Re: [Talk-us] Tiger 2008 Data

2008-10-29 Thread Alan Millar 
 does the census bureau publish any sort of a diff, or delta dataset?
 i'd think that just in terms of raw crunching that having just the
 differences from year to year would save a lot of work, both manual
 and CPU-cycles.

Not that I've seen.  What they do publish is the TLID and TZID numbers in
their data.  These are permanent segment and node numbers which do not
change from one Tiger release to the next, so you can do your own
comparisons and updates.  It also means that if you want to synchronize
with them, you need to keep and maintain their TLID and TZID numbers.

- Alan



___
Talk-us mailing list
Talk-us@openstreetmap.org
http://lists.openstreetmap.org/listinfo/talk-us

Re: [Talk-us] Tiger Data 2007

2008-10-29 Thread Dale Puch 
On Wed, Oct 29, 2008 at 11:07 AM, Dave Hansen [EMAIL PROTECTED] wrote:

 On Tue, 2008-10-28 at 16:29 -0700, Alan Brown wrote:
 
  When that data is imported - how will you know that a missing road was
  intentionally deleted from OSM, or simply missing from the dataset?
  If they reappear, it would be rather irritating to me.  It's not
  overruling me, in the sense that the old geometry no longer exists
  for you to see that I've editted it.
  You could merely import changes to TIGER - that would be part of being
  paranoid - and that would address this situation.

 That's a really good, and really functional idea.

 We could create convert old TIGER-OSM and new TIGER-OSM.  Then, create
 a JOSM-style diff and apply it to the database.  If it applies cleanly,
 commit it.  Otherwise, throw it away and move on.

 -- Dave


 ___
 Talk-us mailing list
 Talk-us@openstreetmap.org
 http://lists.openstreetmap.org/listinfo/talk-us


I would suggest a little more than that.  The above eliminates what is
unchanged and need not be imported.  You will need to also diff the old
tiger with tiger tagged data in OSM.  Only what matches is ok to delete and
replace with the new import.

So you end up with:
Same in old and new tiger = don't import as it is un-improved
Not in old tiger = New data  import, but may already be mapped by hand
way names are in both, but do not match location = Improved data  Compare
old tiger with OSM tiger tagged data
   -If old tiger and OSM match unedited, replace with new
   -If the way was deleted or edited in OSM, discard the new tiger data in
favor of the had edited.



-- 
Dale Puch
___
Talk-us mailing list
Talk-us@openstreetmap.org
http://lists.openstreetmap.org/listinfo/talk-us