Wait the world isn't flat?! When did that happen?! ok… I'll google this whole "round earth" thing and get back to you. I'm still not sure if I believe you.
-Matt On Aug 8, 2013, at 11:57 PM, Clay Smalley <[email protected]> wrote: > Yes, there is some math. You're working with unprojected coordinates, and as > noted before, you'll need to project them. The simple explanation is that the > world is not flat, and a coordinate system that gives flatness to something > not-flat is going to look like shit. > > The projection used for most online mapping services is the Mercator > Projection. The biggest benefit of the Mercator Projection is that direction > is preserved (northeast will always point the same way no matter where you > are on the map). Because of this, 90-degree angles will stay 90-degree > angles. Try to find the math used to project unprojected coordinates to the > Mercator Projection. > > On Aug 8, 2013 6:40 PM, "Matthew Aidekman User" <[email protected]> > wrote: > Hi all, > > So, I'm getting some distorted displays and I'm hoping for some help. > As an example, this is how Times Square displays. (http://imgur.com/CQlIocE) > For those who haven't been to my amazing city, these blocks are all > rectangles in reality. A casual search has yielded some stuff about > projections but it's all been in regard to JOSM. I'm just downloading a JSON > file and processing it in Javascript with the JSON parser. > > All I'm doing so far is scaling the lon/lat coordinates to the size of the > display. I did a test and added the following code and as I expected it > does indeed display a right triangle on top of the distorted map. > > showLine(-73.790962, 42.252865,-73.791962, 42.253865); > showLine(-73.790962, 42.252865,-73.790962, 42.253865); > showLine(-73.790962, 42.253865,-73.791962, 42.253865); > > > Is there some extra math I'm supposed to employ to display lon/lat > coordinates beyond just scaling them to the dimensions of the display? > > Thanks in advance, > -Matt > > _______________________________________________ > newbies mailing list > [email protected] > http://lists.openstreetmap.org/listinfo/newbies > > _______________________________________________ > newbies mailing list > [email protected] > http://lists.openstreetmap.org/listinfo/newbies
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