[Imports] Galician protected areas

Martin Koppenhoefer dieterdreist at gmail.com
Sat Nov 14 10:37:30 UTC 2020


Am Sa., 14. Nov. 2020 um 11:18 Uhr schrieb Miguel Branco <
mgl.branco at gmail.com>:

> 1) Those areas require a previous conflate, yes. I've done so using JOSM
> and JOSM/conflation add-on for most of the areas. I indicate "yes, merged"
> in wiki tables to note if they’re conflated and are ready to upload. I have
> to edit some areas yet but when necessary I’ll use conflation too.
>
> 2) About the data of accuracy/positioning in relation to OSM data. When
> working with IET data (shapefiles), I did a double checkout: compare
> imports with mapas.xunta.gal/visores/basico/ (government official map
> viewer) and the official documents that parliament passed by to declare
> natural protected areas (In our case those are published in "Diario Oficial
> de Galicia – DOG", that contain their maps).
>


is the legally binding description of these areas in the attached maps, or
is it a textual description and the maps are there for mere illustrational
purpose, or is it about the sign delimited area on the ground? Which
nominal scale are the published maps? Are the areas signposted on the
ground?



> I saw no problem about protected areas' position: they fall in their
> provinces, councils, include or not some villages and so on. In fact,
> there’s some of them already mapped in osm that have some pitfalls. This
> import would correct those mistakes.
>


if you are sure that the mistakes are in OSM, am I right in guessing you
are planning to prefer the official dataset in any case over existing data
in OSM when there are differences?


About the detail too, yes, in some cases source data has too much detail.
> But a random reduction of it can mean including or not e.g. a small village
> or even a protected tree from a natural park. That’s why I think that we
> need to avoid data reduction here.
>


I am not sure which kind of "reduction"  you are speaking about, if it
could make the difference of a whole village being included or excluded I
am sure that it is not an acceptable level of reduction/tolerance. I would
rather see it the opposite way: not so unlikely that the official data has
already been reduced compared to the (usually very precise "internal"
official  data), before publishing it as open data, and there might be some
resulting details which could be seen as problematic on the micro level
(e.g. if a road or a waterway is part of the area or not, or maybe is after
the simplification half in half out, etc.) Also these areas will be
delimited by other features (roads, fields, settlements, waterways, etc.),
and ideally there boundaries in OSM should match with the representation of
these things in OSM (this means more consistency as matching the exact same
coordinates, which will be relating to official data. Hopefully these
differences are small anyway, but a few meters can already make the
difference whether a road or a stream is included or excluded, or is half
in half out.

Cheers
Martin
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