MISC

kinks

npm install @turf/kinks

接收一个 type 为 LineString、MultiLineString、Polygon、MultiPolygon 的要素，计算并返回所有自相交的点要素

参数

返回

FeatureCollection<Point>

范例

var poly = turf.polygon([
  [
    [-12.034835, 8.901183],
    [-12.060413, 8.899826],
    [-12.03638, 8.873199],
    [-12.059383, 8.871418],
    [-12.034835, 8.901183]
  ]
]);
var kinks = turf.kinks(poly); // 返回要素集

lineArc

npm install @turf/line-arc

接收一个中心和半径，两个角度，计算出由 bearing1 为起点、bearing2 为终点的指定的圆弧并返回。

值得注意的是，角度是与正北方向所形成的角度，顺时针为正值，且两个角度有先后顺序

参数

options

返回

Feature<LineString>

范例

var center = turf.point([-75, 40]);
var radius = 5;
var bearing1 = 25;
var bearing2 = 47;
var arc = turf.lineArc(center, radius, bearing1, bearing2);
/*
{
  type: "Feature",
  geometry: {
    type: "LineString",
    coordinates: [
      [-74.97517792609881, 40.04075040571227],
      [-74.97008079359495, 40.038690305118934],
      [-74.96527228827969, 40.03625742190849],
      [-74.96079876149496, 40.03347522459089],
      [-74.95705100267124, 40.03065882615696]
    ]
  },
  properties: {}
}
*/

lineChunk

npm install @turf/link-chunk

接收一个 type 为 LineString 的线要素，切分成指定长度的线段并返回要素集

值得注意的是，如果入参的线段小于要切分的长度，则返回入参的线段

参数

options

返回

FeatureCollection<LineString>

范例

var line = turf.lineString([
  [-95, 40],
  [-93, 45],
  [-85, 50]
]);
var chunk = turf.lineChunk(line, 15, { units: "miles" }); // 间隔15英里切分一段线段

lineIntersect

npm install @turf/line-intersect

接收两个任意的 type 为 LineString 或 Polygon 的 GeoJSON，并返回所有的相交点

参数

返回

FeatureCollection<Point>

范例

var line1 = turf.lineString([
  [126, -11],
  [129, -21]
]);
var line2 = turf.lineString([
  [123, -18],
  [131, -14]
]);
var intersects = turf.lineIntersect(line1, line2);
/*
{
  type: "FeatureCollection",
  features: [
    {
      type: "Feature",
      geometry: {
        type: "Point",
        coordinates: [127.43478260869566, -15.782608695652174]
      },
      properties: {}
    }
  ]
}
*/

lineOverlap

npm install @turf/line-overlap

接收两个任意的 type 为 LineString 或 Polygon 的 GeoJSON，并返回它们的重叠线

值得注意的是，重叠线可能有多条

参数

options

返回

FeatureCollection<LineString>

范例

var line1 = turf.lineString([
  [115, -35],
  [125, -30],
  [135, -30],
  [145, -35]
]);
var line2 = turf.lineString([
  [115, -25],
  [125, -30],
  [135, -30],
  [145, -25]
]);
var overlapping = turf.lineOverlap(line1, line2); // [125, -30], [135, -30] 线段重叠

lineSegment

npm install @turf/line-segment

接收一个线要素(LineString)或面要素(Polygon)，创建 2-vertex 的线段要素集合

参数

返回

FeatureCollection<LineString>

范例

var polygon = turf.polygon([
  [
    [-50, 5],
    [-40, -10],
    [-50, -10],
    [-40, 5],
    [-50, 5]
  ]
]);
var segments = turf.lineSegment(polygon);

lineSlice

npm install @turf/line-slice

接收一条线要素(LineString)、起点、终点，裁切起终点之间的在该线的线段并返回

值得注意的是，起点终点不需要在线上，会计算出点到线最近的点

参数

返回

Feature<LineString>

范例

var line = turf.lineString([
  [-77.031669, 38.878605],
  [-77.029609, 38.881946],
  [-77.020339, 38.884084],
  [-77.025661, 38.885821],
  [-77.021884, 38.889563],
  [-77.019824, 38.892368]
]);
var start = turf.point([-77.029609, 38.881946]);
var stop = turf.point([-77.021884, 38.889563]);
var sliced = turf.lineSlice(start, stop, line); // 返回裁切的线段GeoJSON

