[postgis-users] Newbie - get total distance travelled from query of points

[Joe Roberts]

Hi,

I am very new to PostGIS, and I'm stuck with what I hope is an easy
problem to solve.

I have a table which contains a list of points, originating from a GPS
device's lat/long output. I want to get the distance travelled. I have
the following query, but the result (distance) looks far to low:

SELECT ST_Length(St_MakeLine(point))/1000 as distance
FROM (
      SELECT point FROM points
      ORDER BY timestamp
) as p

I know the route was over 5 miles (probably about about 8.4 km), but
the query returns 0.000106496.

Can anyone see what I am doing wrong? Is it my query, or could it be
my data?

Many thanks

Joe
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