@turf/meta
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    @turf/meta

    coordEachCallback

    Callback for coordEach

    Type: Function

    Parameters

    • currentCoord Array<number> The current coordinate being processed.
    • coordIndex number The current index of the coordinate being processed.
    • featureIndex number The current index of the Feature being processed.
    • multiFeatureIndex number The current index of the Multi-Feature being processed.
    • geometryIndex number The current index of the Geometry being processed.

    coordEach

    Iterate over coordinates in any GeoJSON object, similar to Array.forEach()

    Parameters

    • geojson (FeatureCollection | Feature | Geometry) any GeoJSON object
    • callback Function a method that takes (currentCoord, coordIndex, featureIndex, multiFeatureIndex)
    • excludeWrapCoord boolean whether or not to include the final coordinate of LinearRings that wraps the ring in its iteration. (optional, default false)

    Examples

    var features = turf.featureCollection([
      turf.point([26, 37], {"foo": "bar"}),
      turf.point([36, 53], {"hello": "world"})
    ]);
    
    turf.coordEach(features, function (currentCoord, coordIndex, featureIndex, multiFeatureIndex, geometryIndex) {
      //=currentCoord
      //=coordIndex
      //=featureIndex
      //=multiFeatureIndex
      //=geometryIndex
    });

    Returns void

    coordReduce

    Reduce coordinates in any GeoJSON object, similar to Array.reduce()

    Parameters

    • geojson (FeatureCollection | Geometry | Feature) any GeoJSON object
    • callback Function a method that takes (previousValue, currentCoord, coordIndex)
    • initialValue any? Value to use as the first argument to the first call of the callback.
    • excludeWrapCoord boolean whether or not to include the final coordinate of LinearRings that wraps the ring in its iteration. (optional, default false)

    Examples

    var features = turf.featureCollection([
      turf.point([26, 37], {"foo": "bar"}),
      turf.point([36, 53], {"hello": "world"})
    ]);
    
    turf.coordReduce(features, function (previousValue, currentCoord, coordIndex, featureIndex, multiFeatureIndex, geometryIndex) {
      //=previousValue
      //=currentCoord
      //=coordIndex
      //=featureIndex
      //=multiFeatureIndex
      //=geometryIndex
      return currentCoord;
    });

    Returns any The value that results from the reduction.

    coordReduceCallback

    Callback for coordReduce

    The first time the callback function is called, the values provided as arguments depend on whether the reduce method has an initialValue argument.

    If an initialValue is provided to the reduce method:

    • The previousValue argument is initialValue.
    • The currentValue argument is the value of the first element present in the array.

    If an initialValue is not provided:

    • The previousValue argument is the value of the first element present in the array.
    • The currentValue argument is the value of the second element present in the array.

    Type: Function

    Parameters

    • previousValue any The accumulated value previously returned in the last invocation of the callback, or initialValue, if supplied.
    • currentCoord Array<number> The current coordinate being processed.
    • coordIndex number The current index of the coordinate being processed. Starts at index 0, if an initialValue is provided, and at index 1 otherwise.
    • featureIndex number The current index of the Feature being processed.
    • multiFeatureIndex number The current index of the Multi-Feature being processed.
    • geometryIndex number The current index of the Geometry being processed.

    propEach

    Iterate over properties in any GeoJSON object, similar to Array.forEach()

    Parameters

    Examples

    var features = turf.featureCollection([
        turf.point([26, 37], {foo: 'bar'}),
        turf.point([36, 53], {hello: 'world'})
    ]);
    
    turf.propEach(features, function (currentProperties, featureIndex) {
      //=currentProperties
      //=featureIndex
    });

    Returns void

    propEachCallback

    Callback for propEach

    Type: Function

    Parameters

    • currentProperties Object The current Properties being processed.
    • featureIndex number The current index of the Feature being processed.

    propReduceCallback

    Callback for propReduce

    The first time the callback function is called, the values provided as arguments depend on whether the reduce method has an initialValue argument.

    If an initialValue is provided to the reduce method:

    • The previousValue argument is initialValue.
    • The currentValue argument is the value of the first element present in the array.

    If an initialValue is not provided:

    • The previousValue argument is the value of the first element present in the array.
    • The currentValue argument is the value of the second element present in the array.

