The new version of es-atlas will incorporate the option to preproject the TopoJSON's. With this option a new object is included within the TopoJSON that lets you to draw a composition border for the Canary Islands as usual in this kind of maps.
xxxxxxxxxx<script src="https://unpkg.com/d3-composite-projections"></script><script src="https://d3js.org/d3.v5.min.js"></script><script src="https://d3js.org/topojson.v3.min.js"></script><svg></svg><script> const margin = { top: 20, right: 20, bottom: 20, left: 20 }, width = window.innerWidth - margin.left - margin.right, height = width * 0.8 - margin.top - margin.bottom; const svg = d3 .select("svg") .attr("width", width) .attr("height", height); d3.json("municipalities.json") .then(es => { const projection = d3 .geoIdentity() .reflectY(false) .fitSize( [width - margin.left - margin.right, height], topojson.feature(es, es.objects.border) ); const path = d3.geoPath(projection); svg .datum(topojson.feature(es, es.objects.municipalities)) .append("path") .attr("fill", "none") .attr("stroke", "black") .attr("d", path); svg .append("path") .datum(topojson.feature(es, es.objects.composite_border)) .attr("d", d => path(d)) .attr("fill", "none") .attr("stroke", "black"); }) .catch(err => console.warn(err));</script> https://unpkg.com/d3-composite-projections
https://d3js.org/d3.v5.min.js
https://d3js.org/topojson.v3.min.js