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Re: What returns from distance function?
Posted by: Mike McCutcheon
Date: May 03, 2010 06:51AM

Thanks Bjorn. That's an excellent link you gave us (eg cross-track error) but ...

I (and presumably Onur and others) would like to know what unit of measure the result of distance() uses. Only when I/we know that can we work out how to convert that result into km or miles.

I have been using distance() successfully for:
- working out whether point X is within polygon Y (distance = 0)
- comparing *relative* distances (point X is further from poly Y than point Z is)

But now I need to calculate *actual* distances so I obviously need to know what unit of measure is used.

My points, lines and polygons are plotted in Google Earth, so my guess is that the unit of measure of results from distance() between these places is degrees of latitude, so we multiply by 60 to get nautical miles etc. Is that right ?

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