Maptitude - http://research.umbc.edu/~roswell/maptitude.html
I have a large polygon layer (22,000 polys) and a large line layer (135,000
lines). I need to transfer an attribute from the line layer (traffic
counts) to the polygon layer (block groups). So, I use the OVERLAY tool to
add this attribute to the polygon layer. I select the appropriate summation
method (sum) and start the tool. It runs for a long time (10-15 minutes) on
my computer and then ends with this error message:
ColumnAggregate returned an error
Reference Info: aggr,178,1
Does anyone have any insight as to what this error message means? I suspect
it results from bad or twisted topology in the polygon file, although it was
successfully created from a shape file with the "Eliminate duplicate lines"
checkbox checked. I doubt it's a divide by zero problem, as I am only
summing. After clicking OK on this error message box the OVERLAY tool
terminates. This leads to my main point. I think it would be much better
if when OVERLAY hits a record it cannot perform summation for, it set the
sum field to NULL for that record and then proceeded to the next record. At
the end, the tool could pop up a dialog stating that summation could not be
performed at records xx and xx. Instead, after the error, the user is left
with nothing, and in my case has wasted 10-15 minutes unproductively. Is
there some internal program logic that prevents this that I don't see?
After all, you're basically just adding a field to a table. It's not like
creating a geographical file where an error in one node would create a
corrupted or inaccurate file. Any comments on this?
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