Add drainage_density, sumwetted surface downstream, nb of tributaries ...

[cedric]

Hilaire :

ceate temporary table allsegment as (
select seaidsegment, idsegment, surfaceunitbvm2, wettedsurfacem2,lengthm,distanceseam from dbeel_rivers.rna rna
left join dbeel_rivers.rn out using(idsegment));
create index tmpidx on allsegment using btree(seaidsegment);
select db.idsegment, count(down.idsegment)/sum(down.surfaceunitbvm2) as densite_hydraulique,
sum(down.lengthm)/sum(down.surfaceunitbvm2) as densite_drainage,
sum(down.wettedsurfacem2) as available_hab from allsegment db 
left join allsegment down on down.seaidsegment=db.seaidsegment 
and down.distanceseam<=db.distanceseam group by db.idsegment;