Take the 2-minute tour ×  The ST_length() function returns the
length of a linestring but not in meters.  Is there a function
like ST_Length() but in meters?.   share|improve this question
add comment  2 Answers  up vote 7 down vote accepted
St_Length() returns the length in the units of its Spatial
Reference System. If you want to get meters, you will need to
transform your feature to a different SRS that uses meters as
units. This can be done on-the-fly, so don't worry about writing
out another data set.  SELECT
ST_AsText(ST_Transform(the_geom,26915)) from my_table;  In this
example, SRID 26915 is UTM Zone 15 N, NAD83.  share|improve this
answer Or simply add your own field and manage the calculation
yourself. NOTE you have to write your own trigger or recalculate
it on changes in your lengths. –  Brad Nesom Oct 11 '12 at 4:12
add comment  Examples of SQL request: how-to-calculate-length-
of-polyline-geometry-for-several-tables-in-postgis  SQL request
(length in km (/1000 -delete for meters)):  sum(ST_Lengt