While PostgreSQL's, and therefore PostGIS's, structure is optimized to use vector data, we can also store raster data in a PostGIS database. The gains in this case are not as great as with vector data as QGIS will suffer a performance hit when it has to parse raster data from a PostGIS database instead of a file. On the other hand, PostGIS can query raster tables at various locations and, therefore, we can build expressions executing spatial analysis with mixed data. Furthermore, we might need to store rasters with vectors in a distributed system. One of the main pitfalls of adding raster data to a PostGIS database is that we cannot do it from QGIS. We have to use the command-line tool raster2pgsql.
Our first task is ...