    Type: Function

    Parameters

    • previousValue any The accumulated value previously returned in the last invocation of the callback, or initialValue, if supplied.
    • currentProperties any The current Properties being processed.
    • featureIndex number The current index of the Feature being processed.

    propReduce

    Reduce properties in any GeoJSON object into a single value, similar to how Array.reduce works. However, in this case we lazily run the reduction, so an array of all properties is unnecessary.

    Parameters

    • geojson (FeatureCollection | Feature) any GeoJSON object
    • callback Function a method that takes (previousValue, currentProperties, featureIndex)
    • initialValue any? Value to use as the first argument to the first call of the callback.

    Examples

    var features = turf.featureCollection([
        turf.point([26, 37], {foo: 'bar'}),
        turf.point([36, 53], {hello: 'world'})
    ]);
    
    turf.propReduce(features, function (previousValue, currentProperties, featureIndex) {
      //=previousValue
      //=currentProperties
      //=featureIndex
      return currentProperties
    });

    Returns any The value that results from the reduction.

    featureEachCallback

    Callback for featureEach

    Type: Function

    Parameters

    • currentFeature Feature<any> The current Feature being processed.
    • featureIndex number The current index of the Feature being processed.

    featureEach

    Iterate over features in any GeoJSON object, similar to Array.forEach.

    Parameters

    Examples

    var features = turf.featureCollection([
      turf.point([26, 37], {foo: 'bar'}),
      turf.point([36, 53], {hello: 'world'})
    ]);
    
    turf.featureEach(features, function (currentFeature, featureIndex) {
      //=currentFeature
      //=featureIndex
    });

    Returns void

    featureReduceCallback

    Callback for featureReduce

    The first time the callback function is called, the values provided as arguments depend on whether the reduce method has an initialValue argument.

    If an initialValue is provided to the reduce method:

    • The previousValue argument is initialValue.
    • The currentValue argument is the value of the first element present in the array.

    If an initialValue is not provided:

    • The previousValue argument is the value of the first element present in the array.
    • The currentValue argument is the value of the second element present in the array.

    Type: Function

    Parameters

    • previousValue any The accumulated value previously returned in the last invocation of the callback, or initialValue, if supplied.
    • currentFeature Feature The current Feature being processed.
    • featureIndex number The current index of the Feature being processed.

    featureReduce

    Reduce features in any GeoJSON object, similar to Array.reduce().

    Parameters

    • geojson (FeatureCollection | Feature | Geometry) any GeoJSON object
    • callback Function a method that takes (previousValue, currentFeature, featureIndex)
    • initialValue any? Value to use as the first argument to the first call of the callback.

    Examples

    var features = turf.featureCollection([
      turf.point([26, 37], {"foo": "bar"}),
      turf.point([36, 53], {"hello": "world"})
    ]);
    
    turf.featureReduce(features, function (previousValue, currentFeature, featureIndex) {
      //=previousValue
      //=currentFeature
      //=featureIndex
      return currentFeature
    });

    Returns any The value that results from the reduction.

    coordAll

    Get all coordinates from any GeoJSON object.

    Parameters

    Examples

    var features = turf.featureCollection([
      turf.point([26, 37], {foo: 'bar'}),
      turf.point([36, 53], {hello: 'world'})
    ]);
    
    var coords = turf.coordAll(features);
    //= [[26, 37], [36, 53]]

    Returns Array<Array<number>> coordinate position array

    geomEachCallback

    Callback for geomEach

    Type: Function

    Parameters

    • currentGeometry Geometry The current Geometry being processed.
    • featureIndex number The current index of the Feature being processed.
    • featureProperties Object The current Feature Properties being processed.
    • featureBBox Array<number> The current Feature BBox being processed.
    • featureId (number | string) The current Feature Id being processed.

    geomEach

    Iterate over each geometry in any GeoJSON object, similar to Array.forEach()

    Parameters

    Examples

    var features = turf.featureCollection([
        turf.point([26, 37], {foo: 'bar'}),
        turf.point([36, 53], {hello: 'world'})
    ]);
    
    turf.geomEach(features, function (currentGeometry, featureIndex, featureProperties, featureBBox, featureId) {
      //=currentGeometry
      //=featureIndex
      //=featureProperties
      //=featureBBox
      //=featureId
    });

    Returns void

    geomReduceCallback

    Callback for geomReduce

    The first time the callback function is called, the values provided as arguments depend on whether the reduce method has an initialValue argument.

    If an initialValue is provided to the reduce method:

    • The previousValue argument is initialValue.
    • The currentValue argument is the value of the first element present in the array.

