PostGIS Cookbook - Second Edition

Getting ready

We will start by loading our data. Our data is the address records from Cuyahoga County, Ohio, USA:

shp2pgsql -s 3734 -d -i -I -W LATIN1 -g the_geom CUY_ADDRESS_POINTS chp04.knn_addresses | psql -U me -d postgis_cookbook  

As this dataset may take a while to load, you can alternatively load a subset:

shp2pgsql -s 3734 -d -i -I -W LATIN1 -g the_geom CUY_ADDRESS_POINTS_subset chp04.knn_addresses | psql -U me -d postgis_cookbook  

We specified the -I flag in order to request that a spatial index be created upon the import of this data.

Let us start by seeing how many records we are dealing with:

SELECT COUNT(*) FROM chp04.knn_addresses; 
--484958

We have, in this address table, almost half a million address records, which is not an ...