[Talk-GB] English administrative divisions cleanup/fixup

Feargal Hogan feargal at thehoganfamily.info
Sun Feb 15 14:19:34 GMT 2009


Hi

First post to the list.

I've been looking to get access to a set of polygons for the main English
administrative divisions. I'm not that concerned with the celtic regions for
the time being. This data <<IS>> available via ONS/OS but with licencing
restrictions. Better to use/create a free-to-use set, I thought.

Working on the basis that I needed to create it myself, I took the list of
schools at http://www.showusabetterway.co.uk/call/data.html#schools and
matched it against the NPE postcode data. It only managed to geocode about
5% of the schools, but it was enough for my next proof-of-concept step.
Using the data I was able to create voronoi cells for each Local Education
Authority (well each one that contained at least one postcode in the NPE
dataset).

These were not very accurate in most cases, but some data is better than
none.

My next step was to see if I could 'help' the voronoi analysis by excluding
the areas where there was already free boundary polygons available. This
took me back to OSM. So I extracted the boundary data for England using
something like
http://osmxapi.hypercube.telascience.org/api/0.5/*[boundary=administrative][
bbox=-4.65,50.1,2,55.4]
and had a good browse through it to see what I was getting. The
'free-tagging' nature of the OSM data (and this is not a criticism, just an
observation) means that it is difficult to quantify the quality of the data,
and also it is difficult to filter the dataset into something meaningful and
useful, at least for my purposes.

I figure that I am going to have to do a fair bit of clean-up on this data
before it is useful to me. What would be a real waste of time would be for
me to do all the cleanup, and then NOT reflect it back into the OSM dataset.
Whilst I have done quite a bit of interactive editing using potlatch and
josm, I haven't done any dataset uploads.

So my questions are:
1) How should I approach such a data cleanup operation? and
2) Are there any agreed data tagging standards for the UK or more
specifically for England?

Appreciate any comments or suggestions you might have.
Thks
Feargal Hogan





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