meta

coordAll

npm install @turf/meta

接收任意的 GeoJSON 对象(包括要素集)，以二维数组的形式返回它们的坐标

参数

入参 类型 描述
geojson FeatureCollection\ Feature\ Geometry 任意 GeoJSON 对象

返回

Array

范例

  1. var features = turf.featureCollection([
  2.   turf.point([26, 37], { foo: "bar" }),
  3.   turf.point([36, 53], { hello: "world" })
  4. ]);
  6. var coords = turf.coordAll(features);
  7. //= [[26, 37], [36, 53]]
  9. var coords = turf.coordAll(turf.point([26, 37], { foo: "bar" }));
  10. //= [[26, 37]] 虽然只有一个要素，还是以二维数组的形式返回

coordEach

npm install @turf/meta

遍历接收的 GeoJSON 对象，功能类似 Array.forEach()

参数

入参 类型 描述
geojson FeatureCollection\ Feature\ Geometry 任意 GeoJSON 对象
callback Function 回调，参数依次是 currentCoord、coordIndex、featureIndex、multiFeatureIndex
excludeWrapCoord Boolean 是否包含最后一个坐标对(针对闭环线、面要素等坐标是首位闭合的情况)，默认为 false

返回

undefined

范例

  1. var features = turf.featureCollection([
  2.   turf.point([26, 37], { foo: "bar" }),
  3.   turf.point([36, 53], { hello: "world" })
  4. ]);
  6. turf.coordEach(features, function (
  7.   currentCoord,
  8.   coordIndex,
  9.   featureIndex,
  10.   multiFeatureIndex,
  11.   geometryIndex
  12. ) {
  13.   //=currentCoord
  14.   //=coordIndex
  15.   //=featureIndex
  16.   //=multiFeatureIndex
  17.   //=geometryIndex
  18. });

coordReduce

npm install @turf/meta

接收任意 GeoJSON 对象(包括要素集)，遍历累加操作。功能类似 Array.reduce()

参数

入参 类型 描述
geojson FeatureCollection\ Feature\ Geometry 任意 GeoJSON 对象
callback Function 回调，参数依次是 previousValue、currentCoord、coordIndex、featureIndex、multiFeatureIndex、geometryIndex
initial (*) 初始值
excludeWrapCoord Boolean 是否包含最后一个坐标对(针对闭环线、面要素等坐标是首位闭合的情况)，默认为 false

返回

*

范例

  1. var features = turf.featureCollection([
  2.   turf.point([26, 37], { foo: "bar" }),
  3.   turf.point([36, 53], { hello: "world" })
  4. ]);
  6. turf.coordReduce(features, function (
  7.   previousValue,
  8.   currentCoord,
  9.   coordIndex,
  10.   featureIndex,
  11.   multiFeatureIndex,
  12.   geometryIndex
  13. ) {
  14.   //=previousValue
  15.   //=currentCoord
  16.   //=coordIndex
  17.   //=featureIndex
  18.   //=multiFeatureIndex
  19.   //=geometryIndex
  20.   return currentCoord;
  21. });

featureEach

npm install @turf/meta

遍历接收的 GeoJSON 对象，功能类似 Array.forEach()

参数

入参 类型 描述
geojson FeatureCollection\ Feature\ Geometry 任意 GeoJSON 对象
callback Function 回调，参数依次是 currentFeature、featureIndex

返回

undefined

范例

  1. var features = turf.featureCollection([
  2.   turf.point([26, 37], { foo: "bar" }),
  3.   turf.point([36, 53], { hello: "world" })
  4. ]);
  6. turf.featureEach(features, function (currentFeature, featureIndex) {
  7.   //=currentFeature
  8.   //=featureIndex
  9. });

featureReduce

npm install @turf/meta

接收任意 GeoJSON 对象(包括要素集)，遍历累加操作。功能类似 Array.reduce()

参数

入参 类型 描述
geojson FeatureCollection\ Feature\ Geometry 任意 GeoJSON 对象
callback Function 回调，参数依次是 previousValue、currentFeature、featureIndex
initialValue (*) 初始值

返回

*

范例

  1. var features = turf.featureCollection([
  2.   turf.point([26, 37], { foo: "bar" }),
  3.   turf.point([36, 53], { hello: "world" })
  4. ]);
  6. turf.featureReduce(features, function (previousValue, currentFeature, featureIndex) {
  7.   //=previousValue
  8.   //=currentFeature
  9.   //=featureIndex
  10.   return currentFeature;
  11. });

flattenEach

npm install @turf/meta

遍历接收的任意 GeoJSON 对象(包括要素集)。功能类似 Array.forEach()