    If an initialValue is not provided:

    • The previousValue argument is the value of the first element present in the array.
    • The currentValue argument is the value of the second element present in the array.

    Type: Function

    Parameters

    • previousValue any The accumulated value previously returned in the last invocation of the callback, or initialValue, if supplied.
    • currentGeometry Geometry The current Geometry being processed.
    • featureIndex number The current index of the Feature being processed.
    • featureProperties Object The current Feature Properties being processed.
    • featureBBox Array<number> The current Feature BBox being processed.
    • featureId (number | string) The current Feature Id being processed.

    geomReduce

    Reduce geometry in any GeoJSON object, similar to Array.reduce().

    Parameters

    • geojson (FeatureCollection | Feature | Geometry) any GeoJSON object
    • callback Function a method that takes (previousValue, currentGeometry, featureIndex, featureProperties, featureBBox, featureId)
    • initialValue any? Value to use as the first argument to the first call of the callback.

    Examples

    var features = turf.featureCollection([
        turf.point([26, 37], {foo: 'bar'}),
        turf.point([36, 53], {hello: 'world'})
    ]);
    
    turf.geomReduce(features, function (previousValue, currentGeometry, featureIndex, featureProperties, featureBBox, featureId) {
      //=previousValue
      //=currentGeometry
      //=featureIndex
      //=featureProperties
      //=featureBBox
      //=featureId
      return currentGeometry
    });

    Returns any The value that results from the reduction.

    flattenEachCallback

    Callback for flattenEach

    Type: Function

    Parameters

    • currentFeature Feature The current flattened feature being processed.
    • featureIndex number The current index of the Feature being processed.
    • multiFeatureIndex number The current index of the Multi-Feature being processed.

    flattenEach

    Iterate over flattened features in any GeoJSON object, similar to Array.forEach.

    Parameters

    Examples

    var features = turf.featureCollection([
        turf.point([26, 37], {foo: 'bar'}),
        turf.multiPoint([[40, 30], [36, 53]], {hello: 'world'})
    ]);
    
    turf.flattenEach(features, function (currentFeature, featureIndex, multiFeatureIndex) {
      //=currentFeature
      //=featureIndex
      //=multiFeatureIndex
    });

    flattenReduceCallback

    Callback for flattenReduce

    The first time the callback function is called, the values provided as arguments depend on whether the reduce method has an initialValue argument.

    If an initialValue is provided to the reduce method:

    • The previousValue argument is initialValue.
    • The currentValue argument is the value of the first element present in the array.

    If an initialValue is not provided:

    • The previousValue argument is the value of the first element present in the array.
    • The currentValue argument is the value of the second element present in the array.

    Type: Function

    Parameters

    • previousValue any The accumulated value previously returned in the last invocation of the callback, or initialValue, if supplied.
    • currentFeature Feature The current Feature being processed.
    • featureIndex number The current index of the Feature being processed.
    • multiFeatureIndex number The current index of the Multi-Feature being processed.

    flattenReduce

    Reduce flattened features in any GeoJSON object, similar to Array.reduce().

    Parameters

    • geojson (FeatureCollection | Feature | Geometry) any GeoJSON object
    • callback Function a method that takes (previousValue, currentFeature, featureIndex, multiFeatureIndex)
    • initialValue any? Value to use as the first argument to the first call of the callback.

    Examples

    var features = turf.featureCollection([
        turf.point([26, 37], {foo: 'bar'}),
        turf.multiPoint([[40, 30], [36, 53]], {hello: 'world'})
    ]);
    
    turf.flattenReduce(features, function (previousValue, currentFeature, featureIndex, multiFeatureIndex) {
      //=previousValue
      //=currentFeature
      //=featureIndex
      //=multiFeatureIndex
      return currentFeature
    });

    Returns any The value that results from the reduction.

    segmentEachCallback

    Callback for segmentEach

    Type: Function

    Parameters

    • currentSegment Feature<LineString> The current Segment being processed.
    • featureIndex number The current index of the Feature being processed.
    • multiFeatureIndex number The current index of the Multi-Feature being processed.
    • geometryIndex number The current index of the Geometry being processed.
    • segmentIndex number The current index of the Segment being processed.

    Returns void

    segmentEach

    Iterate over 2-vertex line segment in any GeoJSON object, similar to Array.forEach() (Multi)Point geometries do not contain segments therefore they are ignored during this operation.

