[OSM-newbies] Squashed Display (Not JOSM)

[Matthew Aidekman User]

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 <claysmalley at gmail.com> 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" <matthewaudio at gmail.com> 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
> 
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