Subtitled: Why error messages are good. Came up with another error while running TopoToRaster but this time ArcGIS gave an error message that led to a solution. Turned out all my contour lines had an elevation of 16 which TopoToRaster did not like. I had intended to increase the elevation and inadvertently set them all to sixteen. I had saved the previous values before editing so it turned out to be a simple fix and I didn’t have to spend a day trying figure out what was wrong.

In running an automated process, I had a TopoToRaster repeatedly fail on me. The only input theme was a contour theme. The process ran fine when I used the envelope of the contour theme as the output extent but when I changed it to the envelope of a polygon theme, it would bomb. The polygon’s envelope was smaller than the contour theme. ArcCatalog would bomb out without presenting any sort of useful message.