lineSliceAlong

npm install @turf/line-slice-along

接收一条线要素(LineString)、起点距离、终点距离，计算出沿起点在线上的指定距离、沿终点在线上的指定距离，裁切这两点之间的该线的线段并返回

值得注意的是，起点距离的点超过终点距离的点也没关系，只是坐标顺序相反而已

参数

options

返回

Feature<LineString>

范例

var line = turf.lineString([
  [7, 45],
  [9, 45],
  [14, 40],
  [14, 41]
]);
var start = 12.5;
var stop = 25;
var sliced = turf.lineSliceAlong(line, start, stop, { units: "miles" });
/*
{
  type: "Feature",
  geometry: {
    type: "LineString",
    coordinates: [
      [7.25584134370955, 45.00194719009643],
      [7.511697527558178, 45.003323144337116]
    ]
  }
}
*/

lineSplit

npm install @turf/line-split

接收一个线要素(LineString)，一个用于裁切的任意要素(Feature)，计算并返回裁切后的线要素集

参数

返回

FeatureCollection<LineString>

范例

var line = turf.lineString([
  [120, -25],
  [145, -25]
]);
var splitter = turf.lineString([
  [130, -15],
  [130, -35]
]);
var split = turf.lineSplit(line, splitter); // 两个线要素的要素集

mask

npm install @turf/mask

接收一个 type 为 polygon 或 MultiPolygon 的面要素，作为内圈。返回一个挖孔的面要素作为遮罩

参数

返回

Feature<Polygon>

范例

var polygon = turf.polygon([
  [
    [112, -21],
    [116, -36],
    [146, -39],
    [153, -24],
    [133, -10],
    [112, -21]
  ]
]);
var mask = turf.polygon([
  [
    [90, -55],
    [170, -55],
    [170, 10],
    [90, 10],
    [90, -55]
  ]
]);
var masked = turf.mask(polygon, mask);

nearestPointOnLine

npm install @turf/nearest-point-on-line

接收一个点要素和一个线要素，计算出该点在该线上最近的点要素并返回

值得注意的是，返回的点要素的 properties 包括三个值：index：在第 n 个直线上找到的点；dist：pt 和该点要素之间的距离；location：沿着起点到该点要素的线的距离

参数

options

返回

Feature<Point>

范例

var line = turf.lineString([
  [-77.031669, 38.878605],
  [-77.029609, 38.881946],
  [-77.020339, 38.884084],
  [-77.025661, 38.885821],
  [-77.021884, 38.889563],
  [-77.019824, 38.892368]
]);
var pt = turf.point([-77.037076, 38.884017]);
var snapped = turf.nearestPointOnLine(line, pt, { units: "miles" }); // [-77.02996941477018, 38.881361463229524]的点要素

sector

npm install @turf/sector

接收一系列参数(具体看下述列表)，计算出 type 为 polygon 的扇形区域并返回

值得注意的是，角度是与正北方向所形成的角度，顺时针为正值，且两个角度有先后顺序

参数

options

返回

Feature<Polygon>

范例

var center = turf.point([-75, 40]);
var radius = 5;
var bearing1 = 25;
var bearing2 = 45;
var sector = turf.sector(center, radius, bearing1, bearing2); // type 为 Polygon 的扇形面要素

shortestPath

npm install @turf/shortest-path

接收两个点，返回这两个点的最短距离路径，且不与传入的障碍物碰撞

参数

options

返回

FeatureCollection<LineString>

范例

var start = [-5, -6];
var end = [9, -6];
var options = {
  obstacles: turf.polygon([
    [
      [0, -7],
      [5, -7],
      [5, -3],
      [0, -3],
      [0, -7]
    ]
  ])
};
var path = turf.shortestPath(start, end, options);

unkinkPolygon

npm install @turf/unkink-polygon

接收一个有自相交的面要素(Polygon)，计算并返回没有自相交的面要素集合，如果入参没有自相交，则返回入参数据的要素集

参数

返回

FeatureCollection<Polygon>

范例

var poly = turf.polygon([
  [
    [0, 0],
    [2, 0],
    [0, 2],
    [2, 2],
    [0, 0]
  ]
]);
var result = turf.unkinkPolygon(poly);