[Talk-us] Updating unchanged TIGER imports to TIGER 2013

Mike N niceman at att.net
Tue Mar 12 21:00:01 UTC 2013

On 3/11/2013 10:10 PM, Eric Fischer wrote:

> I would like to update OpenStreetMap with as many of the corrections
> that have been made to TIGER as can be applied to Open StreetMap without
> altering anything that has been edited directly in OSM.

   Thanks for coming up with this; I've been hoping for some methods of 
applying the new TIGER but haven't had time to work on it myself.  This 
algorithm is good because it preserves existing work.

> Although this process will never change the topology of the network,
> there can occasionally be some odd-looking results where someone has
> moved (but not to the correct location) an OSM node that connects to an
> updated TIGER node, sometimes causing streets to have abrupt turns or to
> cross over themselves. I'm not sure what to do about these cases other
> than call them out and fix them manually.

   The results of application will depend on both the original data and 
the 2012 data.  For layouts with 'regular geometry' - roughly square, 
rectangular, or rhomboid layouts, the results will be generally good. 
For curved roads with poor original TIGER geometry, I would expect the 
result to be very irregular without manual correction.   I've seen this 
type of road network in very hilly or mountainous areas.

> There are also many cases where TIGER 2013 knows about streets that were
> not built or not mapped in TIGER 2006. Some of these have also been
> added by OSM contributors but many others have not been. I think the
> right thing to do for these is to generate speculative OSM equivalents,
> but rather than checking any of them in directly, use something like
> MapRoulette to review each of them to see whether or not it ought to be
> adopted.

   Ideally, all the new street data should be reviewed before bringing 
it in; depending on the origin, most of it needs to have the alignment 
tweaked and connectivity verified against Bing Aerials.

   It would be nice to be able to view the results in JOSM before 
uploading them, even if another tool is used for upload; I'm not sure 
how to do that.

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