----- Original Message -----
From: "Dan Ball" <[email protected]>
To: <[email protected]>
Sent: Monday, August 29, 2011 7:35 PM
Subject: [OSM-newbies] Fixing the Mississippi River
Hi all,
I've been tinkering OSM data for the first time over the last week and
Dan
welcome to OSM.
finding my way around. I've stumbled upon something interesting: the
riverbank of the Mississippi River seems to be missing between Maxey
Island,
IL
(http://www.openstreetmap.org/?lat=39.0043&lon=-90.6892&zoom=13&layers=M)
and just south of Quincy, IL
(http://www.openstreetmap.org/?lat=39.897&lon=-91.4429&zoom=12&layers=M).
It
seems the missing riverbanks cause the river to "disappear" between these
two areas on the openstreetmap.org viewer.
I'd be happy to contribute if the data are indeed lacking here – I've just
never edited OSM data and wanted to clarify a few things before I started
messing with such a major geographic feature:
1) The source of the riverbank data appears to be NHD where the features
end
on both sides. Should these features be connected by hand, or should this
hydrography data be imported from elsewhere?
I'd guess that in this instance its easier and quicker to trace these from
the available aerial imagery
2) Does it matter whether the nodes are placed in a clockwise or
counterclockwise matter?
Not really, though convention always was that outer ways got drawn
clockwise, and inner ways anti-clockwise, but this became unnecessary when
multpolygons started to be used
3) Should the addition be one multipolygon, or broken up into multiple
multipolygons?
Definitely break this up into smaller sections. Its difficult to give any
hard and fast rules on how many small sections to break this into, but if
you have a look at the existing sections to the north and south of the
missing section, I'd say they look OK.
David
Thanks!
Dan
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