Spherical Mercator — OpenLayers. This document describes the Spherical Mercator projection, what it is, and when you should use it.
It includes some background information, demonstration of using the code with just a commercial layer, and how to add a WMS over the top of that layer, and how to reproject coordinates within OpenLayers so that you can reproject coordinates inside of OpenLayers. It is expected that readers of this tutorial will have a basic understanding of reprojection and a basic understanding of OpenLayers. What is Spherical Mercator? Spherical Mercator is a de facto term used inside the OpenLayers community – and also the other existing Open Source GIS community – to describe the projection used by Google Maps, Microsoft Virtual Earth, Yahoo Maps, and other commercial API providers. OGR: OGR Simple Feature Library. The OGR Simple Features Library is a C++ open source library (and commandline tools) providing read (and sometimes write) access to a variety of vector file formats including ESRI Shapefiles, S-57, SDTS, PostGIS, Oracle Spatial, and Mapinfo mid/mif and TAB formats.
OGR is a part of the GDAL library. Resources Download Ready to Use Executables. Open Source GIS.