es-atlas

Pre-built TopoJSON from the Spanish National Geographic Institute

Usage no npm install needed!

<script type="module">
  import esAtlas from 'https://cdn.skypack.dev/es-atlas';
</script>

README

Spain Atlas TopoJSON

This repository provides a simple script to generate TopoJSON files from the Spanish National Geographic Institute’s National Reference Geographic Equipment vector data.

Usage

In a browser (using d3-geo and SVG):

<!DOCTYPE html>
<svg width="960" height="500"></svg>
<script src="https://d3js.org/d3.v6.min.js"></script>
<script src="https://d3js.org/topojson.v3.min.js"></script>
<script src="https://unpkg.com/d3-composite-projections@1.4.0"></script>
<script>

const svg = d3.select("svg");
const projection = d3.geoConicConformalSpain();
const path = d3.geoPath(projection);

d3.json("https://unpkg.com/es-atlas/es/municipalities.json")
  .catch(err => console.warn(err));
  .then(es => {
    svg
      .append('path')
      .attr('d', path(topojson.mesh(es)))
      .attr('fill', 'none')
      .attr('stroke', 'black');

    svg
      .append('path')
      .attr('d', projection.getCompositionBorders())
      .attr('fill', 'none')
      .attr('stroke', 'black');
  })
</script>

In Node (using d3-geo and node-canvas):

const fs = require('fs');
const d3_composite = require('d3-composite-projections');
const d3 = require('d3-geo');
const topojson = require('topojson-client');
const Canvas = require('canvas');
const es = require('./node_modules/es-atlas/es/municipalities.json');

const canvas = new Canvas(960, 500);
const context = canvas.getContext('2d');
const projection = d3_composite.geoConicConformalSpain();
const path = d3.geoPath(projection, context);

context.beginPath();
path(topojson.mesh(es));
context.stroke();

canvas.pngStream().pipe(fs.createWriteStream('preview.png'));

I highly recommend using Roger Veciana’s d3-composite-projections with these files. Using a geoConicConformalSpain projection will ensure that the Canary Islands are painted closer to the mainland and even add a border to mark the projection zone.

Generating the files

Clone or download the repo, start a terminal and run npm install in the folder. This command will run the script and move the generated files to the es folder.

If you need to make further adjustments (simplification, quantization) you can change the package.json config and run npm install again.

Reference

# simplification

Removes points to reduce the file size. Set to 1e-4 by default.

# quantization

Removes information by reducing the precision of each coordinate. Set to 1e4 by default.

# autonomous_regions

Filters the result by the given autonomous region id separated by comma.

File Reference

# es/municipalities.json <>

A TopoJSON which contains four objects: municipalities, provinces, autonomous regions and border. Every city, province and region has its corresponding National Statistics Institute identifier and name, so it's easy to get started.

# es.objects.municipalities

# es.objects.provinces

# es.objects.autonomous_regions

# es.objects.border

# es/provinces.json <>

This file provides provinces and autonomous regions, to keep a smaller footprint on less detailed maps.

# es/autonomous_regions.json <>

This file only provides autonomous regions, to keep a smaller footprint on less detailed maps.

Data license

The shapefiles have a CC-BY 4.0 license. You need to accept the terms before using the files.

Inspiration

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