@turf/nearest-neighbor-analysis
Advanced tools
Nearest Neighbor Analysis calculates an index based the average distances between points in the dataset, thereby providing inference as to whether the data is clustered, dispersed, or randomly distributed within the study area.
It returns a Feature<Polygon> of the study area, with the results of
the analysis attached as part of of the nearestNeighborAnalysis property
of the study area's properties. The attached
z-score indicates how many
standard deviations above or below the expected mean distance the data's
observed mean distance is. The more negative, the more clustered. The more
positive, the more evenly dispersed. A z-score between -2 and 2 indicates
a seemingly random distribution. That is, within p of less than 0.05, the
distribution appears statistically significantly neither clustered nor
dispersed.
Remarks
Though the analysis will work on any FeatureCollection type, it works best with Point collections.
This analysis is very sensitive to the study area provided. If no Feature<Polygon> is passed as the study area, the function draws a box around the data, which may distort the findings. This analysis works best with a bounded area of interest within with the data is either clustered, dispersed, or randomly distributed. For example, a city's subway stops may look extremely clustered if the study area is an entire state. On the other hand, they may look rather evenly dispersed if the study area is limited to the city's downtown.
Bibliography
Philip J. Clark and Francis C. Evans, “Distance to Nearest Neighbor as a Measure of Spatial Relationships in Populations,” Ecology 35, no. 4 (1954): 445–453, doi:10.2307/1931034.
Parameters
dataset FeatureCollection<any> FeatureCollection (pref. of points) to studyoptions Object Optional parameters (optional, default {})
Examples
var bbox = [-65, 40, -63, 42];
var dataset = turf.randomPoint(100, { bbox: bbox });
var nearestNeighborStudyArea = turf.nearestNeighborAnalysis(dataset);
//addToMap
var addToMap = [dataset, nearestNeighborStudyArea];
Returns Feature<Polygon> A polygon of the study area or an approximation of one.
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 module individually:
$ npm install @turf/nearest-neighbor-analysis
Or install the Turf module that includes it as a function:
$ npm install @turf/turf
6.2.0
After a bit of hiatus, TurfJS is resuming releases.
@turf/boolean-touches][boolean-touches]Determines if two features touch but do not intersect
@turf/boolean-valid][boolean-valid]Checks if the geometry is a valid according to the OGC Simple Feature Specification
@turf/quadrat-analysis][quadrat-analysis]Performs a quadrat analysis on a set of points
@turf/rectangle-grid][rectangle-grid]Creates a grid of rectangles from a bounding box
@turf/voroni][voronoi]Typescript types for the options parameter have been fixed (PR https://github.com/Turfjs/turf/pull/1424 - Author @stevage)
@turf/points-within-polygon][points-within-polygon]Typescript types around the Feature's Properties will now be preserved. (PR https://github.com/Turfjs/turf/pull/1761 - Author @rugheid)
@turf/rewind][rewind]Typescript types for the 'reverse' option are now correct. Previously it was misnamed as 'reversed'. (PR https://github.com/Turfjs/turf/pull/1786 - Author @jonnycornwell)
@turf/difference][difference]No longer publishes an .mjs file.
@turf/meta][meta]No longer publishes an .mjs file.
@turf/tag][tag]Add MultiPolygon support. (PR https://github.com/Turfjs/turf/pull/1996 - Author bryceroney)
@turf/centroid Don't visit first point twice when calculating centroid
(PR https://github.com/Turfjs/turf/pull/1894 - Author @rowanwins)
@turf/transform-translate Better handling of negative distances
(PR https://github.com/Turfjs/turf/pull/1895 - Author @rowanwins)
@turf/union, @turf/difference, @turf/intersect Use polygon-clipping library to fix correctness issues
(PR https://github.com/Turfjs/turf/pull/1916 - Authors @mbullington, @ngottlieb)
@turf/buffer Change default number of steps to 8, and actually support the steps option
(PR https://github.com/Turfjs/turf/pull/1931 - Author stevenchanin)
@turf/buffer Fix projection issues that produce undersized buffers at non-equatorial latitudes
(PR https://github.com/Turfjs/turf/pull/1956 - Author dyakovlev)
@turf/helpers Add runtime checks to point() method, fixing an API break
(PR https://github.com/Turfjs/turf/pull/1964)
@turf/boolean-overlap Better performance for MultiPoint geometries
(PR https://github.com/Turfjs/turf/pull/1910 - Author @mfedderly)
@turf/helpers Add hectares to convertArea
(PR https://github.com/Turfjs/turf/pull/1943 - Author @DanielJDufour)
@turf/great-circle Update Typescript types to support MultiLineString input
(PR https://github.com/Turfjs/turf/pull/1928 - Author kronick)
@turf/square-grid Clarify inputs
(PR https://github.com/Turfjs/turf/pull/1885 - Author @raphael-leger)
@turf/greater-circle Clarify properties option example
(PR https://github.com/Turfjs/turf/pull/1888 - Author @chris-catignani)
@turf/line-to-polygon no longer modifies its input unless the mutate option is true
(PR https://github.com/Turfjs/turf/pull/1879 - Author @MortenBirk)
@turf/unkink-polygon remove Number.prototype.modulo override
(PR https://github.com/Turfjs/turf/pull/1978)
FAQs
turf nearest-neighbor-analysis module
The npm package @turf/nearest-neighbor-analysis receives a total of 157,118 weekly downloads. As such, @turf/nearest-neighbor-analysis popularity was classified as popular.
We found that @turf/nearest-neighbor-analysis demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 0 open source maintainers collaborating on the project.
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