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Pour les lacs, dans la couche lacs upstream_a correspond à cont_pixel du riversegments aval dans la couche riversegments . #63

= How to join the lakes with the riversegments layer =
Differents "types" of lakes :[[BR]]
[[Image(source:data/Docs/trac/Lakes/Lakes4.jpg,500px)]] [[BR]]
Lake 1 : upstream_a=350 = cont_pixel du riversegement 1 [[BR]]
Lake 2 : uptream_a=60826=cont_pixel du riversegment 2  (and pfafstette lake2 = pfafstette riversegment2)[[BR]]
Lake 3 : upstream_a=0 (but several cont_pixel=0 in riversegments table)[[BR]]
Same wso_id for the lakes 1, 2, 3 and same wso_id for the five riversegment (they are in the same bassin)[[BR]]

{{{
select r.wso_id, r.wso1_id, cont_pixel, upstream_a, l.wso_id from ccm21.riversegments as r inner join ccm21.lakes as l on r.cont_pixel=l.upstream_a and r.wso_id=l.wso_id where r.wso_id=291112 order by cont_pixel
}}}

 * Some are on the same river segement --> one cont_pixel in riversegments = one upstream_a
 * Some cross different river segements --> severals cont_pixel = one upstream_a
 * Some are not on a river segement
||[[Image(source:data/Docs/trac/Lakes/Lakes3.jpg,500px)]]||[[Image(source:data/Docs/trac/Lakes/Lakes1.jpg,500px)]]||[[Image(source:data/Docs/trac/Lakes/Lakes2.jpg,500px)]]||

The "shape_area" variable is more accurate than "area" variable, same as "shape_leng" and "perimeter"[[BR]]