At 2012-07-19 13:41, Phil! Gold wrote:
* Martijn van Exel <m...@rtijn.org> [2012-07-19 14:22 -0600]:
> On Wed, Jul 18, 2012 at 11:42 PM, Toby Murray <toby.mur...@gmail.com>
wrote:
> > Any other common problems that people have seen?
>
> Another thing I find is a lot of leftover stray nodes without any tags.
> I select them in JOSM with type:node tags:0 -child and delete them in
> one fell swoop.
Eeek! Be very careful with this! The unconnected, untagged nodes were
left deliberately to facilitate recreation of roads, particularly the case
where a decliner split a TIGER way but did not change its geometry. I've
been making use of these nodes in South Carolina to reconstruct the roads
there.
That _is_ a nice feature. One thing I would do (in JOSM) when first loading
an area to work on is run the validator. This will find those orphan nodes,
as well as crossing ways that don't intersect, etc. - indicators of things
that need to be fixed.
While it might seem easier sometimes to delete and re-draw objects, be
careful with objects that have source/source_ref values, as this says that
a user has edited/confirmed that object (with the exception of some of the
automated import sources), which should be considered the highest form of
authenticity. Be careful of intersections with turn restrictions and their
connecting roads. These render with little restriction signs on/near the
intersection in JOSM and Potlatch.
Unfortunately, TIGER11 still has naming inaccuracies. I recently did this
neighborhood with some new construction in Yorba Linda, CA:
http://www.openstreetmap.org/?lat=33.8987&lon=-117.8017&zoom=14&layers=M
and put note tags on a number of roads that required research that
ultimately contradicted TIGER. I think there were a couple more that were
wrong that I did not annotate. That would be roughly 1-5% of the roads in
the area, and a larger %age of the new roads. I've had a similar experience
with new construction at Fort Irwin, CA and Victorville/Hesperia, CA. It
seems to be worse for new construction areas, presumably because TIGER
eventually gets some feedback to correct it. The issues are often obvious -
look for mis-spellings of common words, lack of prefix or suffix (i.e.
missing Via, Camino, St, Ave, Blvd), etc. Also look for names that are
different from the pattern used in a given area, e.g., Piazza Maria, Piazza
Angela, Piazza Gina, George, Piazza Donnatella. "George" is probably wrong
here (missing prefix, non-Italian man's name).
I will say that TIGER11 road positioning and connectivity generally seems
good now, even enough for GPS guidance.
Bing imagery is available down to zoom 19 (~26cm/pel) in virtually any area
with a road, and even zoom 21 (~6cm/pel) in the most populous areas (though
some of the patches close to downtown LA are "jagged", and look better at
z19). I've confirmed that alignment accuracy is within about 5m of known
benchmarks (personal surveys, FAA VORs, USGS benchmarks, CORS stations,
etc.) at many points - enough to satisfy me that the imagery can be used.
--
Alan Mintz <alan_mintz+...@earthlink.net>
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