U.S. Atlas, Redux [UNLISTED]

.block

license: bsd-3-clause

README.md

A demonstration of the new command-line tools in TopoJSON 2.0, d3-geo-projection 1.1 and ndjson-cli.

us-albers-10m.sh

#!/bin/bash

# Make a working directory.
mkdir -p counties

# Download the U.S. county boundaries, one-million scale.
# https://nationalmap.gov/small_scale/atlasftp.html
curl -o counties/counties.tar.gz 'https://prd-tnm.s3.amazonaws.com/StagedProducts/Small-scale/data/Boundaries/countyp010g.shp_nt00934.tar.gz'

# Expand the downloaded tarball into the working directory.
tar -vxzm -C counties -f counties/counties.tar.gz

# Convert to TopoJSON!
# shp2json converts the counties shapefile to GeoJSON.
# ndjson-filter removes “water” counties (e.g., Great Lakes).
# ndjson-map assigns an id and removes extraneous properties.
# geostitch removes antimeridian cuts, if any.
# geoproject applies D3’s U.S. Albers composite equal-area projection.
# geo2topo converts the GeoJSON to quantized TopoJSON.
# toposimplify simplifies the TopoJSON while preserving topology.
# topomerge merges counties into states, and then states into the nation.
geo2topo -n -q 1e5 counties=<( \
    shp2json -n counties/countyp010g.shp \
      | ndjson-filter '!/000$/.test(d.properties.ADMIN_FIPS)' \
      | ndjson-map '(d.id = d.properties.ADMIN_FIPS, delete d.properties, d)' \
      | geostitch -n \
      | geoproject -n 'd3.geoAlbersUsa()') \
  | toposimplify -f -p 0.25 \
  | topomerge states=counties -k 'd.id.slice(0, 2)' \
  | topomerge nation=states \
  > us-albers-10m.json

# Convert to SVG!
cat us-albers-10m.json \
  | topo2geo -n counties=- \
  | geo2svg -n -p 2 \
  > us-albers-10m.svg

Sweet!