- Original Message -
From: Pierre Béland infosbelas-...@yahoo.fr
To: talk-ca talk-ca@openstreetmap.org
Sent: Sunday, June 10, 2012 11:27 PM
Subject: [Talk-ca] Coastline rendering problems, Richelieu River
There are also Coastline rendering problems on the Richelieu river around
Saint-Jean-sur-Richelieu and Chambly. The OSM history changesets list
shows
many Non-ct data remove and recreate operations in the area done by user
PurpleMustang recently.
In Saint-Jean-sur-Richelieu, to correct the situation, I redrawed part of
the riverbank who was simply deleted.
In Carignan, Ile Ste-Marie is still flooded. There is no riverbank
relation
and I dont know if it has simply been deleted.
In Chambly, the river enlarges. There are two river that connect to the
basin and island around extremity of these two rivers. There is a relation
that was probably containing all the riverbanks roles (outer and inner).
But
the relation 305614 only contains to inner roles representing two islands.
In south-east part of Chambly Basin, there is a point and islands on the
east riverbank facing Fort de Chambly. The two islands included in the
relation are rendered as lake and the water as land.
see
http://www.openstreetmap.org/?lat=45.45798lon=-73.26392zoom=15layers=Mrelation=305614
Just
on the right, there is the Huron river coming in. The polygon
representing the part of the riverbank that join the Richelieu River is
lost. And there is way waterway=river for this river. This means that
the flow of water in the river is not indicated an no river name can be
showed on the map.
http://www.openstreetmap.org/?lat=45.46277lon=-73.25257zoom=16layers=Mrelation=1775822
Part of the Huron riverbank joining into the Richelieu near the point as
simply vanished.
see
http://www.openstreetmap.org/?lat=45.45798lon=-73.26392zoom=15layers=Mway=120716933
The riverbank around the basin is not included in the relation. This way
is
also improperly traced on the point facing Fort Chambly. It should be
closer
to the shore and not going around the tw islands.
see
http://www.openstreetmap.org/?lat=45.45798lon=-73.26392zoom=15layers=Mway=164251774
On this last image of the Basin, we see on top four islands for wich I
cannot find the coastlines.Ile Goyer, Ile Demers, Ile-aux-Lièvres,
Ile-aux-foins riverbanks have disappeared.North of these islands, the
Riviere L'Acadie is joining Richelieu River. The junction of the two
rivers
is improperly traced. Polygons 24346195 (Riviere L'Acadie riverbank) and
164254015 (Riviere Richelieu) simply do not join.
http://www.openstreetmap.org/?lat=45.47204lon=-73.2869zoom=15layers=Mrelation=1775822
I have to conclude again that these rendering problems are caused by
improper definition of coastlines and riverbanks.
I'm not sure coastlines are the current issue here. As you yourself have
pointed out there are missing ways, and ways drawn which do not meet the
full extent of the water area, and ways which are not included in the
relation.
I've tried to fix as much as I can
David
In JOSM, we can see what the riverbank should look like using Geobase
Imagery.
wms:http://ows.geobase.ca/wms/geobase_en?service=wmsrequest=GetMapversion=1.1.1SRS=EPSG:4326style=format=image/pngtransparent=truelayers=nhn:hydrography,nhn:networkWIDTH={width}height={height}BBOX={bbox};
Pierre
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