The Paleomap Project, developed by Dr. Chris Scotese, is designed to display the evolving Earth as tectonic plates have shifted through time. This project is recognized worldwide as a resource for students and teachers of Earth history. A nice overview can be found here. (Oh, and did you catch the reference to Chris and his work on Very Spatial Episode 21?)
Well, I have been helping him to integrate the Plate Tracker program that Chris wrote in VB6 into ArcMap. Put quite a bit of effort into this, but as always with such efforts, I sure learned a lot. The program allows users to view how different polygons on the Earth's surface would look in a given time period of Earth's history (measured in millions of years).
I will not post the code, but here is the logic of the script:
- Convert polygon to table of XY coords
- Launch Plate Tracker (VB6 executable) which shifts the coords according to the time period selected
- Python once again takes over and converts the shifted coords into a new polygon feature class
Works like a charm. The two biggest hurdles that I had to overcome were (1) handling multipart and donut (inner circles) polygons, and (2) Ensuring that the resulting polygon contained the same attributes as the original file. Solving these hurdles taught me a lot about lists and sublists in Python. Special thanks to all the folks over at ArcView-L for helping me out with the donut polygon problems. This is a great listserv where folks will definitely get back to you.