On the CanVec question - The CanVec road network data is or will be identical to the GeoBase data. Right now CanVec is identical to GeoBase but prior to some of the GeoBase updates. The data flow is provinces to GeoBase to CanVec with processing / scheduling delays along the line. CanVec is updated every 6 months or so and given processing times could be as much as 12 months behind GeoBase.
The other difference to note is that the GeoBase data is continuous while the CanVec data is cut at the sheet edges. The CanVec data carries the GeoBase unique identifier on the road segments. When a segment is split at the sheet edge both pieces will carry the same GeoBase identifier so if you choose to use the CanVec data you might want to plan on merging segments with common GeoBase identifiers. (There is also a CanVec identifier which is unique to each segment piece so be careful about which you use.) A personal thought - Perhaps you could extract the list of GeoBase identifiers from a CanVec data set and then use that to select the GeoBase segment to add. It should be possible to deal with the duplicates fairly easily. The main issue would be what to do with any GeoBase segments left behind (these would be updates that have not made it to CanVec yet.) Similarly the GeoBase hydro data currently in production will replace the CanVec data once it is complete and the updates will be to GeoBase first, then promulgated through to CanVec. This is the intention with future GeoBase themes as well, as they are added. On the ID question - The ID on the GeoBase objects is a permanent ID. Attribute changes and positional updates (e.g. street re-alignments) will not cause the ID to change. Mike Mepham Federal/Provincial/Territorial Liaison GeoConnections Program Natural Resources Canada E-Mail: mmep...@nrcan.gc.ca Ottawa Regina Phone: (613) 992-8549 (306) 780-3634 Fax: (613) 947-2410 (306) 780-5191 Address: 06Ath Floor, Room. 646R 615 Booth Street Ottawa, ON Canada K1A 0E9 100 Central Park Place 2208 Scarth Street Regina, SK Canada S4P 2J6 ________________________________ From: samvekem...@gmail.com [mailto:samvekem...@gmail.com] On Behalf Of Sam Vekemans Sent: December 15, 2008 04:12 To: Mepham, Michael Cc: talk-ca@openstreetmap.org Subject: re: GeoBase and OpenStreetMap - welcome Hi, 1st off, thanks for joining in the group, i'm sure your help will be most valuable. I'll need a little bit (a couple days) to go over each of your points with a more formal response. The only thing I didn't see is the relationship with the CanVec data, (that I am currently exploring), making a chart showing the relation from this dataset to how we look at it in OpenStreetMap. .. matching the labels, with OpenStreetMap tags. For the import program to use. For now, thats my biggest question, as road and Hydro & Topo data are also available CanVec. The question/issue raised was about update frequency. Which one do we focus on? What is the other complete download of geobase data? I know that 1 of them from for the Ibycus topo. My guess would be OSGeo? And for dealing with updates? We are planning on making a program which is able to detect current points in the OSM database, which have the the same attributes, and place the GeoBase (NRCan) ID onto it, and where no OSM data exists, place this new GeoBase data onto it. (to talk-ca list: .. similar to how the renderer has a list of common elements which the program knows how to read (and then creates the maptile), the rest it avoids, or makes a note that there is an error and fills out a big report) Our biggest assumption would be that the NRCan ID that is placed on the data would not change, so that when more attributes are available ie. house numbers, these attributes can be added onto the OSM database, provided it doest aleady exist. So the program could essentially be run several times over, grabbing different datafiles, going through the whole list of NRCan to OSM common elements. (this way, different elements can be added at different times) ... so only when when people are ready to work with it. As there will be some manual adjusting, as tagging from both sides wont be perfect, and so this program will be updated as people find errors. (ps. a timestamp, the date the NRCan data was added would be on of the tags that the program would look at too, and perhaps the date of the original source also. As this is a good point of reference) Does this make sense? I know that it's technically possible to make such a program, it's just a matter of finding the right people out there who can make it work. :) I will get back to you after i had a chance to go over your message in further detail, so to answer all your questions. I'm sure others might also respond too. (as this is an open discussion group). Sam Vekemans Across Canada Trails
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