    Parameters

    Examples

    var polygon = turf.polygon([[[-50, 5], [-40, -10], [-50, -10], [-40, 5], [-50, 5]]]);
    
    // Iterate over GeoJSON by 2-vertex segments
    turf.segmentEach(polygon, function (currentSegment, featureIndex, multiFeatureIndex, geometryIndex, segmentIndex) {
      //=currentSegment
      //=featureIndex
      //=multiFeatureIndex
      //=geometryIndex
      //=segmentIndex
    });
    
    // Calculate the total number of segments
    var total = 0;
    turf.segmentEach(polygon, function () {
        total++;
    });

    Returns void

    segmentReduceCallback

    Callback for segmentReduce

    The first time the callback function is called, the values provided as arguments depend on whether the reduce method has an initialValue argument.

    If an initialValue is provided to the reduce method:

    • The previousValue argument is initialValue.
    • The currentValue argument is the value of the first element present in the array.

    If an initialValue is not provided:

    • The previousValue argument is the value of the first element present in the array.
    • The currentValue argument is the value of the second element present in the array.

    Type: Function

    Parameters

    • previousValue any The accumulated value previously returned in the last invocation of the callback, or initialValue, if supplied.
    • currentSegment Feature<LineString> The current Segment being processed.
    • featureIndex number The current index of the Feature being processed.
    • multiFeatureIndex number The current index of the Multi-Feature being processed.
    • geometryIndex number The current index of the Geometry being processed.
    • segmentIndex number The current index of the Segment being processed.

    segmentReduce

    Reduce 2-vertex line segment in any GeoJSON object, similar to Array.reduce() (Multi)Point geometries do not contain segments therefore they are ignored during this operation.

    Parameters

    • geojson (FeatureCollection | Feature | Geometry) any GeoJSON
    • callback Function a method that takes (previousValue, currentSegment, currentIndex)
    • initialValue any? Value to use as the first argument to the first call of the callback.

    Examples

    var polygon = turf.polygon([[[-50, 5], [-40, -10], [-50, -10], [-40, 5], [-50, 5]]]);
    
    // Iterate over GeoJSON by 2-vertex segments
    turf.segmentReduce(polygon, function (previousSegment, currentSegment, featureIndex, multiFeatureIndex, geometryIndex, segmentIndex) {
      //= previousSegment
      //= currentSegment
      //= featureIndex
      //= multiFeatureIndex
      //= geometryIndex
      //= segmentInex
      return currentSegment
    });
    
    // Calculate the total number of segments
    var initialValue = 0
    var total = turf.segmentReduce(polygon, function (previousValue) {
        previousValue++;
        return previousValue;
    }, initialValue);

    Returns void

    lineEachCallback

    Callback for lineEach

    Type: Function

    Parameters

    • currentLine Feature<LineString> The current LineString|LinearRing being processed
    • featureIndex number The current index of the Feature being processed
    • multiFeatureIndex number The current index of the Multi-Feature being processed
    • geometryIndex number The current index of the Geometry being processed

    lineEach

    Iterate over line or ring coordinates in LineString, Polygon, MultiLineString, MultiPolygon Features or Geometries, similar to Array.forEach.

    Parameters

    Examples

    var multiLine = turf.multiLineString([
      [[26, 37], [35, 45]],
      [[36, 53], [38, 50], [41, 55]]
    ]);
    
    turf.lineEach(multiLine, function (currentLine, featureIndex, multiFeatureIndex, geometryIndex) {
      //=currentLine
      //=featureIndex
      //=multiFeatureIndex
      //=geometryIndex
    });

    lineReduceCallback

    Callback for lineReduce

    The first time the callback function is called, the values provided as arguments depend on whether the reduce method has an initialValue argument.

    If an initialValue is provided to the reduce method:

    • The previousValue argument is initialValue.
    • The currentValue argument is the value of the first element present in the array.

    If an initialValue is not provided:

    • The previousValue argument is the value of the first element present in the array.
    • The currentValue argument is the value of the second element present in the array.

    Type: Function

    Parameters

    • previousValue any The accumulated value previously returned in the last invocation of the callback, or initialValue, if supplied.
    • currentLine Feature<LineString> The current LineString|LinearRing being processed.
    • featureIndex number The current index of the Feature being processed
    • multiFeatureIndex number The current index of the Multi-Feature being processed
    • geometryIndex number The current index of the Geometry being processed

    lineReduce

    Reduce features in any GeoJSON object, similar to Array.reduce().