值得注意的是，如果是多要素集，做扁平处理再遍历，功能类似 Array.flat()

参数

入参 类型 描述
geojson FeatureCollection\ Feature\ Geometry 任意 GeoJSON 对象
callback Function 回调，参数依次是 currentFeature、featureIndex、multiFeatureIndex

范例

  1. var features = turf.featureCollection([
  2.   turf.point([26, 37], { foo: "bar" }),
  3.   turf.multiPoint(
  4.     [
  5.       [40, 30],
  6.       [36, 53]
  7.     ],
  8.     { hello: "world" }
  9.   )
  10. ]);
  12. turf.flattenEach(features, function (currentFeature, featureIndex, multiFeatureIndex) {
  13.   //=currentFeature
  14.   //=featureIndex
  15.   //=multiFeatureIndex
  16.   console.log(currentFeature);
  17. });
  18. /* 输出三个点要素
  19. {
  20.   type: "Feature",
  21.   geometry: {
  22.     coordinates: [26, 37],
  23.     type: "Point"
  24.   },
  25.   properties: { foo: "bar" }
  26. }
  27. {
  28.   type: "Feature",
  29.   geometry: {
  30.     coordinates: [40, 30],
  31.     type: "Point"
  32.   },
  33.   properties: { hello: "world" }
  34. }
  35. {
  36.   type: "Feature",
  37.   geometry: {
  38.     coordinates: [36, 53],
  39.     type: "Point"
  40.   },
  41.   properties: { hello: "world" }
  42. }
  43. */

flattenReduce

npm install @turf/meta

接收任意 GeoJSON 对象(包括要素集)，遍历累加操作。功能类似 Array.reduce()

值得注意的是，如果是多要素集，做扁平处理再遍历，功能类似 Array.flat()

参数

入参 类型 描述
geojson FeatureCollection\ Feature\ Geometry 任意 GeoJSON 对象
callback Function 回调，参数依次是 previousValue、currentFeature、featureIndex、multiFeatureIndex
initialValue (*) 初始值

返回

*

范例

  1. var features = turf.featureCollection([
  2.   turf.point([26, 37], { foo: "bar" }),
  3.   turf.multiPoint(
  4.     [
  5.       [40, 30],
  6.       [36, 53]
  7.     ],
  8.     { hello: "world" }
  9.   )
  10. ]);
  12. turf.flattenReduce(features, function (
  13.   previousValue,
  14.   currentFeature,
  15.   featureIndex,
  16.   multiFeatureIndex
  17. ) {
  18.   //=previousValue
  19.   //=currentFeature
  20.   //=featureIndex
  21.   //=multiFeatureIndex
  22.   return currentFeature;
  23. });

getCoord

npm install @turf/invariant

接收类型为 Point 的 GeoJSON，返回该要素的 coordinates 经纬度坐标

值得注意的是，如果入参是数组，只能是一维数组，否则抛出异常错误

参数

入参 类型 描述
coord Array\ Geometry<Point>\ Feature<Point> GeoJSON 或一维数组

返回

Array - coordinates

范例

  1. var pt = turf.point([10, 10]);
  3. var coord = turf.getCoord(pt);
  4. //= [10, 10]
  6. var pt2 = turf.getCoord([1, 2, 3, 4, 5]); // [1,2,3,4,5]

getCoords

npm install @turf/invariant

接收任意类型的 GeoJSON 或 Geometry，返回该要素的 coordinates 经纬度坐标

参数

入参 类型 描述
coords Array\ Feature\ Geometry 任意 GeoJSON 对象

返回

Array - coordinates

范例

  1. var poly = turf.polygon([
  2.   [
  3.     [119.32, -8.7],
  4.     [119.55, -8.69],
  5.     [119.51, -8.54],
  6.     [119.32, -8.7]
  7.   ]
  8. ]);
  10. var coords = turf.getCoords(poly);
  11. //= [[[119.32, -8.7], [119.55, -8.69], [119.51, -8.54], [119.32, -8.7]]]
  13. var coords2 = turf.getCoords({
  14.   // 也可以是Geometry
  15.   type: "LineString",
  16.   coordinates: [
  17.     [1, 2],
  18.     [3, 4]
  19.   ]
  20. }); // [[1,2], [3,4]]

