[Talk-ca] GeoBase and OpenStreetMap

Dan Putler dan.putler at sauder.ubc.ca
Mon Dec 15 19:01:13 GMT 2008


Hi Mike,

Like you, I'm new to this list. I'm actually a member of the PAGC
project steering committee. PAGC (www.pagcgeo.org) is an open source
postal address geocoder. While doing this work we have found that a
major challenge is publicly available road network data. Historically,
we have been more focused on the Statistics Canada RNFs (and the US
TIGER data) since they were publicly earlier, and had address range data
and street names that allowed for interpolation based geocoding. As I'm
sure you know, in the current NRN only road segments in Alberta, Nova
Scotia, and the Yukon have street names _and_ address ranges, and BC
road segments have street names but no address ranges. In addition these
four jurisdictions have local area identifiers (municipality in the case
of the NRN, as opposed to the US five digit Zip code in TIGER) for the
road segments, which is not present in the StatsCan RNFs). My real
interest is whether or not all the provinces and territories will
eventually have street names, address ranges, and local area
identifiers, and if the answer is "yes", whether there is any sort of
time line in terms of the release of this information? As things
currently stand at this moment, if you are working with Alberta, Nova
Scotia, and the Yukon, the NRN is the right choice; in BC whether you
use the NRN or the StatsCan RNF data is a tough call; and for any other
province or territory you probably want to use the StatsCan RNF.

The other thing that may be useful for you to know is that this effort
is likely to have been coloured by the experience of uploading the US
TIGER data into OSM. TIGER data has real positional accuracy issues, and
people have done a lot of work re-doing the road segments.
Unfortunately, in doing this, most people who are mapping have made no
effort to maintain any of the TIGER attributes (keeping the TLID would
have been really useful). Moreover, many of the attributes (like the
address ranges and Zip code information) were never included in the
original upload of the data. In addition, the ways (road segments) that
people have created in OSM often contain multiple block faces. As a
result, the OSM data has lost valuable attribute information that was
contained in the original TIGER data ("fixing" this problem is something
we are exploring, but will not be easy), and it would be unfortunate if
the same thing happened in the upload of NRN data into OSM.

Dan

On Thu, 2008-12-11 at 15:02 -0500, Mepham, Michael wrote:
> Before I get on with my comments let me introduce myself to the group.
> My name is Mike Mepham and I am a member of the GeoBase Steering
> Committee.  In fact, I was in on the founding of GeoBase in 2000/2001
> and have been active with it ever since.  I have 19+ years with
> Saskatchewan’s geomatics agencies and am currently on secondment to
> the federal government tasked with helping to continue and enhance the
> cooperative geomatics programs between the 14 governments in Canada
> (federal, 10 provincial, and 3 territorial).  A couple of things I am
> not – I am not an employee of the Government of Canada although they
> provide me with my work facilities.  I am still employed by one of the
> provincial governments.  Also I am not the technical go to guy.  
> 
> I have two objectives with this note – The first is to clarify exactly
> what GeoBase is and is not.  Hopefully I can help clear up some of the
> confusion I have noticed in some in the postings to this discussion
> group.  The second is to enter into a discussion about what this group
> is trying to do, why, and how we can work together or at least not get
> in each others way.  
> 
> What is GeoBase?
> 
> GeoBase is a collaborative partnership of the federal, provincial, and
> territorial governments working to wards a vision of “Fundamental
> geographic data of choice for Canada – collected once, maintained and
> available without restrictions”.  The idea is to ensure that any data
> collection only takes place once and the results shared.  Also, every
> effort is made to ensure that the agency responsible for the content
> of the mapping is the agency that is “closest” to the items being
> mapped.  For example, many of the municipal roads in GeoBase are
> mapped by the municipality itself who provide the data to the province
> who add it to the provincial roads mapped by their department of
> transportation and then the whole is submitted to GeoBase for
> inclusion in the portal.
> 
> So please do not refer to GeoBase data as federal data.  While some of
> it is federally sourced most of it is municipally, territorially, or
> provincially sourced and made available through the collaborative
> partnership. 
> 
> There are several attributes (not data base attributes) that the data
> must have to be included in GeoBase.  These include that it is
> expected to be authoritative, maintained, freely available, etc.  For
> full details on this and more on how the partnership works I strongly
> recommend reading the GeoBase Principles, Policies, and Procedures
> (PPP) document.  It will give you a better understanding of the animal
> you are dealing with.
> 
> Some Questions
> 
> Let me start by making it clear that I am asking these questions to
> help my understanding.  Nothing here is intended to stop, or delay the
> groups progress in loading the GeoBase information into the OSM.  
> 
> My first question has to be “Why are you doing this?”.  I have spent
> some time looking through the OSM web site and I understand the
> rational for building street maps where none exist or at least are not
> generally available but that is not the case here.  I know of at least
> two other complete downloads of the GeoBase data for redistribution
> but still do not fully understand the reasons for replication /
> duplication.  
> 
> Secondly – How does this group expect maintenance to work?  When the
> data suppliers pass updates to the GeoBase portal team and those
> updates are made available then GeoBase and OSM will be out of sync.
> What are the expectations on how or when they will be brought back
> into sync?
> 
> And finally, for now, Are there any comments or questions you would
> like to direct to the GeoBase Steering Committee?  We don’t always
> hear back from those who are using the GeoBase portal and it’s data
> but want to.  Please speak up if you have something to say to us.
> 
> In closing I would like to suggest that you also check out the video
> at YouTube that shows some of the research we have been involved with
> looking at interoperability of diverse geomatics data bases.  The
> video is at http://www.youtube.com/watch?v=YIZLc_qHYZc in English and
> http://www.youtube.com/watch?v=BXvUqWVtjQo in French.
> 
> Thanks for your time.
> 
>  
> 
> Mike Mepham
> 
> Federal/Provincial/Territorial Liaison
> 
> GeoConnections Program
> 
> Natural Resources Canada
> 
>  
> 
> E-Mail:  MMepham at NRCan.gc.ca 
> 
> 
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-- 
Dan Putler
Sauder School of Business
University of British Columbia





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