AnsweredAssumed Answered

Surface volume tool results in NaN values

Question asked by devon.moore on Oct 22, 2019
Latest reply on Oct 23, 2019 by Dan_Patterson

I am attempting to calculate the volume of basin raster files with depth-related z values using the surface volume tool. This process has mostly been successful, however in some cases I receive the following error code under the volume field in the output table: 1.#QNAN. It should be noted that I am only receiving this error with specific data sources.

 

A bit of background on my intent:

All of my raster inputs originate from two types of georeferenced point datasets corresponding with depth and aquatic vegetation %biovolume values obtained from SONAR mapping of lakes*. To create the raster files, I interpolate the point data using the spline tool and clip to the appropriate spatial extent polygons. I then use raster calculator with the depth and %biovolume rasters as inputs to define a new 'depth to vegetation' (DtV) raster. The depth and DtV rasters then become the inputs in the surface volume tool. I subtract the DtV volume from the Depth volume to obtain a total vegetation volume for a given area.

 

*I perform the mapping myself and upload the SONAR files to an online service that QCs the data and produces a summary report. I can then export this processed data in the form of an XY table.

 

My understanding of the issue:

So far I haven't determined an underlying cause for the QNAN error, just that it occurs only in the Volume field of the output table and only with the DtV raster files (raster calculator output) of some of the older datasets. In my attempt to troubleshoot, I noticed that the depth and %biovolume points typically line up perfectly when imported into ArcMap as point shapefiles. However, in the older datasets, these points are not aligned--which is the only noticeable difference. I have attempted to remedy this potential issue by aligning the depth and %biovolume cells before performing the raster calculation, but this has not worked. 

 

I've tried looking into the root cause of the 1.#QNAN error, but haven't found anything conclusively tied to the surface volume tool. If anyone has any experience with this issue, please assist.

Thank you!

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