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How to deal with 'No Data' Values in Topographic Wetness Index

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03-16-2016 02:16 AM
NasirHameed
Occasional Contributor

I have derived Topographic Wetness Index (TWI)/CTI with ArcGIS 10.3 using 30m DEM resolution. Earlier, it was propagating negative values which were mainly confined to ridges. I have restructured the 'Raster Calculator' expression as below and got rid of negative values.

Ln(("Flow_acc"+ 1 ) * 900/"Tan_SlopeRad")

The below process diagram would acquaint you about steps I have taken to arrive at the positive integer values.

PFD.jpg

and the resultant image clearly indicates values having 'No Data'. These values are mainly confined to Zero Degree Slope within River.

Results.jpg

Earlier, I uploaded this query on the following link but no response has been made so far:-

arcgis desktop - No Data Values in TWI Raster - Geographic Information Systems Stack Exchange

Now, How would I deal with values having ''No Data'???

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10 Replies
DanPatterson_Retired
MVP Emeritus

Looks good!

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