Hi @dallas2011 

I don’t believe there is a specific transformer that will calculate IRI. 

If you know the formula however, you can use either the AttributeManager or AttributeCreator transformer to create a new attribute and enter the formula to set the value. This can be done by selecting the Arithmetic Editor from the Value column. 

I hope this helps! 

Crystal 

Dear Crystal,

thanks your answer I appreciate it 

Maybe you know the formula how to write into attribute creator? 
thanks advice 

Hi @dallas2011 

I just want to confirm by IRI you mean the international roughness index? 

While I don’t know the formula, this link might help https://community.esri.com/t5/water-resources-blog/terrain-ruggedness-index-tri-and-vector-ruggedness/ba-p/884340 

In terms of writing the formula in the AttributeManager this link might help you out with setting up the Arithmetic Editor in the value column (under number 10). 

https://support.safe.com/s/article/the-attributemanager-transformer 

Crystal