[Talk-ca] Lake Simcoe - two versions?

[Frank Steggink]

On 11-05-30 09:15 PM, Me (Gmail) wrote:
> I've been working on improving the Barrie, Ontario area, and I'm
> trying to figure out what is going on with/what to do about Lake
> Simcoe.
>
> There are multiple CanVec-imported ways that together make up a fairly
> detailed, accurate representation of the lake. A single low-detail way
> [1] is overlapping these, and obscures the accurate detail in many
> places when rendered [2].
>
> [1]: http://www.openstreetmap.org/browse/way/4997263
> [2]: http://dl.dropbox.com/u/2398828/lake-simcoe-josm.png
>
> Not having much experience dealing with large or tiled objects in OSM,
> my question is if the low-resolution object is serving a purpose, and
> whether I should bother editing it so as to not overlap with the
> high-detail version, or whether it can just be deleted.
>
Hi AJ,

The Canvec version is clearly better, so the lowres version can be 
deleted. It was probably one of the features being traced when only 
Landsat imagery was available. In my opinion this cleaning up should 
have been done during the import of the Canvec sheet. Otherwise this 
import gets more characteristics of a "bad import" (by leaving duplicate 
features), which we should prevent. (Note that there are also some 
people who think that user traced features are always better than 
imported features, but in this case the difference is evident, and 
nobody has bothered yet to trace the shoreline from the Bing imagery.)

What might have caused this is that Lake Simcoe overlaps several sheets, 
so it can't be deleted at once. Wat I usually do is to cut the part of 
the coastline which is overlapping the sheet being imported, and connect 
the existing coastline to the new one. An example of this can be seen in 
the southeast part of Lac Saint-Jean in Québec: [1]. This is also how 
I've dealt with the Saguenay river, and also with the St. Lawrence 
coastline. This can best be done asap, because you never know for sure 
when you continue with the rest. It is a bit more work, but in my 
opinion it's much better than confusing or even annoying others.

Frank

[1] http://osm.org/go/cLD8wZR--