[Talk-GB] Admin Boundaries and OS OpenData BoundaryLine

Steve Brook srbrook at tiscali.co.uk
Tue May 29 21:34:15 BST 2012


Hi

Having done the import for the all of the Worcestershire parishes I will add
my views:

It should only be attempted by an experienced mapper who is familiar with
revert and other advanced techniques and can follow the guidelines on the
wiki. The potential to break something is very great, so I would question
making converted data available. Any conversion needs to build the relations
so use something like 'ogr2osm' to create .osm files - a conversion to GPX
will not do this.
Adding data to the map should not be done as a bulk import as there is a lot
of existing data - some imported and some traced from old map sources. Any
data you import needs to be integrated with existing data. Every boundary
will be shared between at least 2 relations and often many more.

The 'ogr2osm' conversion produced way segments that had a common shared
boundary with another parishes and also produced all the parish level
relations. I then just had to give them the right tags - it's much better to
get them right in the editor before upload than to have to correct them
later. Where parish boundaries were also district, county or region
boundaries I elevated the admin level before the import as it made the
filtering during the subsequent tidy up process easier. I also created
temporary relations for the county level boundaries before import to assist
with the later tidy up stage. Some lines on the perimeter of my data needed
to be cut where at the 3 county intersections. To do this I need to go back
to the original data to find the correct node to use. This was the main
reason why I chose to do the whole county in one go to minimise subsequent
work at the edges of the area I worked on.

I was lucky in Worcestershire as very few parish boundaries were present and
they were fairly easy to sort out by deleting those that only had boundary
tags and removing boundary tags from shared ways. 
I made a note of the numbers of all the existing boundary relations in the
area before I started work so I could update them with my new data. Where my
import matched some one else's import of the district boundary data I
usually kept the earlier work but split it into parish segments. The work
took many evening and late nights to complete.

If anyone wants more specific advice I am willing to provide it - just send
me an email.

Steve





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