[Talk-us] Fresno castradal imports

Martijn van Exel m at rtijn.org
Thu Apr 26 15:39:38 BST 2012


Hi,

On Thu, Apr 26, 2012 at 12:54 AM, Paul Norman <penorman at mac.com> wrote:

> I happened across an import of Fresno castradal data from mid-2010 in the
> Fresno area. http://www.openstreetmap.org/?lat=36.77&lon=-119.81&zoom=15is
> the general area but I haven't fully explored the extents. For a view of
> the
> data, see http://maps.paulnorman.ca/imports/review/fresno.png
>
> A few observations:

> 1. It is castradal data. The consensus is against dumping castradal data
> into OSM.
>

I am not aware of such a consensus - consensus among who? Is it documented?
I would expect such a consensus to appear in the Import Guidelines but it
doesn't.
Or do you mean there's a consensus against dumping data into OSM in
general? If by 'dumping' you mean 'importing without consulting the
community and without giving proper thought to attribute mapping and
generalization / normalization of geometries' then yes, I'd say there's a
consensus against doing that. I don't see why we would not cherry-pick
useful and good cadastral data for import into OSM, however. It may be our
only source of things like building outlines (are those generally in
cadastral data in the US?) or address data in many parts.

I don't mean to be nitpicking here, I just want to clarify what this
consensus actually is so people looking for guidance on importing in the
future can be more fully informed.

[...]

> 8. There are duplicate nodes where data was imported on top of other data.
> For example, http://www.openstreetmap.org/browse/node/768314177
> http://www.openstreetmap.org/browse/node/767799968
> http://www.openstreetmap.org/browse/node/767770150
>
> With all of these problems I cannot think of any ways to fix the problems
> short of reverting the import. The tagging problems could be fixed by a
> script but the inherent problems of castradal data cannot be fixed without
> essentially deleting most of the import anyways.
>

Are these problems inherent of cadastral data in general, of this dataset
in particular, or of the way this import was conducted?

>
> I propose to delete unmodified objects from this import. I will attempt to
> preserve areas like schools and fix them if possible. It should be possible
> to keep most of them but I won't be able to be sure until I get into the
> removal.
>

 The list of issues is long enough and the issues serious enough to warrant
a revert.
What I'm missing from this list is the issue I consider to be the most
serious, which is that this user apparently has not consulted with anyone
in the community about this import. Or has he/she?

-- 
martijn van exel
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