[josm-dev] Meters to Pixels

[Alan Mintz]

At 2010-10-28 06:32, Tobias Wendorff wrote:
>Am Do, 28.10.2010, 12:04 schrieb Irene Pucci:
> > There is a method that converts meters in pixels?

In the Windows environment anyway, there are API calls that are used to 
deal with screen, print, etc. metrics.

The easiest way to find out, though, is to experiment. For me, in JOSM, the 
zoom level in meters corresponds to 100 pixels. I can confirm this by 
drawing a segment the length of the scale bar and confirming its size as 
100 pels by capturing the image and examining it with a graphic editor. You 
can see in the measurement dialog* that the way is equal in length to the 
current scale. You can also calculate the distance between the endpoints 
using any of the standard geoscience tools and see that it concurs within 
reason* for short distances. There are issues of arc length vs. projected 
length vs. whatever for longer distances.


*Note: Both the measurement dialog and the status line in JOSM are slightly 
"wrong" (though different from each other), as reported in 
http://josm.openstreetmap.de/ticket/4849. Also note in that report that the 
area is very wrong away from the equator.

--
Alan Mintz <Alan_Mintz+OSM at Earthlink.net>