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- -- The city engineer needs to find out that a lot is
- -- within the footprint of the buiding. There are two tables
- -- created here to get the building footprints and the lots.
- -- The building footprints are stored in the buildingfootprints
- -- table created with the following CREATE TABLE statement.
- CREATE TABLE buildingfootprints (building_id integer,
- lot_id integer,
- footprint ST_MultiPolygon);
- -- Here is the creation of the lots
- CREATE TABLE lots (lot_id integer,
- lot ST_MultiPolygon);
- INSERT INTO buildingfootprints VALUES(
- 506, 1010,
- ST_MPolyFromText('multipolygon (((7.0 45.0,15.0 45.0,15.0 51.0,18.0 51.0,18.0 54.0,8.0 54.0,8.0 51.0,7.0 51.0,7.0 45.0)))',1000)
- );
- INSERT INTO buildingfootprints VALUES(
- 543, 2930,
- ST_MPolyFromText('multipolygon (((26.0 55.0,38.0 55.0,38.0 48.0,34.0 48.0,34.0 50.0,26.0 50.0,26.0 55.0)))',1000)
- );
- INSERT INTO buildingfootprints VALUES(
- 1208, 203,
- ST_MPolyFromText('multipolygon (((8.0 39.0,12.0 39.0,12.0 33.0,17.0 33.0,17.0 22.0,8.0 22.0,8.0 39.0)))',1000)
- );
- INSERT INTO buildingfootprints VALUES(
- 178, 5192,
- ST_MPolyFromText('multipolygon (((26.0 33.0,38.0 33.0,38.0 24.0,33.0 24.0,33.0 27.0,26.0 27.0,26.0 33.0)))',1000)
- );
- INSERT INTO lots VALUES(
- 1010,
- ST_MPolyFromText('multipolygon (((2 57,21.5 57,21.5 38,2 38,2 57)))',1000)
- );
- INSERT INTO lots VALUES(
- 2930,
- ST_MPolyFromText('multipolygon (((21.5 57,40 57,40 38,21.5 38,21.5 57)))',1000)
- );
- INSERT INTO lots VALUES(
- 203,
- ST_MPolyFromText('multipolygon (((21.5 38,40 38,40 20,21.5 20,21.5 38)))',1000)
- );
- INSERT INTO lots VALUES(
- 5192,
- ST_MPolyFromText('multipolygon (((2 20,2 38,21.5 38,21.5 20,2 20)))',1000)
- );
- -- The city engineer first selects the buildings that are not completely
- -- contained within one lot.
- SELECT building_id
- FROM buildingfootprints, lots
- WHERE NOT ST_Contains(lot,footprint);
- -- The city engineer realizes that although the first query will provide
- -- her with a list of all building IDs that have footprints outside of a
- -- lot polygon, it won't tell her if the rest have the correct lot_id
- -- assigned to them. This second query performs a data integrity check
- -- on the lot_id column of the buildingfootprints table.
- SELECT bf.building_id, bf.lot_id, lots.lot_id
- FROM buildingfootprints bf, lots
- WHERE NOT ST_Contains(lot,footprint)
- AND lots.lot_id <> bf.lot_id;
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