Yes. Experiment with
- ST_Line_Locate_Point(linestring, Point) - which returns a percentage
along the linestring the point occurs.
- ST_Line_Interpolate_Point(linestring, location) - which accepts a
"percentage along" and returns the interpolated point along the
linestring.
Since these functions accept a linestring, you could extract the
exterior ring of your country polygon.
Something like:
SELECT
ST_Line_Interpolate_Point(
ST_Exterior_Ring(the_geom),
ST_Line_Locate_Point(ST_Exterior_Ring(the_geom), gps_pt)
)
FROM ...
Cheers,
Kevin
Doug Fischer wrote:
...
Is there some way to determine the closest point in the border of the
country to the point collected by the GPS in order to use the
distance_sphere() or distance_spheroid() functions for a more precise
measurement?
Thank you very much for any help.
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