31 lines
696 B
PL/PgSQL
31 lines
696 B
PL/PgSQL
-- Return a line for the Great Circle between two points
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--
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-- start_point geometry : The origin of the line
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-- end_point geometry : The distination of the line
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-- retruns geometry
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create or replace function CDB_GreatCircle(start_point geometry ,end_point geometry ) RETURNS geometry as
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$$
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DECLARE
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line geometry;
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BEGIN
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line = ST_Segmentize(
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ST_Makeline(
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start_point,
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end_point
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)::geography,
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100000
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)::geometry;
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if ST_XMax(line) - ST_XMin(line) > 180 then
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line = ST_Difference(
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ST_Shift_Longitude(line), ST_Buffer(ST_GeomFromText('LINESTRING(180 90, 180 -90)',4326), 0.00001));
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end if;
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return line;
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END $$
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LANGUAGE 'plpgsql'
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