Whats going on: I am working with postGIS and spatial datas. I am having trouble to fully understand the
Example query: In which town is point P located?
My understanding so far is:
Each polygon has a
boundingBox has an idex. These
boundingBoxes are then merged into another larger
boundingBox which also has an idex. Continuing the process creates the
R-tree. With the help of the
R-tree the query is much faster. But ...
My question is at what point are these indexes created?
Does the R-tree exists per se?
Or is the
R-tree created on the run time when I start a query?