Adding a world file to a map image

Exporting a map as an image removes all of its spatial information. However, you can create an external text file called a world file, which provides the georeferencing information for the raster image, so that it can be used by GIS software, including QGIS, as a raster layer. In this recipe, we'll export a map composition as an image and create a world file with it.

Getting ready

You will need to download the zipped shapefile from https://geospatialpython.googlecode.com/svn/Mississippi.zip and extract it to your qgis_data directory, to a subdirectory named ms.

In addition to the shapefile, you will also need the MapComposer class to simplify the code needed to add this one element. If you have not already used it in a previous recipe, you can download it from https://geospatialpython.googlecode.com/svn/MapComposer.py.

This file must be accessible from the QGIS Python console; for this, you need to ensure that it is in the python path directory. Place...