2009/12/3 Ian Dees <ian.d...@gmail.com> > On Thu, Dec 3, 2009 at 11:01 AM, Thea Clay <t...@cloudmade.com> wrote: > >> Hi guys, >> I am so excited that more land use imports are in the works. They make >> such a huge visual difference. Check out the border between a state with the >> import complete and one without: >> http://www.openstreetmap.org/?lat=34.896&lon=-85.408&zoom=9&layers=B000FTF >> >> Although the lower-detail zooms might look marginally better (I would say > they're way too cluttered right now...), the import was not done very well > for two main reasons: > > 1. All of the areas were imported with overlapping edges. This means there > is *tons* of duplicate information in the database. I learned my lesson with > the counties import: overlapping edge imports like this should be broken > apart and use relations for the borders. > > 2. The resolution of the landuse information is very low. If you zoom in > and use Potlatch to see what the aerial images look like, you can see that > in most cases the polygons don't come close to matching the actual landuse. > in the future, we should make sure that imports are high-enough resolution > to be useful in our datasets. 1:24k is the minimum and even that is not > useful in some cases. > > I'm not trying to belittle the effort, I just want to make sure we don't > repeat the same mistakes on other huge imports like this. > > Well it is now imported, difficult to remove the data now :) It looks great though even if there are some issues. I agree with you that an overlap analysis should have been performed initially.
Emilie Laffray
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