Setup (on Mac OS X):

Install Node (http://nodejs.org/). Use HomeBrew (http://brew.sh/) to install node.

Open Terminal on Mac OS X and Run the following

$brew install node

Install http-server

$npm install http-server -g

Incase you do not have npm you can use

curl https://npmjs.org/install.sh | sh

Once installed you can test as given below :

$mkdir MyProject

$cd MyProject

$touch index.html

$echo "Hello World" > index.html

$http-server -p 5000 &

$curl -v "http://localhost:5000/index.html"

Note : You can also test by accessing the URL from a browser window.

Getting Geo Data for India

Download the Geo Data for India (shapefiles).

Note that this would contain the undisputed part of Indian territory only. Google for IND_ADM.zip file (http://archive.lib.msu.edu/maps/public/GISData/ OR http://www.naturalearthdata.com/downloads/10m-cultural-vectors/)

*Unzip the folder IND_ADM and this is what you should see :

├── IND_adm0.csv
├── IND_adm0.dbf
├── IND_adm0.prj
├── IND_adm0.shp
├── IND_adm0.shx
├── IND_adm1.csv
├── IND_adm1.dbf
├── IND_adm1.prj
├── IND_adm1.shp
├── IND_adm1.shx
├── IND_adm2.csv
├── IND_adm2.dbf
├── IND_adm2.prj
├── IND_adm2.shp
├── IND_adm2.shx
├── IND_adm3.csv
├── IND_adm3.dbf
├── IND_adm3.prj
├── IND_adm3.shp
├── IND_adm3.shx
└── read_me.pdf

Download the Disputed territories shape file as well

(source : http://www.naturalearthdata.com/downloads/10m-cultural-vectors/) *Unzip the folder IND_ADM and this is what you should see

├── ne_10m_admin_0_disputed_areas_scale_rank_minor_islands.README.html
├── ne_10m_admin_0_disputed_areas_scale_rank_minor_islands.VERSION.txt
├── ne_10m_admin_0_disputed_areas_scale_rank_minor_islands.cpg
├── ne_10m_admin_0_disputed_areas_scale_rank_minor_islands.dbf
├── ne_10m_admin_0_disputed_areas_scale_rank_minor_islands.prj
├── ne_10m_admin_0_disputed_areas_scale_rank_minor_islands.shp
├── ne_10m_admin_0_disputed_areas_scale_rank_minor_islands.shx

Now we would work with the .shp files only (SHAPE files) to convert into JSON

For this we need the following tools installed :

• gdal (Geospatial Data Abstraction Library - http://www.gdal.org ) which would also install tool ogr2ogr (http://www.gdal.org/ogr2ogr.html)

  $brew install gdal  

• Install Topojson

  $npm install -g topojson

You might need to use sudo if you do get permission denied errors. Now we convert the SHAPE data for INDIA to JSON. Go to the IND_ADM folder and run the following command line :

For extracting data for India (international boundary)

ogr2ogr -f GeoJSON -where "ADM0_A3 IN ('IND')" IND0.json IND_adm0.shp

For extracting data for India with state boundaries

ogr2ogr -f GeoJSON -where "ADM0_A3 IN ('IND')" IND1.json IND_adm1.shp

For extracting data for India with district boundaries

ogr2ogr -f GeoJSON -where "ADM0_A3 IN ('IND')" IND2.json IND_adm2.shp

For extracting data for India with further defined boundaries

ogr2ogr -f GeoJSON -where "ADM0_A3 IN ('IND')" IND3.json IND_adm3.shp

Note : All the JSON above would have data only for the undisputed territories of India

Now we convert the SHAPE data for DISPUTED territories and extract data for India/China/Pakistan to JSON.

• Go to the ne_10m_admin_0_disputed_areas_scale_rank_minor_islands folder and run the following command line :

  ogr2ogr \
  -f GeoJSON \
  -where "sr_adm0_a3 IN ('IND','PAK','CHN')" \
  disputed.json \
  ne_10m_admin_0_disputed_areas_scale_rank_minor_islands.shp

• Now theres a bit of manual merging that is needed .

  Open the disputed.json file. 
  Copy all the {"type" *} , i.e. the content between '"features": [...]'
  Paste the same into '"features":[]' of IND0.json,IND1.json,IND2.json and IND3.json 

  (Will figure out a better way to do this)

Now we are ready to use the json files with D3.

I will provide a TopoJson implementation details of the same later, since geoJSON files are huge. There is a topojson version in the source (india.html)

*I am greatly thankful to Mike Bostock's reference implementation -Lets make a map - "http://bost.ocks.org/mike/map/"