[Imports] Vermont Town boundaries from VCGI

Paul Norman penorman at mac.com
Thu Aug 9 07:22:44 BST 2012


> From: Andrew Guertin [mailto:andrew.guertin at uvm.edu]
> Subject: Re: [Imports] Vermont Town boundaries from VCGI
> 
> Interestingly, on the US-
> Canada border, most of the nodes seem to be exactly the same--OSM has
> them marked with survey point reference numbers, so this would make
> sense--but shifted a few centimeters. Probably something to do with
> projections. 

The Canada-US border is defined by the IBC which considers their list of
survey points and turning points to be public domain so me and another user
have done some work at using their positions to update the OSM data. Their
turning points are defined and accurate to within the limits of their
NAD27->NAD83 conversion, plus the error between NAD83 and WGS84 which is
minimal. Their survey points are accurate within the limits of good survey
equipment.

I don't know if the other user has gotten to where you're looking at, but if
they have that could explain the closeness and reference numbers.

And I believe both of us are Canadian, so we can call it the Canada-US
border. :)




More information about the Imports mailing list