A core requirement for all geospatial analysis is the ability to change the map projection of data in order to allow different layers to be open on the same map. Reprojection can be challenging, but QGIS makes it a snap of the fingers. Starting with this recipe, we will begin using the powerful QGIS Processing Toolbox. The Processing Toolbox wraps over 600 algorithms into a highly consistent API, available to Python and also as interactive tools. This toolbox was originally a third-party plugin named SEXTANTE, but is now a standard plugin distributed with QGIS.
As with many recipes in this chapter, we will use the SatImage raster available at https://geospatialpython.googlecode.com/files/SatImage.zip.
Place this raster in your /qgis_data/rasters
directory.