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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