[OSM-talk] TIGER cleannup

[Beej Jorgensen]

Paul Fox wrote:
> but what about areas where the TIGER data is simply mis-aligned?  for
> instance, currently the TIGET data for san mateo county is off by about
> 200'.  and i think (i don't live in that area, so i'm not sure) that it's
> the entire county that's affected.

I'd be surprised if it's the entire county uniformly, since that's not 
the experience I've had in Alameda Co (different alignments in different 
places).

I remember reading on the census website somewhere that the map data 
came from a variety of sources, and no particular datum was used.

For big swaths that are mostly in alignment with just an offset, I'd use 
JOSM to select a bunch of points, and move them all at once into place. 
  But even then, I had to go back and straighten the roads out (the JOSM 
"make line" command is excellent for this).

> i think OSM needs to have a plan for dealing with updates for these
> sorts of issues, at least.

Some options that come to mind:

1) Don't ever update.  Let the OSMers do the updates.  Even the new 
census data at Lava Beds National Monument has errors in it (incorrect 
road names, foot trails marked as residential, old non-existent trails 
in data, missing trails, etc.)  In Chico, the new super-accurate data 
doesn't render or record freeway interchanges correctly.

2) Update everything that's not marked as "reviewed".  This seems like 
it would have hellish merge implications that I'm not sure are readily 
surmountable.  Plus I forget to mark stuff as reviewed half the time anyway.

3) Interactive regional updates... that is, maybe you get a chunk of new 
data, you download the OSM data, you run the as-yet-unwritten Magical 
Munger Program, and load the result back into JOSM.  Then you massage 
the data, verify it, and upload it.

I kinda like #1.  I think with more OSMers coming online all the time, 
it should be possible, too.

-Beej