Remove holes from multipolygons in geojson file

remove-polygon-holes.js

// DEPS: npm install jsts@0.17.0
// USAGE: node remove_holes.js holey_coverage.geojson solid_coverage.geojson

var fs = require('fs');
var jsts = require("jsts");
var parser = new jsts.io.GeoJSONParser();

var geojson = JSON.parse(fs.readFileSync(process.argv[2], 'utf8'));

var removedHoles = 0;
var holeyPolygons = 0;

for (var l = 0, totalFeatures = geojson.features.length; l < totalFeatures; l++) {
	if (geojson.features[l].geometry.type == 'MultiPolygon') {
		var geoms = parser.read(geojson.features[l].geometry);
		var holes = [];
		for (var i = 0, totalPolygons = geoms.geometries.length; i < totalPolygons; i++) {
			if (geoms.geometries[i].holes.length) {
				for (var j = 0, totalHoles = geoms.geometries[i].holes.length; j < totalHoles; j++) {
					var hole = [];
					for (var k = 0, totalPoints = geoms.geometries[i].holes[j].points.length; k < totalPoints; k++) {
						var point = geoms.geometries[i].holes[j].points[k];
						hole.push([point.x, point.y]);
					}
					holes.push(hole);
					removedHoles++;
				}
				holeyPolygons++;
			}
		}
		geojson.features[l].geometry.coordinates.push(holes);
	}
}

console.log('Removed holes: ' + removedHoles + ' total in ' + holeyPolygons + ' holey polygons');
fs.writeFile(process.argv[3], JSON.stringify(geojson));