I will try to take this opportunity to address some of the issues raised over the last couple of weeks. First off though - I hope everybody had a good holiday and is starting out on a great new year.
GeoBase nodes I can confidently tell you that GeoBase will not be creating a nodes only data set for the use of OSM. We have our hands full enough completing and maintaining the existing data and adding new themes of data, including the hydrographic data. If the discussion concludes that nodes are desirable then the group will need to extract them themselves. As a side note - the general policy is not to perform customisation on the data for individual clients or client groups. Road Names and Addresses The objective is to have all the road names and address ranges for Canada in GeoBase. There are a couple of things that need to be understood in the scheduling of this. First is that adding this information requires the agreement of the 14 governments involved and in many cases agreements between the provincial and municipal governments for a province. We expect to have a schedule in a few months, as we work our way through the agreements. Secondly, the data does not exist in some areas or even provinces. Or it exists but is not available for free and unrestricted distribution. One of the principles of GeoBase is that coverage is to be national. We cannot just cherry pick the areas where data is easy but ignore the hard areas. Thirdly, accuracy is important. This data will not just be used for pizza delivery but also for emergency services delivery as well as by Statistics Canada and Elections Canada for delivery of their programs. One Segment vs. Two Segments A couple of posts have mentioned that for some reason the GeoBase data has two segments for the same road, or part of a road. The answer to that one is easy - there is a median or divider for that portion of the road. (Note that short medians are not modelled into the data.) Statistics Canada data In evaluating the use of the Statistics Canada data sets I suggest that you remember that they were developed for the specific purpose of census taking and electoral boundary development. These applications require far less positional accuracy than you may be expecting. Also, the update cycle is tied to the 5 year census cycle. OSM data vs. GeoBase data I note with interest the discussions about whether or not to "replace" existing OSM data with GeoBase data where the two coincide. The discussion seems to recognise two options - replace the OSM or leave out the GeoBase where there is duplication. I would like to suggest that there is a third alternative that I have seen only hinted at so far and that is to merge the two. Each data set has its own strengths and if they were to be merged based on the strengths a superior data set could result. OSM has attribution and linked data that exceeds what GeoBase has or was designed to hold. GeoBase has a positional accuracy that exceeds what most of the OSM data could achieve. It also has a set of basic attributes based on national definitions and standards. I realise that there is a reluctance to lose the valuable work of volunteers but the objective of the overall project must be kept in the forefront. And if I read the posts correctly the objective is still to be decided and agreed on. Maintenance It is our experience that creating a data set is the easier part of the project. Keeping the data current and correct is harder but paradoxically cheaper than the original mapping. Of the millions of kilometres of roads in Canada only a tiny percentage need to changed/added/deleted as part of maintenance. The challenge is identifying these roads. Any thoughts or suggestions from the members of this list would be welcome. We are always trying to find more economical methods for keeping the data current. Also - there has been some discussion about the need to re-load the OSM when there is a GeoBase update. I would point out that GeoBase has begun issuing change files that reflect only what has changed between two releases and that should simplify keeping the OSM current. Thanks Mike Mepham Federal/Provincial/Territorial Liaison GeoConnections Program Natural Resources Canada E-Mail: [email protected] <mailto:[email protected]> 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
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