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change place node expansion for large area table

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So far we've used a buffer around a place node to define its
potential address reach. This had two problems: the buffer was
so large that addresses often contain false positives and the
buffer is really distorted when getting closer to the poles.

Change the buffer here to draw a bounndig box at a certain
distance in meter. This means that we always use the same
box everywhere on the planet and can make the extent much
smaller. Using a box has the advantage that it is much faster
to figure out if a point is within the box.
This commit is contained in:
Sarah Hoffmann
2020-05-06 22:22:24 +02:00
parent 5abec720d8
commit a5697c5279
2 changed files with 41 additions and 43 deletions
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62
sql/functions/utils.sql
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@@ -272,6 +272,25 @@ END;
$$
LANGUAGE plpgsql;
CREATE OR REPLACE FUNCTION near_feature_rank_distance(rank_search INTEGER)
RETURNS FLOAT
AS $$
BEGIN
IF rank_search <= 16 THEN -- city
RETURN 7500;
ELSIF rank_search <= 18 THEN -- town
RETURN 4000;
ELSIF rank_search <= 19 THEN -- village
RETURN 2000;
ELSIF rank_search <= 20 THEN -- hamlet
RETURN 1000;
END IF;
RETURN 500;
END;
$$
LANGUAGE plpgsql IMMUTABLE;
CREATE OR REPLACE FUNCTION add_location(place_id BIGINT, country_code varchar(2),
partition INTEGER, keywords INTEGER[],
@@ -282,18 +301,11 @@ CREATE OR REPLACE FUNCTION add_location(place_id BIGINT, country_code varchar(2)
DECLARE
locationid INTEGER;
centroid GEOMETRY;
diameter FLOAT;
x BOOLEAN;
splitGeom RECORD;
radius FLOAT;
secgeo GEOMETRY;
postcode TEXT;
BEGIN
IF rank_search > 25 THEN
RAISE EXCEPTION 'Adding location with rank > 25 (% rank %)', place_id, rank_search;
END IF;
x := deleteLocationArea(partition, place_id, rank_search);
PERFORM deleteLocationArea(partition, place_id, rank_search);
-- add postcode only if it contains a single entry, i.e. ignore postcode lists
postcode := NULL;
@@ -305,32 +317,18 @@ BEGIN
centroid := ST_Centroid(geometry);
FOR secgeo IN select split_geometry(geometry) AS geom LOOP
x := insertLocationAreaLarge(partition, place_id, country_code, keywords, rank_search, rank_address, false, postcode, centroid, secgeo);
PERFORM insertLocationAreaLarge(partition, place_id, country_code, keywords, rank_search, rank_address, false, postcode, centroid, secgeo);
END LOOP;
ELSE
ELSEIF ST_GeometryType(geometry) = 'ST_Point' THEN
radius := near_feature_rank_distance(rank_search);
--DEBUG: RAISE WARNING 'adding % diameter %', place_id, diameter;
diameter := 0.02;
IF rank_address = 0 THEN
diameter := 0.02;
ELSEIF rank_search <= 14 THEN
diameter := 1.2;
ELSEIF rank_search <= 15 THEN
diameter := 1;
ELSEIF rank_search <= 16 THEN
diameter := 0.5;
ELSEIF rank_search <= 17 THEN
diameter := 0.2;
ELSEIF rank_search <= 21 THEN
diameter := 0.05;
ELSEIF rank_search = 25 THEN
diameter := 0.005;
END IF;
-- RAISE WARNING 'adding % diameter %', place_id, diameter;
secgeo := ST_Buffer(geometry, diameter);
x := insertLocationAreaLarge(partition, place_id, country_code, keywords, rank_search, rank_address, true, postcode, ST_Centroid(geometry), secgeo);
-- Create a bounding box with an extent computed from the radius (in meters).
secgeo := ST_Envelope(ST_Collect(
ST_Project(geometry, radius, 0.785398)::geometry,
ST_Project(geometry, radius, 3.9269908)::geometry));
PERFORM insertLocationAreaLarge(partition, place_id, country_code, keywords, rank_search, rank_address, true, postcode, geometry, secgeo);
END IF;