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error with NDVIcalculator

  • 16 October 2019
  • 9 replies
  • 3 views

Userlevel 3
Badge +16

Hi,

 

As a non-expert in remote sensing, I would like to calculate the NDVI index from a CIR aerial photograph.

I came across this promising custom transformer on the hub ( NDVICalculator - @dmitribagh ) , but I always get this error message:

_RasterExpressionEvaluator_4 (RasterEvaluationFactory): Input 'B' is referenced in the expression list, but no 'B' feature was provided

I (think I) have an infrared and red band entering the transformer, and I also get a preview of the output of the transformer, but I can't write the result as the translation stops with the fatal error above ...

 

What could I do wrong (as a FME newbie...)? My workbench with a sample of the aerial photograph attached

 

Any help much appreciated!

 

 

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Best answer by becchr 17 October 2019, 09:33

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9 replies

Badge +10

Your workspace runs fine for me... (2019.0)

Userlevel 3
Badge +16

Thank you for testing!

 

I get the error when running on FME(R) 2019.1.1.0 (20190801 - Build 19617 - WIN64), logfile with error: NDVI_Calculator_Error.txt

 

I did not think of testing it on another version, so I only just found out the workspace runs fine indeed on FME(R) 2018.1.0.3 (20180926 - Build 18552 - WIN64), guess there's something wrong with my latest FME-version...

Badge +16

Thank you for testing!

 

I get the error when running on FME(R) 2019.1.1.0 (20190801 - Build 19617 - WIN64), logfile with error: NDVI_Calculator_Error.txt

 

I did not think of testing it on another version, so I only just found out the workspace runs fine indeed on FME(R) 2018.1.0.3 (20180926 - Build 18552 - WIN64), guess there's something wrong with my latest FME-version...

Hi, I can confirm the same behavior, 2019.1 errors and 2018 works just fine.

I would suggest contacting Safe about this.

Badge +10

Thank you for testing!

 

I get the error when running on FME(R) 2019.1.1.0 (20190801 - Build 19617 - WIN64), logfile with error: NDVI_Calculator_Error.txt

 

I did not think of testing it on another version, so I only just found out the workspace runs fine indeed on FME(R) 2018.1.0.3 (20180926 - Build 18552 - WIN64), guess there's something wrong with my latest FME-version...

It's odd because if the NDVI option is selected _RasterExpressionEvaluator_4 shouldn't be involved at all. If you disable it in the custom transformer the process will run without error in 2019.1

 

Userlevel 3
Badge +16

It's odd because if the NDVI option is selected _RasterExpressionEvaluator_4 shouldn't be involved at all. If you disable it in the custom transformer the process will run without error in 2019.1

 

Wow, my introduction to the wonderful world of editing custom transformers!

Thank you both for testing and helping, i'll let it now at the HUB-page of the transformer too

Userlevel 4
Badge +25

Wow, my introduction to the wonderful world of editing custom transformers!

Thank you both for testing and helping, i'll let it now at the HUB-page of the transformer too

I'll have a look at the problem and see if I can get it resolved. Thanks for reporting this.

Userlevel 4
Badge +25

Interestingly, I tried this on FME2019.2 and it all works fine. If you have the time/patience to give it a go, perhaps you can see if it works for you too? You could get this as a beta from safe.com/downloads.

I'm going to carry on testing, to install the same build as you and find out what the issue is, but it currently looks like a temporary glitch that has been resolved already.

Userlevel 4
Badge +25

Interestingly, I tried this on FME2019.2 and it all works fine. If you have the time/patience to give it a go, perhaps you can see if it works for you too? You could get this as a beta from safe.com/downloads.

I'm going to carry on testing, to install the same build as you and find out what the issue is, but it currently looks like a temporary glitch that has been resolved already.

It looks to us like this was fixed in build 19624 (just a few builds after your version). If you download the latest 2019.1 (2019.1.3, build 19642). The fix didn't make it to the whatsnew file (not everything does), but we think it is related to:

INTERNAL: Prevented errors in some groupby factories when no features were given <ms><kjw>

So I'm going to give that build a try, but - even though I don't know when it was introduced - I'm 99% confident that this issue is fixed now.

Userlevel 3
Badge +16

Interestingly, I tried this on FME2019.2 and it all works fine. If you have the time/patience to give it a go, perhaps you can see if it works for you too? You could get this as a beta from safe.com/downloads.

I'm going to carry on testing, to install the same build as you and find out what the issue is, but it currently looks like a temporary glitch that has been resolved already.

Thank you very much for your effort, I've downloaded the latest 2019.1 (build 19642) and all works fine indeed.

Seems I just was unlucky with the build I was using, glad there's a happy end!

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