Last week I asked the list about the definition for the google maps
projection; thanks to all those who responded. But I'm still confused about
something: the projection is in meters, but Google maps seems to do
everything in lat-lng. Please forgive me if I'm being obtuse, but how and
why should I use srs 900913 instead of 4236?
Thanks again,
Steve
Stephen Crawford
Center for Environmental Informatics
The Pennsylvania State University
Stephen Crawford ha scritto:
Last week I asked the list about the definition for the google maps
projection; thanks to all those who responded. But I'm still confused about
something: the projection is in meters, but Google maps seems to do
everything in lat-lng. Please forgive me if I'm being obtuse, but how and
why should I use srs 900913 instead of 4236?
Simply put because that's the projection the gmaps tile do use. You see coords in lat/lon is just because the transformation is so easily reversed that javascript code can apply it as you move the mouse and
display geographic coordinates on the fly. If I remember properly
there are methods in the gmaps api allowing you to go from x/y on the screen to coordinates in meters to lat/lon.
Cheers
Andrea