    Parameters

    Examples

    var multiPoly = turf.multiPolygon([
      turf.polygon([[[12,48],[2,41],[24,38],[12,48]], [[9,44],[13,41],[13,45],[9,44]]]),
      turf.polygon([[[5, 5], [0, 0], [2, 2], [4, 4], [5, 5]]])
    ]);
    
    turf.lineReduce(multiPoly, function (previousValue, currentLine, featureIndex, multiFeatureIndex, geometryIndex) {
      //=previousValue
      //=currentLine
      //=featureIndex
      //=multiFeatureIndex
      //=geometryIndex
      return currentLine
    });

    Returns any The value that results from the reduction.

    findSegment

    Finds a particular 2-vertex LineString Segment from a GeoJSON using @turf/meta indexes.

    Negative indexes are permitted. Point & MultiPoint will always return null.

    Parameters

    • geojson (FeatureCollection | Feature | Geometry) Any GeoJSON Feature or Geometry
    • options Object Optional parameters (optional, default {})
      • options.featureIndex number Feature Index (optional, default 0)
      • options.multiFeatureIndex number Multi-Feature Index (optional, default 0)
      • options.geometryIndex number Geometry Index (optional, default 0)
      • options.segmentIndex number Segment Index (optional, default 0)
      • options.properties Object Translate Properties to output LineString (optional, default {})
      • options.bbox BBox Translate BBox to output LineString (optional, default {})
      • options.id (number | string) Translate Id to output LineString (optional, default {})

    Examples

    var multiLine = turf.multiLineString([
        [[10, 10], [50, 30], [30, 40]],
        [[-10, -10], [-50, -30], [-30, -40]]
    ]);
    
    // First Segment (defaults are 0)
    turf.findSegment(multiLine);
    // => Feature<LineString<[[10, 10], [50, 30]]>>
    
    // First Segment of 2nd Multi Feature
    turf.findSegment(multiLine, {multiFeatureIndex: 1});
    // => Feature<LineString<[[-10, -10], [-50, -30]]>>
    
    // Last Segment of Last Multi Feature
    turf.findSegment(multiLine, {multiFeatureIndex: -1, segmentIndex: -1});
    // => Feature<LineString<[[-50, -30], [-30, -40]]>>

    Returns Feature<LineString> 2-vertex GeoJSON Feature LineString

    findPoint

    Finds a particular Point from a GeoJSON using @turf/meta indexes.

    Negative indexes are permitted.

    Parameters

    • geojson (FeatureCollection | Feature | Geometry) Any GeoJSON Feature or Geometry
    • options Object Optional parameters (optional, default {})
      • options.featureIndex number Feature Index (optional, default 0)
      • options.multiFeatureIndex number Multi-Feature Index (optional, default 0)
      • options.geometryIndex number Geometry Index (optional, default 0)
      • options.coordIndex number Coord Index (optional, default 0)
      • options.properties Object Translate Properties to output Point (optional, default {})
      • options.bbox BBox Translate BBox to output Point (optional, default {})
      • options.id (number | string) Translate Id to output Point (optional, default {})

    Examples

    var multiLine = turf.multiLineString([
        [[10, 10], [50, 30], [30, 40]],
        [[-10, -10], [-50, -30], [-30, -40]]
    ]);
    
    // First Segment (defaults are 0)
    turf.findPoint(multiLine);
    // => Feature<Point<[10, 10]>>
    
    // First Segment of the 2nd Multi-Feature
    turf.findPoint(multiLine, {multiFeatureIndex: 1});
    // => Feature<Point<[-10, -10]>>
    
    // Last Segment of last Multi-Feature
    turf.findPoint(multiLine, {multiFeatureIndex: -1, coordIndex: -1});
    // => Feature<Point<[-30, -40]>>

    Returns Feature<Point> 2-vertex GeoJSON Feature Point


    This module is part of the Turfjs project, an open source module collection dedicated to geographic algorithms. It is maintained in the Turfjs/turf repository, where you can create PRs and issues.

    Installation

    Install this module individually:

    $ npm install @turf/meta

    Or install the Turf module that includes it as a function:

    $ npm install @turf/turf

    Install

    npm i @turf/meta

    DownloadsWeekly Downloads

    691,442

    Version

    6.5.0

    License

    MIT

    Unpacked Size

    134 kB

    Total Files

    7

    Last publish

    Collaborators

    • rowanwins
    • tmcw
    • morganherlocker
    • tcql
    • deniscarriere
    • mdfedderly