[Talk-ca] Problem with overpasses in NB??

Paul Norman penorman at mac.com
Tue Dec 3 00:28:01 UTC 2013

> From: Daniel Begin [mailto:jfd553 at hotmail.com]
> Sent: Monday, December 02, 2013 1:34 PM
> To: 'Richard Weait'; 'Connors, Bernie (SNB)'
> Cc: 'Talk-CA OpenStreetMap'
> Subject: Re: [Talk-ca] Problem with overpasses in NB??
> Provinces provide roads to NRCan that simply package it for GeoBase and
> Canvec. I might be wrong but I am on the impression that some provinces
> (not all) create vertices at intersections (2D) and do not consider the
> elevation (3D). When converting to OSM, duplicated vertices (one on each
> road) are merged in one node.

The problem is often one of formats. Shapefiles are often used to 
interchange this data, but shapefiles do not have topology. A common 
toolchain used for getting data from an ESRI-based server to shapefiles
results in files that say that wherever two features cross they join. 

This is the type of mistake that someone doing an import needs to catch
and fix before uploading. The fastest fix I've found in JOSM is to merge the

two bridge ways, merge the two under-bridge ways, and delete the node where
they intersect.

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