[Talk-ca] Question about NIDs

Michel Gilbert michcasa at gmail.com
Wed Jan 21 12:28:52 GMT 2009

2009/1/20 James Ewen <ve6srv at gmail.com>

> On Tue, Jan 20, 2009 at 6:01 PM,  <michcasa at gmail.com> wrote:
> > It is not a simple issue. I see 2 options: the first one is to align the
> osm
> > geometry with the nrn-geobase geometry (or the opposite), then add the
> NIDs.
> > At this stage, I wonder if we should take Geobase geometry and join the
> osm
> > attributes. The second option is to use NIDs only for the nrn-geobase
> > imported in osm.
> I'm kind of stuck, and I'm not sure where to go from here.
> I have invested quite a bit of time and effort collecting, importing,
> and converting GPS tracks in Fort McMurray. Steve's GeoBase import
> script has done a very good job adding GeoBase data all around my data
> that I had already put into the OSM database.
> Now I need to spend time making the OSM and GeoBase data integrate
> together. I can add nodes that correspond to GeoBase nodes, and make
> my OSM ways connect to these points. I can attempt to make all of my
> ways correspond to GeoBase data, but that is a lot of work, especially
> trying to put all the attributes onto each and every one of these
> nodes and ways.

Your approach is the option 2 that I have mentioned. My favorite one too :
import nrn-geobase to complete exsiting osm then integrate it to existing
osm. The option 1 is my view if we wanted to have Geobase NID to existing

> What I would like to do, is be able to delete all of my OSM ways, and
> replace them with the GeoBase data. From there I would then use the
> GPX tracks that I have collected as a basis to modify the GeoBase
> data, so that it represents the real world data more accurately.
> It just seems to me that my time and efforts would be better invested
> by making minor modifications to the GeoBase data to align with my
> observations rather than attempting to make major modifications to my
> OSM data to align with the GeoBase data.
> Don't get me wrong, the GeoBase imported data in the Fort McMurray
> area is a good thing in my opinion. I also agree that the GeoBase
> update should not automatically overwrite user entered OSM data. What
> I am looking for is a way to be able to manually replace my existing
> OSM data with GeoBase data, but only at a specific user request, be it
> mine or someone else working in an area of their concern.

I noticed the same kind of examples. Sometimes, osm ways are not accurate or
badly captured. RoadMatcher does not work well for these cases. So to detect
them you have to do it manually and change them by nrn-geobase data. We
can't make the whole country like that. It makes the job harder but it price
to pay to keep existing data.

> Here's another example where I can see being able to manually remove
> old OSM data, and replacing it with GeoBase data. Most of the primary
> highway grid that exists in Alberta was traced from Landsat data, if
> I'm not mistaken. Whatever the source, the existing road data is of
> very poor accuracy.  Steve's road matcher is going to have a horrid
> time trying to match the GeoBase roads against the existing OSM roads
> which can be upwards of 1/2 a mile out of place. I doubt that I would
> find anyone that object to removing the crude existing OSM data in
> favour of the GeoBase data.
> An easy solution would be to delete all the crude highway data, and
> then run Steve's script against a blank slate. However, this means
> that someone will have to go through the OSM map before running the
> script to remove the crude data.
> I have tracked a number of major highways across Alberta, into BC, and
> also Saskatchewan and used that to replace the crude older highway
> data. Steve's roadmatcher script will probably have an easier time
> matching to those ways, but that still leaves thousands of miles of
> highway that will need to be manually stitched to the GeoBase data.
> Again, I think it would be much faster to modify the GeoBase data to
> match the GPX tracks if need be, rather than manually match the OSM
> ways against the GeoBase data.
> Anyone else have any observations or opinions?
> James
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