turf-subdivide-proposal

turf-subdivide-proposal.html

<script src='https://npmcdn.com/@turf/turf/turf.min.js'></script>
<script>
var lineString = {
    "type": "Feature",
    "properties": {},
    "geometry": {
        "type": "LineString",
        "coordinates": [
            [
                13.0078125,
                19.31114335506464
            ],
            [-73.47656249999999,
                5.266007882805498
            ]
        ]
    }
}
var polygon = {
    "type": "Feature",
    "properties": {},
    "geometry": {
        "type": "Polygon",
        "coordinates": [
            [
                [-90.3515625,
                    45.583289756006316
                ],
                [-49.21875,
                    45.583289756006316
                ],
                [-49.21875,
                    57.136239319177434
                ],
                [-90.3515625,
                    57.136239319177434
                ],
                [-90.3515625,
                    45.583289756006316
                ]
            ],
            [
                [-61.17187499999999,
                    49.61070993807422
                ],
                [-72.0703125,
                    39.639537564366684
                ],
                [-62.57812500000001,
                    34.30714385628804
                ],
                [-48.8671875,
                    34.88593094075317
                ],
                [-41.484375,
                    45.82879925192134
                ],
                [-38.3203125,
                    48.922499263758255
                ],
                [-61.17187499999999,
                    49.61070993807422
                ]
            ]
        ]
    }
}

var polygonAfter = subdivide(polygon, 100);
var lineStringAfter = subdivide(lineString, 100);
var fc = turf.featureCollection([polygon, polygonAfter, lineString, lineStringAfter]);

// console.log( 'Polgon - Before', JSON.stringify( polygon ) );
// console.log( 'Polgon - After', JSON.stringify( polygonAfter ) );
// console.log();
// console.log( 'LineString - Before', JSON.stringify( lineString ) );
// console.log( 'LineString - After', JSON.stringify( subdivide(lineStringAfter, 100) ) );

console.log( JSON.stringify( fc ) );


function subdivide(feature, maximumLength, units) {
    feature = JSON.parse(JSON.stringify(feature));
    var arrayOfCoordinates = [];
    if (feature.geometry.type === 'Polygon') {
        arrayOfCoordinates = feature.geometry.coordinates;
    } else if (feature.geometry.type === 'LineString') {
        arrayOfCoordinates = [feature.geometry.coordinates];
    }

    var newCoordinates = [];
    for (var partIndex = 0; partIndex < arrayOfCoordinates.length; partIndex++) {
        var part = arrayOfCoordinates[partIndex];
        var origin = turf.point(part[0]);
        var destination = turf.point(part[part.length - 1]);

        var subCoordinates = [];
        for (var coordinatesIndex = 0; coordinatesIndex < part.length - 1; coordinatesIndex++) {
            var fromCoordinates = part[coordinatesIndex];
            var toCoordinates = part[coordinatesIndex + 1];
            var from = turf.point(fromCoordinates);
            var to = turf.point(toCoordinates);
            var bearing = turf.bearing(from, to);
            var distance = turf.distance(from, to, units);
            var numberOfSubdivision = Math.floor(distance / maximumLength);
            var segmentLength = distance / numberOfSubdivision;

            subCoordinates.push(fromCoordinates);

            for (var s = 1; s < numberOfSubdivision; s++) {
                var currentDistance = s * segmentLength;
                var point = turf.destination(from, currentDistance, bearing, units);
                var newStopCoordinates = point.geometry.coordinates;
                subCoordinates.push(newStopCoordinates);
            }
        }
        subCoordinates.push(part[part.length - 1]);
        newCoordinates[partIndex] = subCoordinates;
    }

    if (feature.geometry.type === 'Polygon') {
        feature.geometry.coordinates = newCoordinates;
    } else if (feature.geometry.type === 'LineString') {
        feature.geometry.coordinates = newCoordinates[0];
    }
    return feature;
}
</script>