ccalobeto / latam-atlas

Pre-built TopoJSON files to load your map faster

Latin America Atlas TopoJSON

This repository provides topoJSON files you can use as a cartography on a webpage or using Plot in observablehq, see an example here

To align the names of subnational jurisdictions in different countries, four levels have been set:

• level1: country
• level2: provinces / departments
• level3: cantons / provinces
• level4: parishes / districts

Generating the files

Clone or download the repo and start a terminal. Then run npm run prepublishOnly to transform the downloaded zip files into topojson files.

If you need to make further adjustments (projection, simplification, quantization) you can change the prepublish config file and run npm run prepublishOnly again.

Concepts

# simplification

Removes points to reduce the file size. Set to 3% by default.

# quantization

Removes information by reducing the precision of each coordinate. Set to 1e5 by default.

File Reference

The TopoJSON files contain 4 levels of geometry based on and id code, which in Ecuador is DPA_PARROQ and in Perú is UBIGEO . The geometry is quantized and simplified.

Each level4 has two properties:

• level4.id - the six-digit code, such as "010152"
• level4.properties.name - the district name, such as "CUMBE"

For the level 2 the first two digits of the id code is the province code. For the level 3 the first four digits of the id code is the canton code.

TopoJSON files

Ecuador

• Source: Ecuador cartographic boundary shapefiles
• Projection: https://epsg.io/32717.
• Download

To visualize with d3.js:

d3
    .geoIdentity()
    .reflectY(true)
    .fitSize([width, height], features)

Parishes

Perú

• Source: Perú cartographic boundary shapefiles
• Projection: https://epsg.io/4326.
• Download

To visualize with d3.js:

d3
    .geoIdentity()
    .reflectY(true)
    .fitSize([width, height], features)

Districts

Inspiration

The original idea and implementation comes from Mike Bostock’s us-atlas and trase-atlas.