getGeom

npm install @turf/invariant

接收任意类型的 GeoJSON，返回该要素的 Geometry

值得注意的是，如果不是 GeoJSON，该方法返回入参本身的值

参数

入参 类型 描述
geojson Feature\ Geometry 任意 GeoJSON 对象

返回

Geometry|AnyValue

范例

  1. var point = {
  2.   type: "Feature",
  3.   properties: {},
  4.   geometry: {
  5.     type: "Point",
  6.     coordinates: [110, 40]
  7.   }
  8. };
  9. var geom = turf.getGeom(point);
  10. //={"type": "Point", "coordinates": [110, 40]}
  12. turf.getGeom("wrong"); // 'wrong'

getType

npm install @turf/invariant

接收任意类型的 GeoJSON，返回该要素的类型

值得注意的是，如果是要素，返回类型优先是 Geometry 的 type，如果是要素集，返回类型优先是要素集的 type

参数

入参 类型 描述
geojson GeoJSON 任意 GeoJSON 对象
name String 在报错消息中展示的变量名，目前暂未使用

返回

string - GeoJSON type

范例

  1. var point = {
  2.   type: "Feature",
  3.   properties: {},
  4.   geometry: {
  5.     type: "Point",
  6.     coordinates: [110, 40]
  7.   }
  8. };
  9. var geom = turf.getType(point);
  10. //="Point"
  12. turf.getType({
  13.   type: "FeatureCollection",
  14.   faetures: [
  15.     {
  16.       type: "Feature",
  17.       geometry: {
  18.         type: "Point",
  19.         coordinates: [1, 2]
  20.       }
  21.     },
  22.     {
  23.       type: "Feature",
  24.       geometry: {
  25.         type: "LineString",
  26.         coordinates: [
  27.           [1, 2],
  28.           [3, 4]
  29.         ]
  30.       }
  31.     }
  32.   ]
  33. }); // "FeatureCollection"

geomEach

npm install @turf/meta

接收任意类型的 GeoJSON，遍历它的每个 Geometry。功能类似 Array.forEach()

参数

入参 类型 描述
geojson FeatureCollection\ Feature\ Geometry 任意 GeoJSON 对象
callback Function 回调，参数依次是 currentGeometry、featureIndex、featureProperties、featureBBox、featureId

返回

undefined

范例

  1. var features = turf.featureCollection([
  2.   turf.point([26, 37], { foo: "bar" }),
  3.   turf.point([36, 53], { hello: "world" })
  4. ]);
  6. turf.geomEach(features, function (
  7.   currentGeometry,
  8.   featureIndex,
  9.   featureProperties,
  10.   featureBBox,
  11.   featureId
  12. ) {
  13.   //=currentGeometry
  14.   //=featureIndex
  15.   //=featureProperties
  16.   //=featureBBox
  17.   //=featureId
  18. });

geomReduce

npm install @turf/meta

接收任意 GeoJSON 对象(包括要素集)，遍历它的每个 Geometry 并累加操作。功能类似 Array.reduce()

参数

入参 类型 描述
geojson FeatureCollection\ Feature\ Geometry 任意 GeoJSON 对象
callback Function 回调，参数依次是 previousValue、currentGeometry、featureIndex、featureProperties、featureBBox、featureId
initialValue (*) 初始值

返回

* - reduce 产生的值

范例

  1. var features = turf.featureCollection([
  2.   turf.point([26, 37], { foo: "bar" }),
  3.   turf.point([36, 53], { hello: "world" })
  4. ]);
  6. turf.geomReduce(features, function (
  7.   previousValue,
  8.   currentGeometry,
  9.   featureIndex,
  10.   featureProperties,
  11.   featureBBox,
  12.   featureId
  13. ) {
  14.   //=previousValue
  15.   //=currentGeometry
  16.   //=featureIndex
  17.   //=featureProperties
  18.   //=featureBBox
  19.   //=featureId
  20.   return currentGeometry;
  21. });

propEach

npm install @turf/meta

接收任意类型的 GeoJSON，遍历它的每个要素的 properties。功能类似 Array.forEach()

参数

入参 类型 描述
geojson FeatureCollection\ Feature 任意 GeoJSON 对象
callback Function 回调，参数依次是 currentProperties、featureIndex

