Many problems can be solved or decisions made on the basis of spatial queries, such as the number of households for a leaflet drop, length of pipes in need of inspection or minimum and maximum rainfall values. In this topic we examined the application of SQL to perform spatial queries and investigated how some simple geospatial metrics for length and area are calculated.

In this topic you have also been exposed to many spatial operations that a spatial analyst might want to use and may have been surprised / disappointed / relieved - delete as appropriate - to discover that a modern desktop GIS is likely to offer only a selection of these tools. We could say that a GIS analyst has to paint his/her picture from a pallette of limited colours!

Finally you found that the results of spatial analysis depend on several factors including the choice of operation and properties of the data such as the spatial data model and spatial scale.