bbq

Beta 2; Raster to Feature - unwound polygons in File GDB

Discussion created by bbq on Feb 9, 2010
Latest reply on Feb 12, 2010 by bbq
I've been using Beta 2 Spatial Analyst for some hydrology problems.  One of the steps I need is to offer a generalized delineation of local depressions (filled areas in the hydro-DEM) for a consultant.

For long years I've found useful the raster-to-feature conversion in Spatial Analyst, and been grinning and bearing it when it only produced Shapefile output.  Now at Beta 2, I'm pleased to direct my output to a file GDB, but have had the experience of that process failing <<and producing some intriguing abstract art>> with polygons unwound: sequences that trace boundaries of isolated polygons are linked with an edge to the next polygon in a row.

Today, I simplified the shapes with one more cycle of morphology opening (ERDAS Imagine morphological erode-then-dilate) and, following tradition, deliberately selected Shapefile output.  The process completed in about 90 seconds, and successfully.  The results are posted for post-mortem

direct_to_fgdb_failed_pg   has 21516 polygons, with many unwound
Novato_erode5355_dilate7_from_Shapefile_pg has 7021 polygons

These aren't exactly comparable, as the second is clearly more simplified---but I'm working on the paid task here and trying to share the experience in forum as best I am able to.  The FGDB is 10MB and so I'm posting the link rather than attaching:

http://bit.ly/csEIR0 

-=Brian

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