[OSM-talk] Element on OSM which don't exist in real life

[Richard Welty]

> Thank Frederik. I'm actually working in JOSM, and I've spotted those 
> import tags - but as I still feel like a newbie when it comes to all 
> things OSM, I thought I'd check with the community so that I don't do 
> something silly.

Welcome to TIGER and GNIS!

what Fredrick said is true; i'm going to add some US specific info.

there is some bad data in the GNIS import. when i encounter obviously
bogus objects from the GNIS import, i just delete them. just the other
day i deleted a GNIS object which suggested someone had a heliport in
their back yard a little south of Albany NY. i didn't see a heliport.

as for non-existent roads in TIGER, it happens. there are various
reasons for it, but if you're looking at unreviewed TIGER (look for
a tiger:review=no tag) and you can't find the matching real world
entities, you are fully justified in deleting them. if you do verify
a road exists, then also verify its topology (is it hooked up the way
the map shows), its name (from the road signs) and its location (bing
imagery is good for this, as are personally collected GPS tracks).
if those check out you are justified in removing the tiger:reviewed
tag (if you are fastidious, you can change it to yes, but most of us
just delete it. fewer mouse clicks that way.)

as for the reasons - TIGER data quality varies quite widely, seemingly
from county to county. it is getting better - if you compare the 2005
data which is what we imported to 2013 data you can see the improvement.
but there are cases where obviously someone sketched out a map then
freehanded it into the database, and there are cases where a developer
got their roads into the database before they failed to finance the
development project.

if you look at the image dropdown, you will see a tiger 2012 underlayment.
you can use this to compare what's in OSM to the 2012 data set.

so don't be afraid to fix it. there is bad data in TIGER. mistakes
happen.

richard


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