Idrisi to MS Word

You can make maps in Idrisi. Well, sort of. Almost. Map-like graphics… okay, you cannot make a proper map in Idrisi. What you can do, is have a very rudimentary map display with a grid and marginalia. This post is about how to bring it into Word. Continue reading “Idrisi to MS Word”

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Multiple Ring Buffer in ArcGIS 10.0

So my colleague has a feature class with 658 polygons, and runs the Multiple Ring Buffers tool in ArcGIS 10.0 on it. Not a big deal you might think. However, processing takes forever, a after 6 hours we give up and cancel.

So what is going on? I run some tests with subsets of the original feature class:

  • using only the  31 largest features: runtime 0.5 minutes
  • using only the  79 largest features: runtime1.5 minutes
  • using only the  199 largest features: runtime7 minutes
  • using only the  340 largest features: runtime already 40 minutes and counting…

It turns out the Multiple Ring Buffers tool is very sensitive to the number of features.Workaround: for large numbers of features I use the standard buffer tool, and if I need doughnut type polygons I then use Union or Erase, as required.