[OSM-talk] TIGER 101

[Robert (Jamie) Munro]

David Groom wrote:
> 
>Robert(Jamie) Munro wrote: 
>> Later we could refine the script to use some sort of heuristic to
>> determine the best threshold for an area, based on the amount of data
>> around them, for example. So if there's two nodes within half a mile and
>> no other nodes for 100 miles around, merge the 2 nodes. If we run this
>> new script, as long as it doesn't produce false positives, it doesn't
>> matter if the end result isn't perfect. People can fix it later.
>>
>> I think what is important is that we get all of Tiger into the system
>> roughly so that people can then work on improving it.
> 
> I'd have to disagree with the above point.  Certainly in cities laid out on 
> a standard gridiron block pattern it seems to me there will be four times as 
> many nodes as needed, and with each segment being a way, an indeterminate 
> multiplication in the number of ways.  The data storage requirements, 
> together with the processing requirements of any planet.osm would seem to me 
> to be enough reason to stop the TIGER import.
> 
> Even if you look at TIGER data that is in OSM as a way of  source of 
> infomation from which to create "proper" OSM data, we currently don't have 
> the tools to effectively do this.

Yes, but we could write them, and should write them, not only for Tiger
but for other badly entered manual data. Storage really isn't a big
issue. The storage for Tiger can only be a fraction of storing GPS
points for a similar area if we were to gather them at the kind of
resolution needed to derive a map as good as the tiger map.

Also, you ignored my last point, which is probably the most important:

>> Otherwise we are
>> going to run into problems where someone has manually added a bunch of
>> roads, and Tiger wants to add the same roads. Unless we write something
>> very clever, we are going to get all the roads twice, and we won't even
>> be sure which is the most accurate.

We need to get the data in, so that people can see it, then we can clean
it, either manually, assisted (with tools like the new automatic
waymaker for JOSM - we could have an automatic node-merger for josm for
example), or fully automatically by a bot.

Robert (Jamie) Munro



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