$ npm install @turf/meta
Callback for coordEach
Type: Function
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.Iterate over coordinates in any GeoJSON object, similar to Array.forEach()
geojson
(FeatureCollection | Feature | Geometry) any GeoJSON objectcallback
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
)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
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:
If an initialValue is not provided:
Type: Function
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.Reduce coordinates in any GeoJSON object, similar to Array.reduce()
geojson
(FeatureCollection | Geometry | Feature) any GeoJSON objectcallback
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
)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.
Callback for propEach
Type: Function
currentProperties
Object The current Properties being processed.featureIndex
number The current index of the Feature being processed.Iterate over properties in any GeoJSON object, similar to Array.forEach()
geojson
(FeatureCollection | Feature) any GeoJSON objectcallback
Function a method that takes (currentProperties, featureIndex)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
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:
If an initialValue is not provided:
Type: Function
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.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.
geojson
(FeatureCollection | Feature) any GeoJSON objectcallback
Function a method that takes (previousValue, currentProperties, featureIndex)initialValue
any? Value to use as the first argument to the first call of the callback.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.
Callback for featureEach
Type: Function
currentFeature
Feature<any> The current Feature being processed.featureIndex
number The current index of the Feature being processed.Iterate over features in any GeoJSON object, similar to Array.forEach.
geojson
(FeatureCollection | Feature | Geometry) any GeoJSON objectcallback
Function a method that takes (currentFeature, featureIndex)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
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:
If an initialValue is not provided:
Type: Function
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.Reduce features in any GeoJSON object, similar to Array.reduce().
geojson
(FeatureCollection | Feature | Geometry) any GeoJSON objectcallback
Function a method that takes (previousValue, currentFeature, featureIndex)initialValue
any? Value to use as the first argument to the first call of the callback.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.
Get all coordinates from any GeoJSON object.
geojson
(FeatureCollection | Feature | Geometry) any GeoJSON objectvar 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
Callback for geomEach
Type: Function
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.Iterate over each geometry in any GeoJSON object, similar to Array.forEach()
geojson
(FeatureCollection | Feature | Geometry) any GeoJSON objectcallback
Function a method that takes (currentGeometry, featureIndex, featureProperties, featureBBox, featureId)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
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:
If an initialValue is not provided:
Type: Function
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.Reduce geometry in any GeoJSON object, similar to Array.reduce().
geojson
(FeatureCollection | Feature | Geometry) any GeoJSON objectcallback
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.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.
Callback for flattenEach
Type: Function
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.Iterate over flattened features in any GeoJSON object, similar to Array.forEach.
geojson
(FeatureCollection | Feature | Geometry) any GeoJSON objectcallback
Function a method that takes (currentFeature, featureIndex, multiFeatureIndex)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
});
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:
If an initialValue is not provided:
Type: Function
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.Reduce flattened features in any GeoJSON object, similar to Array.reduce().
geojson
(FeatureCollection | Feature | Geometry) any GeoJSON objectcallback
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.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.
Callback for segmentEach
Type: Function
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
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.
geojson
(FeatureCollection | Feature | Geometry) any GeoJSONcallback
Function a method that takes (currentSegment, featureIndex, multiFeatureIndex, geometryIndex, segmentIndex)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
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:
If an initialValue is not provided:
Type: Function
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.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.
geojson
(FeatureCollection | Feature | Geometry) any GeoJSONcallback
Function a method that takes (previousValue, currentSegment, currentIndex)initialValue
any? Value to use as the first argument to the first call of the callback.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
//= segmentIndex
return currentSegment
});
// Calculate the total number of segments
var initialValue = 0
var total = turf.segmentReduce(polygon, function (previousValue) {
previousValue++;
return previousValue;
}, initialValue);
Returns void
Callback for lineEach
Type: Function
currentLine
Feature<LineString> The current LineString|LinearRing being processedfeatureIndex
number The current index of the Feature being processedmultiFeatureIndex
number The current index of the Multi-Feature being processedgeometryIndex
number The current index of the Geometry being processedIterate over line or ring coordinates in LineString, Polygon, MultiLineString, MultiPolygon Features or Geometries, similar to Array.forEach.
geojson
(Geometry | Feature<(LineString | Polygon | MultiLineString | MultiPolygon)>) objectcallback
Function a method that takes (currentLine, featureIndex, multiFeatureIndex, geometryIndex)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
});
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:
If an initialValue is not provided:
Type: Function
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 processedmultiFeatureIndex
number The current index of the Multi-Feature being processedgeometryIndex
number The current index of the Geometry being processedReduce features in any GeoJSON object, similar to Array.reduce().
geojson
(Geometry | Feature<(LineString | Polygon | MultiLineString | MultiPolygon)>) objectcallback
Function a method that takes (previousValue, currentLine, featureIndex, multiFeatureIndex, geometryIndex)initialValue
any? Value to use as the first argument to the first call of the callback.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.
Finds a particular 2-vertex LineString Segment from a GeoJSON using @turf/meta
indexes.
Negative indexes are permitted. Point & MultiPoint will always return null.
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 {}
)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
Finds a particular Point from a GeoJSON using @turf/meta
indexes.
Negative indexes are permitted.
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 {}
)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.
Install this single module individually:
$ npm install @turf/meta
Or install the all-encompassing @turf/turf module that includes all modules as functions:
$ npm install @turf/turf
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