I also seem to have observed that, at least in rural New Mexico where I do most of my mapping, GNIS features like historic places seem to have only been entered to the resolution of what town they were in, and then all ended up at something like the centroid of the town or county limits. The result can be rather odd - before I moved them all to more correct locations, the parking lot of a particular bank in Socorro, NM contained over a half dozen historic homes. What an amazing place to visit!
So this is another thing to keep in mind, it seems like the GNIS locations may be quite a bit less granular for certain types of features. The historic features are a good example as they were presumably all taken from the registry and so they *do* exist, but it can take a lot of legwork to figure out where. -- Jesse B. Crawford https://jbcrawford.us je...@jbcrawford.us GPG 0x4085BDC1 On Sat, Sep 30, 2017, at 11:05 AM, Mark Wagner wrote: > On Sat, 30 Sep 2017 15:11:06 +0700 > Dave Swarthout <daveswarth...@gmail.com> wrote: > > > "Second, many entries have their coordinates specified using the old > > NAD 27 datum, but somewhere along the line, that fact was lost and the > > coordinates were assumed to be in either NAD 83 or WGS 84. This > > results in an offset that increases the further you go from central > > Indiana; the offset in Alaska is upwards of a hundred meters to the > > west." > > > > Wow, thanks for that. If I understand what you're saying, this means > > many of the old GNIS nodes will be positioned about 100 meters east > > of where they should be? Or do I have your statement turned around? > > Depending on where in the process the error was made, it could go > either way, but in my experience, the nodes are usually positioned too > far to the east. > > -- > Mark > > _______________________________________________ > Talk-us mailing list > Talk-us@openstreetmap.org > https://lists.openstreetmap.org/listinfo/talk-us _______________________________________________ Talk-us mailing list Talk-us@openstreetmap.org https://lists.openstreetmap.org/listinfo/talk-us
