[OSM-dev] Overlapping polygons - verboten or not?

[Ben Supnik]

Hi Frederik,

Hrm...yeah, it's just a question of: in what form.  The entire tool 
chain for creating X-Plane scenery is open source, and we're looking 
into _some_ way to have it run on a semi-continual basis.  (Historically 
we 'recut' the world when we release a new paid major version, but our 
users have quite vocally requested that we sync with OSM more frequently 
than that :-)

There are two possible problems:

1. By the time we do our sanity analysis, the data has been processed 
six ways from Sunday; the actual resulting 'notices' may not be directly 
applicable back to OSM.  We certainly could come up with coordinates 
(e.g. "a problem of type X happened at this location") but, for example, 
we purge out node/way OSM IDs to save memory when processing large files.

2. Some of what we consider wrong might really be DB problems, but 
others might just be because X-Plane's idea of the world can be limited, 
and there are real-world exceptions.  So...how do you filter out false 
positives from problems that need to be fixed?

Still, there are a bunch of interesting things we could do here.  We 
integrate OSM against other data sets, so for example, we have a rough 
notion of the amount of water in the area (from raster data) and can 
thus detect areas where major water bodies have gone unmapped.

cheers
Ben

On 4/20/11 11:58 AM, Frederik Ramm wrote:
> Hi,
>
> On 04/20/11 17:51, Ben Supnik wrote:
>> 3. We sanity check the incoming data. This is fairly specific to our app
>> case and may not be appropriate for others. If a way goes straight up a
>> mountain at a 80 degree slope and its type is motorway=trunk, we throw
>> it out. It's much more likely that there's a conflict between our
>> elevation data and the road than that there's a road going up at that
>> slope, and frankly it's going to look stupid in X-Plane anyway. So we
>> protect ourselves from data problems by being more committed to
>> 'plausibility' than 'accuracy'.
>
> Any chance you can make these cases available - on a regular basis,
> ideally - so our users could, if interested, have a look and fix them?
>
> Bye
> Frederik
>
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