http://civicaccess.416.s1.nabble.com/Zip-codes-and-Electoral-districts-tp865p879.html
> I don't see how this can be copyrighted. Someone (you Daniel ?) told
> that facts can't be copyrighted. I just can't imagine how this could
it is a unique arrangement of facts. Most databases are full of facts,
rivers, households, telephone numbers. It is not the fact but the
>
> Concerning the other points you raise :
> - It's amazing that postal codes can overlap several districts... but
> I can't see how to solve this. Even the Election Canada website uses
> the postal code to find your district.
> - I don't see how you get only 1 millions possibilites with this
> regex. You bring the first character from 26 letters to 19. The result
> is 19*10*26*10*26*10 = 12 millions
>
>
> Franck :
>
> I understand you point. However I still don't understand why those
> data are not freely accessible. If they are not available I'll pick
> them... if I can ;)
>
> Steph
>
> Daniel Haran wrote:
>> Hi Stéphane,
>>
>> There are a few problems with that approach. First of all, the
>> lat/long mapping databases tend to be copyrighted themselves. Besides,
>> those are the centroids - the center-most point of a polygon.
>>
>> One of the main problems Russell mentioned (and explained further at
>>
http://www.digital-copyright.ca/node/1607 ) is that the mapping is not
>> one to one. A postal code region can overlap several electoral
>> districts.
>>
>> The drupal lobby module he mentioned has a good regular expression for
>> validating postal codes:
>> /([ABCEGHJKLMNPRSTVXY]\d[A-Z]\s?\d[A-Z]\d)/i
>>
>> For non-techies, that first segment ABC...Y are all the allowable
>> first letters in a postal code. That reduces the number of
>> possibilities to 1,216,800 from 17,576,000. At a second a piece,
>> that's a bit over 14 days from 100 :)
>>
>> cheers,
>>
>> Daniel.
>>
>> On 2/8/07, Stéphane Zagar <
[hidden email]> wrote:
>>
>>> Hey
>>>
>>> In fact, technically it's not complicated to get a zip code mapping with
>>> latitude and longitude :
>>>
>>> H3T1A1;45.5113;-73.6162
>>> H3T1B1;45.5083;-73.6183
>>> H3T1C1;45.5016;-73.6245
>>> H3T1E1;45.4974;-73.628
>>> H3T1G1;45.51;-73.614
>>> H3T1H1;45.5061;-73.6176
>>> H3T1J1;45.4945;-73.6282
>>> H3T1K1;45.5002;-73.6212
>>> H3T1L1;45.4962;-73.6253
>>> H3T1M1;45.4971;-73.6225
>>> H3T1N1;45.501;-73.6178
>>> H3T1P1;45.4942;-73.6229
>>> H3T1R1;45.5105;- 73.6154
>>> H3T1S1;45.5078;-73.6178
>>> H3T1T1;45.5052;-73.6198
>>> H3T1V1;45.5005;-73.6192
>>> H3T1W1;45.4987;-73.6208
>>> H3T1X1;45.4971;-73.6212
>>> H3T1Y1;45.4959;-73.6206
>>> H3T1Z1;45.4977;-73.6257
>>>
>>> And I think it's not that much complicated to do the same reverse
>>> engineering for electoral district.
>>>
>>> The problem is that mathematically, there are about 17 millions of valid
>>> combination of zip code. It take about 1 sec for my script to retrieve the
>>> zipcode/lat-long so if we do a basic computation it gives us about... 100
>>> days to retrieve everything (and probably a lot of bandwidth). Even if we
>>> set the last number to 1 (what I did in my previous test), it's still about
>>> 2 millions valid values. And I'm not sure if the website I use to retrieve
>>> this will allow this (with 1 request/sec, I can't imagine they won't see
>>> that something is happening).
>>>
>>> By the way, I have a question for geostuff people (Tracey ?) : On the
>>> geogratis website, there are some files concerning the electoral districts (
>>>
http://geogratis.cgdi.gc.ca/geogratis/en/option/select.do?id=1169),
>>> but I don't know anything concerning the format (Arc Export or shape file).
>>> Is there a way to do something with that ? For example do a process
>>> what-ever to find out in which electoral district is a point (long-lat) ?
>>>
>>> Steph
>>>
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>>>
>>
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