hello marcello. what is your data model? dependng on the data model (if you have a column, lets say, rivername) you can use a group by clause and st_collect on your geometry field. ex:
select rivername, max(st_collect(the_geom)) from rivers group by rivername the intersects clause its up to you , depending on your néds. not tested, but should work. On 4/26/11, Marcello Benigno <[email protected]> wrote: > Hi All, > > I need a query that returns the greater length of river within a > watershed. Does > anyone have any suggestions on how I can solve this problem? > > The rivers are formed by segments. if each were a continuous line would be > easy. > > Here is a print-screen of the problem, in yellow is what would be the result > of > the query. > > Thanks in advance, > -- > *Marcello Benigno B. de Barros Filho* > Prof. do Curso Superior de Tecnologia em Geoprocessamento - IFPB > Mestre em Ciências Geodésicas e Tecnologias da Geoinformação - UFPE > http://profmarcello.blogspot.com > http://about.me/marcello.benigno > -- George R. C. Silva Desenvolvimento em GIS http://geoprocessamento.net http://blog.geoprocessamento.net _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
