2012-09-21 Lester Caine
<<
What I have been asking is how we can manage on-going imports of a
dataset that is being updated regularly. This is probably on 'off-line'
function, and could well be managed by the 'local chapter' on their own
computers. This is the 'process' I'm looking to be developed, so that
the raw import data is held in a format that later imports can be
compared against, and only differences then get further procession.
Breaking this process down into provinces, and importing the
pre-processed RAW data via an import account gives us a clean base which
mappers can then work against and improve the data ... and changes to
the 'imported' data would then be mirrored back to the staging process.
Seeing that an element is version 1 by the import user immediately tells
you that it may need additional local information adding ( we need to
be able to see who last edited an object! ). Where the import HAS nice
unique object identifiers things are a lot easier, but raw vector data
like the French import, and I think the Spanish data you are talking
about CAN still be 'diffed' against earlier imports, and result in
perhaps new data that can simply be imported, or perhaps an overlay that
identifies conflicts that need a human eye. Isn't it better to spend
time working out a GOOD way of using the data going forward rather than
having to manually merge the whole lot again in a couple of years time
... and every couple of years.
>>
In Canada, Natural Ressources Canada, the national mapping agency is
collaborating with OSM, producing OSM import files from is topographic database
Canvec. The OSM collaborators are following a procedure to carefully integrate
this data into OSM.
NRCan compared recently Osm and Canvec data for planning road network update
field work for Canvec. They also provided this helpful information to the OSM
community with detected differences.
see http://lists.openstreetmap.org/pipermail/talk-ca/2012-July/004934.html
I think that this shows that even without an unique ID, it is possible to
develop monitoring tools of imports. The fixme attribute is used to monitor
differences between the two databases. The Fixme Highlight Warnings style, in
JOSM, offers the possibility to monitor database discrepancies.
Pierre
>________________________________
> De : Lester Caine <[email protected]>
>À : OSM <[email protected]>
>Envoyé le : Vendredi 21 septembre 2012 17h33
>Objet : Re: [OSM-talk] Import guidelines proposal update
>
>andrzej zaborowski wrote:
>> Well, this time a
>> single import account has been registered per province with a single
>> person coordinating the (potential) imports in each province. The
>> assignments have been documented on the wiki. This is better but the
>> account names are still not directly linked with real people, and the
>> division by provinces is artificial because the data was supposed to
>> be uploaded by users only for the areas they know personally, which
>> may be on village level for example.
>
>To my eyes that provides a perfect base to work from, but if you have not been
>following the thread ...
>
>What I have been asking is how we can manage on-going imports of a dataset
>that is being updated regularly. This is probably on 'off-line' function, and
>could well be managed by the 'local chapter' on their own computers. This is
>the 'process' I'm looking to be developed, so that the raw import data is held
>in a format that later imports can be compared against, and only differences
>then get further procession. Breaking this process down into provinces, and
>importing the pre-processed RAW data via an import account gives us a clean
>base which mappers can then work against and improve the data ... and changes
>to the 'imported' data would then be mirrored back to the staging process.
>Seeing that an element is version 1 by the import user immediately tells you
>that it may need additional local information adding ( we need to be able to
>see who last edited an object! ). Where the import HAS nice unique object
>identifiers things are a lot easier, but raw
vector data like the French import, and I think the Spanish data you are
talking about CAN still be 'diffed' against earlier imports, and result in
perhaps new data that can simply be imported, or perhaps an overlay that
identifies conflicts that need a human eye. Isn't it better to spend time
working out a GOOD way of using the data going forward rather than having to
manually merge the whole lot again in a couple of years time ... and every
couple of years.
>
>-- Lester Caine - G8HFL
>-----------------------------
>Contact - http://lsces.co.uk/wiki/?page=contact
>L.S.Caine Electronic Services - http://lsces.co.uk
>EnquirySolve - http://enquirysolve.com/
>Model Engineers Digital Workshop - http://medw.co.uk
>Rainbow Digital Media - http://rainbowdigitalmedia.co.uk
>
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