[Open-data-census] Dataset Definitons

[Rufus Pollock]

All good points Andrew and I think your proposed definition is a definite
improvement and we've just updated the database to reflect it.

Rufus


On 3 October 2013 19:12, Andrew Stott <andrew.stott at dirdigeng.com> wrote:

> Rufus****
>
> ** **
>
> Thanks for your post
> http://lists.okfn.org/pipermail/open-data-census/2013-October/000219.html*
> ***
>
> ** **
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> However I’d like to push back *strongly* on the proposed change to the
> definition of “postcodes/zipcodes and their corresponding geolocations”
> and, in particular, defining geolocations as “boundaries/areas
> corresponding to those postcodes”****
>
> ** **
>
> “boundaries” can be very demanding – it requires the trace of the
> boundaries, which may or not be recognised administrative boundaries.  In
> some cases the boundaries overlap because of how postcodes are defined
> (they generally reflect collections of delivery points linked to delivery
> offices and not recognised administrative boundaries – see for instance the
> complexities in the US http://en.wikipedia.org/wiki/ZIP_code  It also may
> involve more than one government agency to put the data together.****
>
> ** **
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> What is meant by “areas” – is this a geospatial bounding area (ie a
> rectangle) or the *name* of the town to which the postal code relates -
> which makes sense in Australia and, to some extent, the US, but which means
> a data loss in countries such as the UK, Canada and the Netherlands which
> have finer grained postal codes.  And turning a postal code into the name
> of a town is not necessarily very useful.  A number of postcode databases
> already identified in the Census give the name of the street in which the
> postcode is.****
>
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>
> In my experience the two standard use case of a postcode database and
> geolocations which I have seen is as follows:****
>
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> (1) I have a table of data in which each row has an attribute which is or
> contains a postcode (perhaps as part of a postal address) – for instance
> points of interest, crimes, houses for sale.  I want to plot each row on a
> map.  So I need to translate the postcode into a lat/long.  A database of
> postcodes and their lat/long (or the eastings and northings in the national
> coordinate system, which can be converted to lat/longs by well known
> formulae) allows me to do that.****
>
> ** **
>
> (2) I have an application in which I want the user gives a location by
> postcode as a shorthand for the address, and I want to use that location to
> describe the issue or to find other relevant locations.  The classic
> examples are http://www.fixmystreet.com/  or a “where is my nearest?”
> application (cf http://maps.camden.gov.uk/ ) including the famous toilet
> finders.  Again I need to be able to convert the postcode into a lat/long
> or equivalent, and then use it to locate the problem or measure distances
> to other similarly coded locations.****
>
> ** **
>
> In both these use cases the key requirement is that the database should be
> of postcodes and their corresponding geospatial co-ordinates (in lat/long
> or a system convertible to lat/long).  Your proposed definition does not
> ensure that.****
>
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> So I would instead make obtaining a lat/long as the key requirement.  I
> would also allow cases where the corresponding location information (eg
> town name) could be converted to lat/long through the use of other open
> data (eg an open address register or gazetteer with lat/longs) ****
>
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>
> So I propose an alternative definition:****
>
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> “a database of postcodes/zipcodes and a corresponding geospatial locations
> in terms of a latitude and a longitude (or similar co-ordinates in an
> openly published national co-ordinate system).  A database which gives a
> location in terms of the name of a town or a street without lat/long
> co-ordinates is not acceptable unless the name of the town or street can be
> further converted to a latitude and longitude by means of other open data
> (eg an open gazetteer with latitude and longitude attributes).”****
>
> ** **
>
> Regards****
>
> ** **
>
> Andrew****
>



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Rufus Pollock

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