Fill tool taking forever to complete after processing is done.

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05-12-2012 04:37 AM
MarcoBoeringa
MVP Regular Contributor
Hi all,

Has anyone else noticed this: when I run the Fill tool to remove spurious sinks in my raster DEM, ArcMap and the Fill tool seem at first to be working quite fast, 0-100% in limited time, in consecutive iterative runs to properly fill the sinks. However, after seeing the 0-100% progress bar fully finish 3x times or so (or as much as the iterative process of filling needs), ArcMap than fails to add the created DEM. Instead, it starts pounding away like crazy on the harddisk, in a kind of activity you really do not want on a hard drive but only in RAM or on a SSD as it will wear out a hard disk fast, and only adds the final result a very long time after the progress bar of the Fill tool disappeared. So it does finish, but maybe an hour or so after the five minutes Fill tool processing as displayed by the progress bar. I noticed the final processing of the raster takes place in your Windows users accounts "Temp" directory, as I can see activity going on there related to ArcMap.

I am fully aware that the fill process is an intensive one, but this seems wrong. It seems like ArcGIS needs an excessive amount of time to write the final result. I realize the fill tool needs to update the existing grid in specific locations, and I begin to wonder if that is the issue??: ArcMap trying to write a raster in a kind of extremely inefficient database SQL Update statement, replacing records in a file geodatabase raster table instead of just dumping a whole new raster table in the file geodatabase that is my final destination location for the result...

Anyone else notice the same issues with the Fill tool?

Marco
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MarcoBoeringa
MVP Regular Contributor
OK, I now discovered more or less what and where is actually going on. While ArcMap only shows a progress bar for a few minutes, the unaccounted time afterwards is spend writing classic ESRI grid format files in the Windows user profile's Temp directory. I can see ESRI grid files being build up (file size increases) in cryptically named subfolders. Seems the processing needed for a fill are far from over when ArcMap stops showing progress. Frustrating.

It is still unclear exactly what is going on. I know the Help states Fill is the equivalent of a number of tools combined. "The Fill tool uses the equivalents of several tools, such as Focal Flow, Flow Direction, Sink, Watershed, and Zonal Fill, to locate and fill sinks.", so I wonder if ArcMap is just combining the outputs of these processes, or is really "filling up" / replacing sinks with hydrologically corrected DEM values.

Whatever, I am glad it is now doing it on an external SSD, and not my harddisk, because it is literally writing Gigabytes of grid data on end to the Temp and subsequently removing files again.
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