[Talk-ca] Simplifying CanVec imports

[Samuel Longiaru]

Good Morning Everyone,

For the past couple of weeks I have been importing CanVec data into an
area southwest of Kamloops.  There was very little (if any) existing OSM
data in the area.  I've gotten into a bit of a rhythm, merging and
stitching all of 92I07 and about half of 92I10 but started becoming
concerned about the high data density, particularly associated with
streams in the area.  Most import files at the level of 92 I 07.0.0 for
example, are runnning 10-15k nodes.  At that rate, that is somewhat near
200,000 nodes for an area at the level of 92I07.  Yikes!  I guess the
question in my mind is just how many data do we want to import at this
level and what are the practical implications for server processing and
overload.  I expect that this level would be fairly consistent across
most of Western Canada. Even now, I haven't been able to call up a
complete map in the openstreet.org view tab for the past 4 or 5 days...
25-50% of the map being covered with "... more OSM coming soon" tiles.

I looked at the Simplify Way function in JOSM and applying it to just
the water data, have been able to eliminate 5-8k nodes from each file,
thereby cutting the data in nearly half.  I really don't see any
significant degradation in the map quality as a result.  Without
simplifying, the data nodes in some places are incredibly (and
undeservedly ) dense.  The only discussion I've been able to find on the
simplify tool is some rather old discussion that took place during
development.  

So just wondering if simplifying these data is a reasonable approach.
Right now, I am going back to the imported areas, calling them up from
OSM, simplifying the water, and re-uploading the simplified data.  In
the future, I will just simplify in JOSM before uploading the file in
the first place.  Anyway, does anyone have any issues with my approach
here?  Is it worth simplifying  or am I being overly concerned about
data density and its longer term implications?

Thanks,

Sam Longiaru
Kamloops, BC 

 
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