[Openstreetmap] Re: freeing the postcode database

[Daniel Haran]

[oops. Didn't hit reply all the first time]

Great project!

Would you consider collecting street address data at the same time?

I've been thinking about Canadian postal codes for a while now, and
have a few ideas that may apply
in other contexts. Please bear with me while I try to explain this...

The geocodes are not crown copyright- although their list is.
I'll try to give some background on this, and a couple ways I think we
could bootstrap a free
geo-database for Canada- free of copyright.

Postal codes here have a well-documented internal structure.

First letter:
A -> Newfoundland and Labrador
B -> Nova Scotia
E -> Prince Edward Island
etc...

Canada Post has a pdf map, with smaller maps down to the FSA (Forward
Sortation Area, or the 3 first
characters of the code, out of 6). The map is copyrighted.

The neat thing is that all the postal codes starting with "B2" are in
the same polygon, and "B2Y", "B2X"
are similarly subsets of "B2".

The only reasonnably affordable data I could obtain was copyrighted,
and only accurate to the FSA in
urban areas. Unique postal codes were correlated to rural communities,
so those were surprisingly
more accurate.

With very few data points in the cities, it should be possible to
build a free alternative to the
commercial offerings. (A free geocoding web-service would be a neat
way to get developpers
to submit more data in an automated way, although not geocoded it
would be useful to correlate.)

Some street names may be found by correlating all this data. Few
streets span more than one FSA,
and many span more than one FSA+1 or FSA+2, so we may be able to make
educated "guesses" about
street names in an automatic fashion. Also, given a FSA+1/2 shape, an
address/postal code pair would
give us an address point on the street vector, between the two points
where it intersects
with the polygon- helping us geocode addresses.

Of course, that all requires some base street data, and enough
address+postal code+lat/long points to
start correlating and we're not that far along yet in Canada :(

Daniel

On 8/8/05, Petter Reinholdtsen <pere at hungry.com> wrote:
> 
> [Steve Coast]
> > How about a drop down box to choose country? Sound good?
> 
> It should be enough for now, but I suspect it will be insufficient in
> the future.  The postal codes seem to have different structures
> between countries.
> 
> Sounds good. :)
> 
> 
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