[NUUG kart] Importing GNS data for Svalbard
Dag Bjerkeli
dag at jodalin.org
Tue Oct 7 22:13:52 CEST 2008
Gustav Foseid said the following on 07. okt. 2008 12:24:
>
>
> 2008/10/6 Mike Collinson <mike at ayeltd.biz <mailto:mike at ayeltd.biz>>
>
> Gustav, thank you for your kind feedback. All gone now except
> island names. May I ask about your experiences with quality? Was
> the problem just positional accuracy or did you find substantial
> errors in the names themselves?
>
>
> The main problem was positional accuracy, combined with the large
> number of small (close to irrelevant) place names. For many of the
> names we had knowledge, or could easily check, most names were misplaced.
>
> When we combined misplaced names, with the fact that many names were
> for very small places like farms, rocks and houses, they were of
> little or no use. You would need very detailed knowledge to be able to
> correct these names. I looked at the farm names around where I grew
> up, and had not heard about half of the names. Trying to correct the
> position, or even verify that the name was in fact still in use, would
> be impossible. Another example was a rather small area off the coast
> of Troms, where around 60 named rocks would have to be verified.
>
> For administrative names (kommuner), the names in GNS was old and was
> no longer correct. Other names also had archaic spelling.
>
> So, we basically ended up with a map where large areas were filled
> with names we knew were wrong, but with no way of correcting. Keep in
> mind, that we are acouple of handfulls of mappers, and the GNS file
> for Norway contains 84.000 names. That is approximately 10.000 names
> for each mapper to verify.
>
> Our conclusion is that importing the GNS data would ruin OpenStreetMap
> as a source of reliable geographic information in Norway.
>
> For Svalbard, the data looks more accurate. At least there are a
> number of digits in the latitude and longtitude, but also here the
> data suffers from unknown quality. There are also a few examples of
> the same name being given in different languages or spellings (the
> worst example I found is South Cape Islands, Syd Cap Æerna,
> Sydkapholman, Sydkapøerne, Sørholmen, Sørkapholmane, Sørkappholmane
> and Sørkapøyane, which seem to be the same islands). I wish we had
> known more about what sources are used to collect these data.
>
I had a quick look at the data for Bjørnøya, south of Svalbard. Most of
the names there were placed in a clear grid.
With the disclaimer of not knowing the locality of Bjørnøya well, this
did not look correct.
Regards
Dag
More information about the kart
mailing list