Function interpolate

test/libs/workers/TurfWorkerForTest.js:19–98

(points, cellSize, options)

//IDW 插值
function interpolate(points, cellSize, options) {
    options = options || {};
    if (typeof options !== 'object') {
        throw new Error('options is invalid');
    }
    var gridType = options.gridType;
    var property = options.property;
    var weight = options.weight;

    if (!points) {
        throw new Error('points is required');
    }
    turf.collectionOf(points, 'Point', 'input must contain Points');
    if (!cellSize) {
        throw new Error('cellSize is required');
    }
    if (weight !== undefined && typeof weight !== 'number') {
        throw new Error('weight must be a number');
    }
    property = property || 'elevation';
    gridType = gridType || 'square';
    weight = weight || 1;

    var box = options.bbox || turf.bbox(points);

    var grid;
    switch (gridType) {
        case 'point':
        case 'points':
            grid = squareGrid(box, cellSize, options, gridType);
            break;
        case 'square':
        case 'squares':
            grid = squareGrid(box, cellSize, options, gridType);
            break;
        case 'hex':
        case 'hexes':
            grid = turf.hexGrid(box, cellSize, options);
            break;
        case 'triangle':
        case 'triangles':
            grid = turf.triangleGrid(box, cellSize, options);
            break;
        default:
            throw new Error('invalid gridType');
    }
    var results = [];
    var gridFeatures = grid.features;
    var pointFeatures = points.features;
    for (var i = 0, len = gridFeatures.length; i < len; i++) {
        var zw = 0;
        var sw = 0;
        var gridFeature = gridFeatures[i];
        for (var j = 0, leng = pointFeatures.length; j < leng; j++) {
            var point = pointFeatures[j];
            var gridPoint = (gridType === 'point') ? gridFeature : turf.centroid(gridFeature);
            var d = turf.distance(gridPoint, point, options);
            var zValue;