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mysqlpoint-in-polygon

Search a table for Point in Polygon using MySQL

I have create a table (municipal_border), in MySQL 5.5, that holds some boundaries.

CREATE TABLE `municipal_border` (
  `boundary` polygon NOT NULL,
  `municipalID` int(10) NOT NULL,
) ENGINE=InnoDB

The field municipalID is not unique.

I'm using the code below to test if a point belongs into a polygon.

set @r = (SELECT municipal_border.boundary FROM municipal_border WHERE municipalID=9001);
set @p = GeomFromText('POINT(24.1621 41.0548)');
select if(contains(@r, @p), 'yes', 'no');

The first statement set @r = ... returns just one row and I selected it specially for testing. It works just great.

What I want to do is to search the whole table (erasing, in other words, the WHERE part from the SQL question) and find in which polygon the point is in.

Solution

  • After a night sleep I found the following solution.

    set @p = GeomFromText('POINT(23.923739342824817 38.224714465253733)');
select municipalID FROM ecovis.municipal_border
where ST_Contains(municipal_border.boundary, @p);

    It is working for MySQL 5.6.1 where ST_ prefix function have been implemented. Although I haven't any measurments from a classical approach (x-ray algorithm) I believe that is quite fast. It needs 0.17 seconds to locate a point in 2700 polygons with some polygons having well more than 1,500 points.