-------- Original Message --------
Subject:        Re: Lat/long in Google maps
Date:   Wed, 08 Aug 2007 16:29:49 -0400
From:   Zachary Christman <[log in to unmask]>
Organization:   Clark University Graduate School of Geography
To:     Maps, Air Photo & Geospatial Systems Forum <[log in to unmask]>




Maps-L wrote:
> FYI, I think that the Google Earth is using the
>> Platte Carre projection.
>
> Nope, good ol' Mercator. Hence it is conformal at all scales...
> Actually an application where it makes a lot of sense, since it is
> mostly used at large scales.
Just an update, from the horse's mouth (both answers are "correct";
Plate Carree for display and Mercator for data storage and importing):

http://earth.google.com/userguide/v4/ug_importdata.html
"A Note About Projections and Datums

Google Earth uses Simple Cylindrical projection with a WGS84 datum for
its imagery base.

Google Earth uses Simple Cylindrical projection with a WGS84 datum for
its imagery base

   1. Simple Cylindrical (Plate Carree) Projection
   2. Google Earth Image Base

Typically, the data you import into the Google Earth application is
created with a specific geographic coordinate system, such as a
Universal Transverse Mercator (UTM) projection and a NAD27 datum (North
American Datum of 1927). Each geographic coordinate system may assign
slightly different coordinates to the same location on the earth. When
you import data into Google Earth, your data is interpreted according to
the Google Earth coordinate system.

In the majority of cases, reprojection works as expected. In some
situations, the transformation might not work properly. In that case,
you can use a third-party tool to transform your data from its original
coordinate system into the one used by Google Earth.

The rest of this section provides a brief overview of map projections
and datums."