Description

Returns the geometry as an Encoded Polyline. This is a format very useful if you are using google maps

Availability: 2.2.0

Examples

Basic

SELECT ST_AsEncodedPolyline(GeomFromEWKT('SRID=4326;LINESTRING(-120.2 38.5,-120.95 40.7,-126.453 43.252)'));
--result--
|_p~iF~ps|U_ulLnnqC_mqNvxq`@

Use in conjunction with geography linestring and geography segmentize, and put on google maps

-- the SQL for Boston to San Francisco, segments every 100 KM
SELECT ST_AsEncodedPolyline(
	ST_Segmentize(
		ST_GeogFromText('LINESTRING(-71.0519 42.4935,-122.4483 37.64)'), 
			100000)::geometry) As encodedFlightPath;

javascript will look something like this where $ variable you replace with query result

<script type="text/javascript" src="http://maps.googleapis.com/maps/api/js?libraries=geometry"></script>
<script type="text/javascript">
     flightPath = new google.maps.Polyline({
            path:  google.maps.geometry.encoding.decodePath("$encodedFlightPath"),
            map: map,
            strokeColor: '#0000CC',
            strokeOpacity: 1.0,
            strokeWeight: 4
        });
</script>

See Also

ST_LineFromEncodedPolyline, ST_Segmentize