Map Chart

This project represents a formalized workflow for the creation of global and US state topojson maps suitable for choropleth charts. The processing pipeline relies on NaturalEarth 10m cultural vector data.

Mapping pipeline

The mapping pipeline is started by calling 'make' from the base directory. The pipeline requires ogr2ogr, node.js, topojson and coffeescript.

brew install node gdal
npm install -g coffee-script
npm install -g topojson
npm install

The default configuration file can be brought in with

cp sample_configurations/config.world_and_states.mk config.mk

Testbed

The testbed needs bower to install its dependencies. From the testbed directory

npm install
npm install -g bower
bower install

Products

With the 'world_and_states' configuration file, the mapping pipeline will produce a single topojson map, worldMap.topo.json, containing three layers:

• countries [national boundaries] with these properties:
  • SOV_A3 (3 letter abbreviation) -> also the id
  • longName (a caveat - this property is renamed from "SOVEREIGNT", so to use it as the id, you'll need to use that original name in the config file.)
• states [US states] with these properties:
  • SOV_A3 ["US1"]
  • longName (
  • postal -> also the id

The file is also automatically copied to the testbed.

Using longName ids

When starting out with choropleth chart making, it might be helpful to use maps where the id of a country is its full name rather than it's 3-letter SOV_A3 tag. To make a map like this, use the alternate config.mk file:

cp sample_configurations/config.world_and_states_by_full_name.mk config.mk

Make options

SIMPLIFY_PROPORTION (0.05) - Will pass this simplification factor to topojson when creating maps.

REMOVE_LAYER ("") - Will remove the named layer from the finished data product. Currently the only valid options are "countries" and "states".

COUNTRY_ID_PROP [SOV_A3] - Sets the property used as an id for the country layer.

STATE_ID_PROP [postal] - Sets the property used as an id for the state layer.

MERGED_STATES_ID_PROP[SOV_A3] - Set to the property in states.json the matches the property name of your COUNTRY_ID_PROP