@trailstash/ultra/lib/sparql2geojson.js

A web based tool for making MapLibre GL maps with data from sources such as Overpass, GeoJSON, GPX, KML, TCX, etc

import wkt from "wkt";

const wktDataTypes = new Set([
  "http://www.opengis.net/ont/geosparql#wktLiteral",
  "http://www.openlinksw.com/schemas/virtrdf#Geometry",
]);

export default function (sparqlJSON) {
  return {
    type: "FeatureCollection",
    features: sparqlJSON.results.bindings.map((record) => {
      const properties = {};
      let geometry;
      for (const [key, { datatype, value }] of Object.entries(record)) {
        if (wktDataTypes.has(datatype)) {
          geometry = wkt.parse(value);
        } else {
          properties[key] = value;
        }
      }
      return {
        type: "Feature",
        geometry,
        properties,
      };
    }),
  };
}