Tools needed to install (if no installed)

brew install wget
brew install ogr2ogr
npm install -g topojson

Extract Data

1. Fetch zip file containing shapefile;

source fetch.sh

2. Find the file ending with .shp

3. Extract data from .shp with ogr2ogr We need to extract Hongkong and Taiwan from ne_10m_admin_0_countries.shp, and China Mainland and Macao from ne_10m_admin_1_states_provinces.shp, and then merge the two layers.

Extract Hongkong, Macao and Taiwan:

ogr2ogr -f GeoJSON -where "ADM0_A3 IN ('HKG')" .tmp/hongkong.json .tmp/ne_10m_admin_0_countries/ne_10m_admin_0_countries.shp

Extract Macao:

ogr2ogr -f GeoJSON -where "ADM0_A3 IN ('MAC')" .tmp/macao.json .tmp/ne_10m_admin_0_countries/ne_10m_admin_0_countries.shp

Extract Taiwan:

ogr2ogr -f GeoJSON -where "ADM0_A3 IN ('TWN')" .tmp/taiwan.json .tmp/ne_10m_admin_0_countries/ne_10m_admin_0_countries.shp

Extract provinces of China Mainland:

ogr2ogr -f GeoJSON -where "adm0_a3 IN ('CHN')" .tmp/mainland.json .tmp/ne_10m_admin_1_states_provinces/ne_10m_admin_1_states_provinces.shp

4. Use topojson to combine the two layers, simply the outline, and delete unnecessary json fileds. Keep some attributes like name_local, adm0_a3.

topojson -o china.json -p name,name_local,adm0_a3,longitude,latitude,NAME,ADM0_A3,LONGITUDE,LATITUDE -- mainland.json hongkong.json macao.json taiwan.json

5. To preview and simplify the your data, go to http://www.mapshaper.org/