[Talk-ca] Question about NIDs

James Ewen ve6srv at gmail.com
Wed Jan 21 04:04:39 GMT 2009


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.

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.

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
VE6SRV




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