[Talk-ca] Own experience with Geobase

Michel Gilbert michcasa at gmail.com
Wed Nov 19 00:03:05 GMT 2008

Hi all,

I am very glad to read Richard's announcement. I experimented the conversion
of the NRN (Road Network) to Open Street Map in September and October. Here
some starting observations:

- Keep the original OSM data.I did not use Geobase data when OSM exist. In
general the matching to identify common geometries is good. However, some
manual edition is required when the representation is different in Geobase
and OSM (motorway as 1 or 2 separate ways for example).

- The OSM ways must be altered (insert nodes) to assure connectivity between
the existing OSM ways and new ways that came from Geobase segments.

- New ways that came from Geobase are tagged as followed:

  <way id="-9767" action="modify" visible="true" user="pythagore">

    <nd ref="-4871"/>

    <nd ref="-4870"/>

    <nd ref="-4869"/>

    <nd ref="-4868"/>

    <nd ref="-604"/>

    <tag k="created_by" v="JOSM"/>

    <tag k="highway" v="primary"/>

    <tag k="nat_ref" v="7a8ee7aeb196462088c1fad7b7e83842"/>

    <tag k="source" v="geobase"/>

    <tag k="lanes" v="2"/>

    <tag k="ref" v="132"/>

    <tag k="name" v="Rue St-Joseph"


·         The key value for highway came from the Geobase attribute

·         The key value for source is set to 'geobase' to keep the origin of
the data (license issue)

·         The key value for nat_ref is the Geobase NID attribute. I kept
this ID to link the geobase Road segments at OSM ways. It will be easier, in
the future, to obtain the road/street names when they will be available.

·         The key value for lanes is the Geobase attribute NBRLANES.

·         The key value for ref is the Geobase attributes RTNUMBER1 …

·         The key value for name is the Geobase attribute R_STNAME_C

- The Geobase segment geometry (ways segmented at each intersection) becomes
OSM ways. Keeping the original geometry assure the link between Geobase/OSM
for further updates using the nat_ref. However, in OSM, the rendering is not
nice because it repeats the street name and ref numbers.

- I made some tests:

   - Rimouski
   - Kamloops
   - Gaspesie

Thanks again Richard for your effort. I would like to contribute to put
Canada on OSM.

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