Imagine 2018, 8 bit landsat 5 subset, unsupervised, kmeans, 15 clusters, classify zeros, grayscale output


When i look at Thematic Recode (following fixes other posts) it has 255 rows in the table, but all are empty from row 15 down. The accuracy assessment outputs however seem to have all of those rows included. 





I've attached a sample output txt file - added 50 random points and added some random ref values, so ignore the poor scores. I can get higher scores, just made this one quickly for the post as not sure how to get rid of those empty entries.  




Technical Evangelist
Posts: 944
Registered: ‎10-01-2015

Re: Empty rows in accuracy assessment

Hi Conor,


Obviously it shouldn't be doing that - can you please log a Support Ticket.


But I can suggest a workaround:


  1. Display your classified image in a 2D View
  2. Invoke Accuracy Assessment tool and open the classified image
  3. Generate whatever points you want to use
  4. Fill in the Reference values
  5. File > Save Table
  6. Close the Accuracy Assessment tool
  7. Invoke Accuracy Assessment tool and open the classified image (which will pre-load all the points you configured)
  8. Report > Accuracy Report
  9. The resulting report should not have all the empty (histogram = 0) rows in it

Hope that helps!




Ian Anderson
Chief Product Owner, Desktop Remote Sensing
Hexagon Geospatial
Posts: 27
Registered: ‎03-28-2019

Re: Empty rows in accuracy assessment

The workaround did the job, thanks. Cant seem to log a support ticket as it wont recognsie my username/password for some reason, despite letting me login here. 

Technical Evangelist
Posts: 640
Registered: ‎02-02-2016

Re: Empty rows in accuracy assessment

Hi Conor,


The Support Portal isn’t available to all users. In your case you should contact your Hexagon Geospatial partner who supplied your ERDAS IMAGINE license and they can open a support ticket on your behalf. If you can’t recall the contact information for your Hexagon Geospatial partner you can use the webpage linked below to find our partners in your region.


Hexagon Geospatial Partners


Kind regards,


Stephen Bent
Hexagon Geospatial Support