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Showing posts from December, 2008

Translating Coordinates

Of all the GIS questions I field, coordinate system related questions are the most frequent. The following is typical:
I got a shape file of land parcels from Bonneville Co. and am trying to overlay that onto the County NAIP imagery. For some reason, when I have the same coordinate system and datum assigned to all layers, the NAIP and shape files are projecting at different scales and not even coming close to lining up. I’ve tried everything in my limited arsenal. If you have any idea of what’s going on, please let me know.

The problem here is not a lack of understanding of the software (or grammar), but misunderstanding concepts behind assigning and translating a coordinate systems.

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I've found language translation to be the most accurate analogy for making sense of coordinate systems in ArcGIS.

Suppose you're traveling on a ferry in the Baltic Sea (why not?). A frazzled tourist is running from person to person animatedly asking a question. Fortunately, you have…