[datameet] GeoBLR April 6, 6pm at Mapbox

[Sajjad Anwar]

Hey everyone,

I want to invite you to our March - April edition of GeoBLR, this
Wednesday 6pm at Mapbox. Vaibhav Bhawsar (http://www.recombine.net/)
will talk about his experiences building timescape.io and lead a
discussion on interactive map making.

RSVP is currently full, but do feel free to drop by!
http://www.meetup.com/GeoBLR/events/229810473/

Looking forward.

Cheers,
Sajjad

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Re: [datameet] Pincode Boundaries of India

[Avinash Celestine]

Adding some relevant data.

The district handbooks released by census provide pincode details for
village areas. for each village / location code, they provide the relevant
pincode which covers that village. I have collated that data from the
handbook files and put them up here:

https://github.com/avinashcelestine/pincodes_censuscodes

Unfortunately, the district handbooks only provide such pincode data for
villages, not towns or wards. And even within villages, a number of
locations dont have the relevant pincode info (i think a large part of
Madhya Pradesh is blank for instance). Another bunch of villages have
pincodes in less than 6 digits. Despite these issues however, there are
still 4.13 lakh villages out of a total of 6.4 lakh, for whom six digit
pincodes are given.

the handbooks are here:
http://www.censusindia.gov.in/2011census/dchb/DCHB.html

(For the sake of completeness, i have not removed entries for those
villages for which pincodes are not given)

These will be useful for anyone looking to map census data to pincodes.

regards

Avinash

On Sun, Apr 3, 2016 at 6:47 PM, Dilip Damle  wrote:

> Hi Devdatta,
>
> What is the data that you are looking for.
> I had saved it.
> But it is huge. About 1.55 GB consisting of about 135 shapefiles out of
> which 70 are raw booths.
>
>
>
> On Saturday, April 2, 2016 at 12:32:47 PM UTC+5:30, Devdatta Tengshe wrote:
>>
>> Hi Raphael,
>>
>> Firstly, thanks a lot for extracting this information.
>>
>> I was looking at http://dx.doi.org/10.4119/unibi/2674065, but I could
>> find only the Boundaries for the constituencies.
>>
>> Can you tell us where we can find the locations of the polling booths
>> that you had extracted?
>>
>> Secondly, can you also share (if you still have them) the heatmaps code
>> that you used to create the constituency boundaries? I think that is what
>> will be required to create the pincode boundaries as well.
>>
>> Regards,
>> Dev
>>
>> Regards,
>> Devdatta
>>
>> On Fri, Apr 1, 2016 at 6:31 PM, Raphael Susewind <
>> li...@raphael-susewind.de> wrote:
>>
>>> Dear all,
>>>
>>> following up on my earlier email, I just pushed a list of pincodes for
>>> all electoral booths across India to GitHub and made a pull request to
>>> the datameet repository:
>>>
>>> https://github.com/datameet/pincodes/pull/2
>>>
>>> Please note that this can be incomplete, and is based on a rather
>>> brutish, quick and dirty hack - see comments in rolls2pincode.pl. But it
>>> does use the same IDs as those in the 2014 elections, and hence can be
>>> combined with my GIS shapefiles for polling booths:
>>>
>>> http://dx.doi.org/10.4119/unibi/2674065
>>>
>>> I leave it to others to double-check accuracy and create actual pincode
>>> maps. I hope this is useful,
>>>
>>> Best,
>>> Raphael
>>>
>>> On 28.03.2016 07:50, Raphael Susewind wrote:
>>>
>>> > Dear Avinash and all,
>>> >
>>> > I will try to make some time this week to scrape the pincodes from
>>> > electoral rolls for all polling booths in my electoral GIS shapefiles.
>>> >
>>> > Since pincode is in latin script, this should not be affected by the
>>> > much discussed PDF scraping issues with electoral rolls.
>>> >
>>> > We could then either go down the voronoi route, or alternatively use
>>> the
>>> > heatmap processing chain that I used to generate AC boundaries - this
>>> > latter would have the advantage of dealing with wrong coordinates in
>>> the
>>> > booth point dataset (basically, not all electoral booth coordinates are
>>> > correct; consequently, if we only voronoi, we would have a blip of
>>> > pincode B within a see of pincode A quite frequently. The heatmap stuff
>>> > takes care of this).
>>> >
>>> > Since I am not familiar with postal boundaries: can anyone here confirm
>>> > whether pincode areas are contiguous, and whether each pincode has only
>>> > one area? Or can it be that several non-contiguous areas have the same
>>> > pincodem intersparsed with other pincodes? (In which case voronoi would
>>> > perhaps be the better solution at last)
>>> >
>>> > In any case, I hope to give you the pincode for each polling booth by
>>> > end of the week or so (based on all-India 2014 electoral rolls),
>>> >
>>> > Best,
>>> > Raphael
>>> >
>>> > On 28.03.2016 06:33, Avinash Celestine wrote:
>>> >
>>> >> perhaps one way is to avoid using postal data altogether.
>>> >>
>>> >> All header pages in electoral rolls(the first page) contain the name
>>> of
>>> >> the polling station related to that roll, the PS number, and
>>> importantly
>>> >> the pin code.
>>> >>
>>> >>  A site like psleci.nic.in  has geog
>>> coordinates
>>> >> of polling stations (though Raphael had collected the data earlier*).
>>> >> Matching the two will give a fairly dense scattering of points  - in
>>> >> fact much more dense than if we used some of the methods earlier in
>>> this
>>> >> thread.
>>> >>
>>> >> We thus have a way of associating a pin code with a geo coordinate. We
>>> >> can then use the voronoi m