How to make a polygon out of 3000 points?

Question

PostgreSQL

There is a table of about 3000 points (latitude, longitude). These points outline the border of the state. How to create a polygon from these points and check if point X is contained in this polygon?

Answer 1

More or less like this:

CREATE TABLE country_polygon AS
  SELECT points.country, ST_MakePolygon(ST_MakeLine(ST_MakePoint(points.longitude, points.latitude) ORDER BY points.num)) As geom
  FROM points
  GROUP BY points.country;
SELECT ST_Contains(geom,point) FROM country_polygon;

based on ST_MakeLine and ST_Contains