I am playing around with a map of bike lanes (so, lines) and trying to calculate the total number of miles of lane in each of a couple of regions. But I'm not even sure how to use
ST_Length to calculate miles. I'm getting values of .001 and I don't even know what that means.
The documentation: http://postgis.org/docs/ST_Length.html is confusing to me -- I think this is supposed to be giving me meters, but I'm not entirely sure, and the segments tend to be one or tow blocks long, so ... more than .001 meters.
How can I use
ST_Length to calculate miles?