Michael, I'm not sure what a multi part line feature class is in ESRI. I assume probably MULTILINESTRING. Are you trying to get one geometry out per track_id or 2 records. If 1 record - then that would be a LINESTRING If 2 records then that would be a MULTILINESTRING If I understand you correctly - I think you want to use the ST_MakeLine aggregate function in conjunction with the non-aggregate ST_Collect http://postgis.refractions.net/documentation/manual-svn/ST_MakeLine.html
http://postgis.refractions.net/documentation/manual-svn/ST_Collect.html So I'm going to assume you are trying to do 2. So there would be a little twist. It would look something like the below. The below will generate a multilinestring for each track_id where the multiline is composed of 2 linestrings - one for class1 and one for class2 SELECT gps.track_id, ST_Collect(ST_MakeLine(CASE WHEN class1=1 THEN gps.the_geom ELSE NULL END), ST_MakeLine(CASE WHEN class2=1 THEN gps.the_geom ELSE NULL)) As newgeom FROM (SELECT track_id,ST_SetSRID(ST_MakePoint(long,lat),4326) As the_geom, class1, class2 FROM raw_data ORDER BY dtime, id) As gps GROUP BY gps.track_id Hope that helps, Regina ________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Michael Diener Sent: Friday, October 17, 2008 6:35 AM To: [email protected] Subject: [postgis-users] points to multi-linestring or multipart linestring Hi, How do I create a multipart line feature class known in the ESRI world in Postgresql/postgis ? What feature type is it equivalent to...umm... multilinestring or linestring or...xxxx in Postgresql PostGIS? I have a points geom table of coordinates with attributes. Using these attributes I want to generate a linestring or multilinestring where ever the attribute is active with a 1. So I need some SQL statement here to do this somehow. below is an example of how the raw data looks the attributes are class1 and class2 table name: raw_data (type: point srid 4326) id;track_id;Lat;Long;Alt;DTime;SoG;DOP;class1;class2 1,35,46.596805,14.27998,392.4,2008-10-10 06:48:24,9.11184,8.4,0,1 2,35,46.5969333333333,14.2799983333333,390.2,2008-10-10 06:48:29,9.76004,8.4,0,1 3,35,46.597085,14.2800533333333,388.2,2008-10-10 06:48:38,8.01916,8.4,1,0 4,35,46.5972883333333,14.280115,387.8,2008-10-10 06:48:46,8.48216,7.8,1,1 5,35,46.5973966666667,14.280215,386.9,2008-10-10 06:48:53,9.8156,7.8,1,1 6,35,46.5975683333333,14.2803133333333,386.3,2008-10-10 06:49:01,8.48216,7.8,0,0 7,35,46.597785,14.2803816666667,387.3,2008-10-10 06:49:08,8.77848,7.8,1,1 8,35,46.597955,14.2804516666667,386.3,2008-10-10 06:49:14,11.03792,7.8,1,1 9,35,46.5981683333333,14.2805466666667,386.9,2008-10-10 06:49:21,10.2786,7.8,0,1 class1 0,0,1,1,1,0,1,1,0 class2 1,1,0,1,1,0,1,1,1 For class1 I should have 2 new line segments For class2 I should have 3 new line segments thanks for any help rusty on the SQL michael [EMAIL PROTECTED] <http://www.gomogi.com> ----------------------------------------- The substance of this message, including any attachments, may be confidential, legally privileged and/or exempt from disclosure pursuant to Massachusetts law. It is intended solely for the addressee. If you received this in error, please contact the sender and delete the material from any computer. _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
