Taylor Smock wrote:
> https://data.colorado.gov/Transportation/Counties-in-Colorado/67vn-ijga The
> `About` tab /claims/ that the data is Public Domain, but
> I would double check, just in case. (Some people I've talked to in county
> governments thought public domain meant the data was
> available for the public, /not/ that the copyright status was public domain,
> so I've learned to double check).
Thank you for that link, Taylor. While I am not an attorney, I am confident
enough that when a state government adds metadata of "License: Public Domain"
I can discern these data are ODbL-compatible. So I essentially re-drew OSM's
previously-broken (significant chunks missing) polygon for Clear Creek County
based on these data (and using the missing segment whole and unchanged). This
also required some massage of the data for part of the boundary shared with
Gilpin County. I attributed the link above in the changeset's source comment.
Especially in the area of James Peak (node/358916927), there are a number of
boundaries here (James Peak Wilderness Area, James Peak Protection Area, Grand
County, Continental Divide) which remain quite messy, with significant errors
that look to be around 20 to 30 meters. Indeed, the Continental Divide itself
(way/385331055) is tagged FIXME=improve precision.
While I don't often publicly complain about OSM's data, thanks to this dataset
submission to talk-us, I have noticed that a fair amount of county boundary
data in Colorado, while extant in OSM, have serious drift and accuracy errors —
hundreds of meters or even kilometers. As there exist ODbL-compatible data
which are clearly superior to OSM's current dataset, I recommend a dedicated
editor (or team) properly import these, conflating with existing data where
necessary (there appear to be many shared ways for edges of forest and
wilderness boundaries). This necessarily will be careful work, but OSM will be
much better for it.
I don't know how extensive these sorts of data errors are in other states. I
stumbled down this rabbit hole while using
http://layers.openstreetmap.fr/?zoom=5=40.2=-97.5=0B000FFFTFTTTFF
to quality-check county-boundary tagging. There are still some oddities
(several counties in California plus a score or so sprinkled around the lower
48) where I still do not quite understand why they remain in apparent error,
despite my "healing" some previously-broken boundaries. It could be I don't
fully understand this renderer's tiling schedule. But while this rendering has
improved some of those broken counties due to my improvements, some of them
stubbornly refuse to better render, despite seeming correct (and
correctly-tagged) polygons. Hm.
I'm "slowly watching" this (county boundaries which appear to have decayed to
brokenness, then repairing them), but I wanted to both share my activities more
widely with the US OSM community, as well as thank Taylor for his quick reply
to my request for state-issued county boundary data: I appreciate the pointer.
SteveA
California
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