[Talk-us] TIGER Data in Wrong Place

[Paul Johnson]

Andrew Ayre wrote:
> Hi! When I load OSM data into my GPS unit using mkgmap for a place in 
> the UK then it is accurate. When I load OSM data for Tucson, Arizona 
> then it is off by perhaps 100ft.
> 
> I would like to make the maps for Tucson usable, so my questions are:
> 
>    - how do I tell where this problem begins and ends?

Get on the road, create a trace of where you want to check.  Visually
compare map to trace.

>    - how do I fix it?

JOSM usually works well.

> I don't have the time to manually move everything, so there must be some 
> kind of automated solution? Does this problem exist for the whole of the 
> US? Is it well understood?

No automated solution.  Problem exists to varying degrees nationwide.
It's well understood that the TIGER data has a giant margin of error.

> Also if you look at the diagonal (NW-SE) part of the Arizona-Mexico 
> border there are streets in the US that appear in Mexico - the whole 
> border area appears to be a mess. How do I know what needs to be done to 
> fix this? The error looks larger than 100ft.

This will probably require some serious manual intervention.  If you
know where the border really is in that area, you should probably fix it.

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