On Mon, Jun 17, 2013 at 1:38 PM, Richard Welty <[email protected]>wrote:
> how will you tag so as to allow correlation between previously imported > USPS > data and updated USPS data? how do you propose to resolve conflicts where > a mapper has modified previously imported USPS data and the new USPS data > is different from the prior data? how do you propose to determine if a > deletion > is proper or an error on the part of the USPS? Overall, the answer is that the automated conflation process produces a JOSM changeset, which is then stepped through using the JOSM todo plugin. The human makes the final determination prior to upload. In the case of something like pickup hours, where the USPS determines the hours, I would choose to take the USPS data over the hand mapper data (that is, assuming the decision is made to import pickup hours at all). For each key a decision needs to be reached as to how authoritative the data is. Based on a bicycle survey of the nearest 50 post boxes to my particular home location, I found a 100% match on the ground to the USPS data in both general location and pickup hours. OSM had far better positions, but was missing 25% of the postboxes completely The sample was drawn from: http://open.mapquestapi.com/xapi/api/0.6/node[amenity=post_box][bbox=-122.42446983717664,37.80767673705407,-122.14981163406262,37.92963831776495] you need to flesh out the update process, "conflation" is easier to say > than it is to do. > It appears (so far) that the USPS data's primary key is a nearby postal address. E.g. the box is known to USPS as "1301 Solano Avenue". So that means importing some form of address data into the post box nodes. The conflation operates on two hints: physical location and address. If both match, that's a high confidence operation and may be automated. If the location is off by more than (say) 20 meters, or the address does not match, there is no automated conflation. Fortunately post boxes are generally far enough apart that physical conflation is possible within GPS resolution. (I've worked on projects where that is not true). Thus a hand mapper deleting keys only lowers the conflation confidence, it does not make it unfeasible. -- A candidate deletion is an "amenity=post_box" that has an address in OSM, but no match can be found in the USPS database. Before deletion any nearby amenity=post_box should be checked and validated: most likely the nearby node is a duplicate.
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