[postgis-users] distance between two end points of a line

[Shane Spencer]

Just dinking around.

select distance(
            startpoint(GeomFromText('LINESTRING( 0 0, 1 1 )')),
            endpoint(GeomFromText('LINESTRING( 0 0, 1 1 )'))
          );

    distance
-----------------
 1.4142135623731

confirmed via python CLI

>>> math.sqrt(1 + 1)
1.4142135623730951

make sure your geometries are LINESTRING, otherwise this may not work out
all that well for you.

On 9/18/07, temiz <temiz at deprem.gov.tr> wrote:
>
> hello
>
> I want to calculate distance between two end points of a line
>
> I used:
> select cat,
>
> distance(pointn(wkb_geometry,1),pointn(wkb_geometry,npoints(wkb_geometry)))
> from spelhey;
>
> it gives all zero
>
> cat | distance
> -----+----------
>    1 |        0
>    2 |        0
>    3 |        0
>    4 |        0
>    5 |        0
>    6 |        0
>    7 |        0
>    8 |        0
>    9 |        0
>   10 |        0
>   11 |        0
>   12 |        0
>   13 |        0
>   14 |        0
>   15 |        0
>   16 |        0
>   17 |        0
>   17 |        0
>
> can you tell me what happened ?
>
> regards
>
>
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