Hi Kurt, can you send me some example data that I can use to test the function?
Rodrigo. On 7/1/07, Kurt Schwehr <[EMAIL PROTECTED]> wrote:
Hi All, This is only sort of a postgis question, but I figured I'd try here in addition to the postgres newsgroup. I am pretty new to SQL and having trouble trying to formulate a query from what I have been reading in a couple of books (and got a suggestion from a friend that included cursors and is totally over my head). I would really appreciate any help getting this figured out. I am trying to group track positions from a ship into sections split by gaps of no recorded position from a particular ship for a period of time (say 60 minutes). I have a table "position_reports" something like this: key SERIAL PRIMARY KEY, ship_id INTEGER, position GEOMETRY, received TIMESTAMP, received_sec INTEGER position is a postgis POINT. The received_sec is the seconds since the epoc from the original logs that I have converted to a TIMESTAMP. Figure this query might be easier with one over the other? The goal is to be able to generate LINESTRINGs from each ship by time block that I record the ship. Right now, I end up doing a MakeLine for each ship which joins different passes of the ship through an area (which has ships flying over land quite frequently :) 1 123 someXY 2007-Jan-05 12:01 2 123 someXY 2007-Jan-05 12:04 3 123 someXY 2007-Jan-05 12:13 # more than 60 minutes gap, so split groups here 4 123 someXY 2007-Jan-05 15:23 5 123 someXY 2007-Jan-05 15:46 6 123 someXY 2007-Jan-05 15:53 7 123 someXY 2007-Jan-05 16:01 Thanks, -Kurt _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
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