match gps data to tiger/line

[Stephen Woodbridge]

Kurt Kuo wrote:
> Hi list,
> I have some vehicle position data and would like to link them together 
> in order to draw it trajectory. However, the trajectory segments do not 
> match tiger/line so well. Some of them offset pretty much. Is there a 
> way to make gps position data and the trajectory segments match 
> tiger/line better. Thanks in advance.
>  
> Kurt

That is just the data! Tiger is getting much better as the realign the 
data, so if you are not on a current version, I would suggest you update 
to the newer data.

You will find some data is aligned very well and some is not. If you are 
on Hawaii, that is in some local island projection and and tracks on 
east coastal roads will fall about 1500 east in the ocean :-0

The Census is realigning about 300-400 counties every 6 months and the 
data is very accurate in these counties, although I have found some 
strange roads that don't exist on the ground, because they were picked 
off of satellite imagery.

-Steve W.