Get polygon points mysql

问题

i have created a table in mysql to store polygon data:

CREATE TABLE geom (g GEOMETRY);

And i inserted a polygon into it, using the following syntax:

INSERT INTO geom (g)
VALUES(PolygonFromText('POLYGON((
9.190586853 45.464518970,
9.190602686 45.463993916,
9.191572471 45.464001929,
9.191613325 45.463884676,
9.192136130 45.463880767,
9.192111509 45.464095594,
9.192427961 45.464117804,
9.192417811 45.464112862,
9.192509035 45.464225851,
9.192493139 45.464371079,
9.192448471 45.464439002,
9.192387444 45.464477861,
9.192051402 45.464483037,
9.192012814 45.464643592,
9.191640825 45.464647090,
9.191622331 45.464506215,
9.190586853 45.464518970))')
);

Now how can i get back the vertices (points) of this polygon in mysql? Why i am asking means, later i want to find whether a point is inside a polygon. And to achieve this, i hope i need the polygon vertices.

回答1:

If you want the WKT back: SELECT AsText(g) FROM geom;

回答2:

If you want to find whether a point is in a polygon, you don't need to derive the individual vertices to do that. There's a function in MySQL (5.6+) for this:

SELECT ST_Contains(PolygonFromText('POLYGON((
9.190586853 45.464518970,
9.190602686 45.463993916,
9.191572471 45.464001929,
9.191613325 45.463884676,
9.192136130 45.463880767,
9.192111509 45.464095594,
9.192427961 45.464117804,
9.192417811 45.464112862,
9.192509035 45.464225851,
9.192493139 45.464371079,
9.192448471 45.464439002,
9.192387444 45.464477861,
9.192051402 45.464483037,
9.192012814 45.464643592,
9.191640825 45.464647090,
9.191622331 45.464506215,
9.190586853 45.464518970))'), PointFromText("POINT(10 42)")
);

来源：https://stackoverflow.com/questions/5105035/get-polygon-points-mysql

标签

php

mysql

polygon