Error when using collocation to compare 2 NDVI images

When using the collocation tool to compare two NDVI images it returns this expression: Undefined symbol ‘ndvi_flags_M.NDVI_ARITHMETIC_M’

Could anybody help with this error?

Hi @Abigail_Danks,

Welcome to the forum!

Could you confirm me your pipeline?
It should look like:

Product1 => NDVI \\
Product2 => NDVI //

Is it right? could you give me the names of two products you are using so I can try myself?


I get the same error message but only after I try a band maths operation after colocating (successfully) an NDVI and a SAVI processing from a single S2 MSI image. I can colocate two supervised classification files and undertake a band math operation fine - and band maths works with bands inside the MSI image - but it doesn’t work with the NDVI/SAVI images… Michael Hewson

you can use the stack tool as an alternative as described here: Band Math Expression Error in Collocate

Many thanks - yes that works MH