返回

undefined

范例

  1. var features = turf.featureCollection([
  2.   turf.point([26, 37], { foo: "bar" }),
  3.   turf.point([36, 53], { hello: "world" })
  4. ]);
  6. turf.propEach(features, function (currentProperties, featureIndex) {
  7.   //=currentProperties
  8.   //=featureIndex
  9. });

propReduce

npm install @turf/meta

接收任意类型的 GeoJSON，遍历它的每个要素的 properties 并累加操作。功能类似 Array.reduce()

参数

入参 类型 描述
geojson FeatureCollection\ Feature 任意 GeoJSON 对象
callback Function 回调，参数依次是 previousValue、currentProperties、featureIndex
initialValue (*) 初始值

返回

* - reduce 产生的值

范例

  1. var features = turf.featureCollection([
  2.   turf.point([26, 37], { foo: "bar" }),
  3.   turf.point([36, 53], { hello: "world" })
  4. ]);
  6. turf.propReduce(features, function (previousValue, currentProperties, featureIndex) {
  7.   //=previousValue
  8.   console.log(currentProperties);
  9.   //=featureIndex
  10.   return currentProperties;
  11. });
  12. /*
  13.   { foo: "bar" }
  14.   { hello: "world" }
  15. */

segmentEach

npm install @turf/meta

接收任意类型的 GeoJSON，遍历它的 2-vertex 线段。功能类似 Array.forEach()

值得注意的是，(Multi)Point 的要素不包含线段，不进行操作

参数

入参 类型 描述
geojson FeatureCollection\ Feature\ Geometry 任意 GeoJSON 对象
callback Function 回调，参数依次是 currentSegment、featureIndex、multiFeatureIndex、geometryIndex、segmentIndex

返回

undefined

范例

  1. var polygon = turf.polygon([
  2.   [
  3.     [-50, 5],
  4.     [-40, -10],
  5.     [-50, -10],
  6.     [-40, 5],
  7.     [-50, 5]
  8.   ]
  9. ]);
  11. // Iterate over GeoJSON by 2-vertex segments
  12. turf.segmentEach(polygon, function (
  13.   currentSegment,
  14.   featureIndex,
  15.   multiFeatureIndex,
  16.   geometryIndex,
  17.   segmentIndex
  18. ) {
  19.   //=currentSegment
  20.   //=featureIndex
  21.   //=multiFeatureIndex
  22.   //=geometryIndex
  23.   //=segmentIndex
  24. });
  26. // Calculate the total number of segments
  27. var total = 0;
  28. turf.segmentEach(polygon, function () {
  29.   total++;
  30. });

segmentReduce

npm install @turf/meta

接收任意类型的 GeoJSON，遍历它的 2-vertex 线段并累加操作。功能类似 Array.reduce()

参数

入参 类型 描述
geojson FeatureCollection\ Feature\ Geometry 任意 GeoJSON 对象
callback Function 回调，参数依次是 previousValue、currentProperties、featureIndex
initialValue (*) 初始值

返回

undefined

范例

  1. var polygon = turf.polygon([
  2.   [
  3.     [-50, 5],
  4.     [-40, -10],
  5.     [-50, -10],
  6.     [-40, 5],
  7.     [-50, 5]
  8.   ]
  9. ]);
  11. // Iterate over GeoJSON by 2-vertex segments
  12. turf.segmentReduce(polygon, function (
  13.   previousSegment,
  14.   currentSegment,
  15.   featureIndex,
  16.   multiFeatureIndex,
  17.   geometryIndex,
  18.   segmentIndex
  19. ) {
  20.   //= previousSegment
  21.   //= currentSegment
  22.   //= featureIndex
  23.   //= multiFeatureIndex
  24.   //= geometryIndex
  25.   //= segmentInex
  26.   return currentSegment;
  27. });
  29. // Calculate the total number of segments
  30. var initialValue = 0;
  31. var total = turf.segmentReduce(
  32.   polygon,
  33.   function (previousValue) {
  34.     previousValue++;
  35.     return previousValue;
  36.   },
  37.   initialValue
  38. );

