[Talk-ca] CanVec Reverts

Thu Sep 1 15:35:25 UTC 2016

I'm usually just a lurker on these lists but this has dragged me out of my
cave.

Michael,

I'm glad you care about the quality of the map, I do too.  I welcome you to
take an constructive approach to working with these problems.  Canada has
an area of 9,984,670 square kilometers with a population density of only
8.8.  That presents us with challenges that wouldn't apply to a country
with an area of 357,022 square kilometers and a population density of
593.  Rather
than handing out an ultimatum to the Canadian mapping community how about
you work with us?  We share your concerns in regards to data quality but
your unilateral reversion of commits without communication or cooperation
is damaging to the map.

I find your comment "if it has not been touched for a few weeks" comment to
be insulting and it shows a complete lack of understanding of the realities
on the ground.  I'm personally working at improving the map in my area
(County of Vermilion River, Alberta, Canada) and you are more than welcome
to constructively help. However, just because I haven't touched something
for a couple of weeks doesn't mean I've forgotten about it.  It means I was
on holidays or got busy with other things in the office.

Have you ever tried importing data using JOSM?  I've spent hours poring
over a few square miles of countryside and trying to get everything cleaned
up and merged.  Then, when I actually import, the data gets split into much
smaller sizes.  Or maybe I get some of it imported and then have to fix a
bug I missed in something else.  To somebody like you it looks like I just
dumped a bunch of data in when in reality I've been picking away at it for
a few days.

Darren Wiebe

On Thu, Sep 1, 2016 at 8:49 AM, Sam Dyck <samueldyck at gmail.com> wrote:

> Micheal
>
> Thanks for contacting us. I must object strongly to your use of the Worst
> of OSM example and generally assumption that the data is broken if it
> doesn't line up. I checked multiple commercial imagery providers before I
> found a digitalglobe image that covered the area during the summer. There
> is a large patch of sand between the vegetation-filled area and the coast.
> As for the boundary, that comes from another official source, I think it is
> supposed to be spaced off of the coastline, though I don't remember exactly
> how they calculated it, we would likely need a constitutional change to
> make it line up with the coast. Just because things don't match up does not
> mean that the data is wrong. Nature doesn't always translate into nice,
> clean maps.
>
> Sam
>
> -----Original Message-----
> From: Michael Reichert [mailto:nakaner at gmx.net]
> Sent: Thursday, 1 September, 2016 01:39
> To: talk-ca at openstreetmap.org
> Subject: [Talk-ca] CanVec Reverts
>
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA256
>
> Hi,
>
> unfortunately posting via Gmane does not seem to work (the website is down
> but NNTP still works), that's why I have to start a new thread. :-(
>
> Am Tue, 30 Aug 2016 21:41:21 -0500 schrieb Sam Dyck:
> > After reading through the changeset discussion, I discovered that one
> > of my imports in Northern Manitoba made Worst of OSM.
> > (http://worstofosm.tumblr.com/post/22180046353/dear-
> > openstreetmap-isnt-it-strange-how-the). As someone who spends a some
> > time amount of time in some of relatively unpopulated areas of Canada
> > and makes an effort to check the quality of Canvec data (which is
> > usually pretty good), I do agree that it is impossible to do
> > everything to the same level of quality that we would provide in
> > Toronto or Timmins or even small prairie towns.
>
> First of all, it is ok that an import takes a few years and therefore
> creates ugly green rectancles on the map. If an import is "unavoidable"
> :-), a manual import is the best thing that can be happen. But if someone
> uploads a changeset without a manual review beforehand, he counteracts the
> aim of a manual import: addind good data to OpenStreetMap. That's what I am
> mainly fighting against. If a users uploads much more than 100 objects per
> minute [1], you can be sure that he has not done any manual review. A
> manual review by myself confirmed this these. I am fighting against such
> changesets/users.
>
> A good imports must be reviewed *before* it is being uploaded. The review
> contains:
> - - Run JOSM validator, fix all warnings and errors. This includes all
> warnings regarding validity of areas. (you can argue if all warnings about
> "deprecated" tagging have to be fixed)
> - - Compare the data with available imagery. Is the forest really a forest
> or is another tag more appropiate? Right-click on a Bing tile at JOSM and
> have a look how old/recent the imagery is.
> - - Check if CanVec data fits to itself.
> http://worstofosm.tumblr.com/post/22180046353/dear-openstreetmap-isnt-
> it-strange-how-the
> <http://worstofosm.tumblr.com/post/22180046353/dear-openstreetmap-isnt-it-strange-how-the>
> - - Check if there has been any other data before. If yes, adapt the
> either the CanVec data or the old data.
> https://wiki.openstreetmap.org/wiki/File:Import-Fails-Powerlines-Not-Ins
> ide-Cutting.png
> <https://wiki.openstreetmap.org/wiki/File:Import-Fails-Powerlines-Not-Inside-Cutting.png>
> https://www.openstreetmap.org/way/439631732
> - - Ways should not overlap with other ways if it is not necessary. The
> outer ring of a lake should also be inner member of the forest
> multipolygon. Maybe the program which created the OSM files should be
> imprved?
> - - Keep the history.
> https://wiki.openstreetmap.org/wiki/Good_practice#Keep_the_history
>
> If a tile has been imported without being checked manually and no
> post-upload fixes have been done (i.e. upload without any checks), I will
> not shrink from reverting it. If a tile has been uploaded to OSM without a
> review and if it has not been fixed within a month, it is worthless and can
> easily be reimported at a later time if someone has the time to check and
> fix it.
>
> For the future, I will abstain from reverting changesets which have been
> imported before September 1, 2016 and whose users are currently doing the
> fixes that should already have been done. But if I come across an imported
> tile of low quality which has not been touched for a few weeks and is full
> of errors, it is just a question of time until it is reverte d.
>
> Best regards
>
> Michael
>
> [1] I had a look on a few of my changesets which added a large number of
> buildings to OSM. The fastest changeset contained about 60 objects per
> minute and was full of missing buildings as I later detected while
> collecting the housenumbers and usage of the buildings.
>
>
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