Organizing the QGIS Python libraries

Now that we can understand the C++-oriented documentation, let's see how the PyQGIS libraries are structured. All of the PyQGIS libraries are organized under a package named qgis. You wouldn't normally import qgis directly, however, as all the interesting libraries are subpackages within this main package; here are the five packages that make up the PyQGIS library:

qgis.core	This provides access to the core GIS functionality used throughout QGIS.
qgis.gui	This defines a range of GUI widgets that you can include in your own programs.
qgis.analysis	This provides spatial analysis tools to analyze vector and raster format data.
qgis.networkanalysis	This provides tools to build and analyze topologies.
qgis.utils	This implements miscellaneous functions that allow you to work with the QGIS application using Python.

The first two packages (qgis.core and qgis.gui) implement the most important parts of the PyQGIS library, and it&apos...