getCluster

npm install @turf/clusters

接收要素集FeatureCollection，过滤指定属性的要素并返回要素集

参数

入参 类型 描述
geojson FeatureCollection GeoJSON 要素集
filter (*) 初始值

返回

FeatureCollection - 过滤后的要素集

范例

  1. var geojson = turf.featureCollection([
  2.   turf.point([0, 0], { "marker-symbol": "circle" }),
  3.   turf.point([2, 4], { "marker-symbol": "star" }),
  4.   turf.point([3, 6], { "marker-symbol": "star" }),
  5.   turf.point([5, 1], { "marker-symbol": "square" }),
  6.   turf.point([4, 2], { "marker-symbol": "circle" })
  7. ]);
  9. // Create a cluster using K-Means (adds `cluster` to GeoJSON properties)
  10. var clustered = turf.clustersKmeans(geojson);
  12. // Retrieve first cluster (0)
  13. var cluster = turf.getCluster(clustered, { cluster: 0 });
  14. //= cluster
  16. // Retrieve cluster based on custom properties
  17. turf.getCluster(clustered, { "marker-symbol": "circle" }).length;
  18. //= 2
  19. turf.getCluster(clustered, { "marker-symbol": "square" }).length;
  20. //= 1

clusterEach

npm install @turf/clusters

接收要素集FeatureCollection，遍历通过指定属性过滤后的要素集集群

参数

入参 类型 描述
geojson FeatureCollection GeoJSON 要素集
property String\ Number 用于过滤、区分要素集的属性值
callback Function 回调，参数依次是 previousValue、currentProperties、featureIndex

返回

undefined

范例

  1. var geojson = turf.featureCollection([
  2.   turf.point([0, 0]),
  3.   turf.point([2, 4]),
  4.   turf.point([3, 6]),
  5.   turf.point([5, 1]),
  6.   turf.point([4, 2])
  7. ]);
  9. // Create a cluster using K-Means (adds `cluster` to GeoJSON properties)
  10. var clustered = turf.clustersKmeans(geojson); // cluster为0有1个要素，cluster为1有4个要素
  12. // Iterate over each cluster
  13. turf.clusterEach(clustered, "cluster", function (cluster, clusterValue, currentIndex) {
  14.   //= cluster
  15.   //= clusterValue
  16.   //= currentIndex
  17.   console.log("cluster: ", cluster, clusterValue);
  18. });
  19. /*
  20.   cluster: { type: "FeatureCollection", features: Array(1) }, "0"
  21.   cluster: { type: "FeatureCollection", features: Array(4) }, "1"
  22. */
  24. // Calculate the total number of clusters
  25. var total = 0;
  26. turf.clusterEach(clustered, "cluster", function () {
  27.   total++;
  28. });
  30. // Create an Array of all the values retrieved from the 'cluster' property
  31. var values = [];
  32. turf.clusterEach(clustered, "cluster", function (cluster, clusterValue) {
  33.   values.push(clusterValue);
  34. });

clusterReduce

npm install @turf/meta

接收要素集FeatureCollection，遍历通过指定属性过滤后的要素集集群并累加操作

参数

入参 类型 描述
geojson FeatureCollection GeoJSON 要素集
property String\ Number 用于过滤、区分要素集的属性值
callback Function 回调，参数依次是 previousValue、cluster、clusterValue、currentIndex
initialValue (*) 初始值

返回

* - reduce 产生的值

范例

  1. var geojson = turf.featureCollection([
  2.   turf.point([0, 0]),
  3.   turf.point([2, 4]),
  4.   turf.point([3, 6]),
  5.   turf.point([5, 1]),
  6.   turf.point([4, 2])
  7. ]);
  9. // Create a cluster using K-Means (adds `cluster` to GeoJSON properties)
  10. var clustered = turf.clustersKmeans(geojson);
  12. // Iterate over each cluster and perform a calculation
  13. var initialValue = 0;
  14. turf.clusterReduce(
  15.   clustered,
  16.   "cluster",
  17.   function (previousValue, cluster, clusterValue, currentIndex) {
  18.     //=previousValue
  19.     //=cluster
  20.     //=clusterValue
  21.     //=currentIndex
  22.     return previousValue++;
  23.   },
  24.   initialValue
  25. );
  27. // Calculate the total number of clusters
  28. var total = turf.clusterReduce(
  29.   clustered,
  30.   "cluster",
  31.   function (previousValue) {
  32.     return previousValue++;
  33.   },
  34.   0
  35. );
  37. // Create an Array of all the values retrieved from the 'cluster' property
  38. var values = turf.clusterReduce(
  39.   clustered,
  40.   "cluster",
  41.   function (previousValue, cluster, clusterValue) {
  42.     return previousValue.concat(clusterValue);
  43.   },
  44.   []
  45. );