@turf/isolines
Advanced tools
@turf/isolines is a module within the Turf.js library that allows you to generate isolines (contour lines) from a grid of points with z-values. This is useful for visualizing elevation, temperature, or other continuous data over a geographic area.
Generate Isolines
This feature allows you to generate isolines from a grid of points with z-values. The code sample demonstrates creating a grid of points, assigning random z-values, and generating isolines based on specified breaks.
const turf = require('@turf/turf');
// Create a grid of points with z-values
const points = turf.pointGrid([-95, 30, -85, 40], 100, { units: 'miles' });
points.features.forEach((point, i) => {
point.properties.z = Math.random() * 10;
});
// Generate isolines
const breaks = [0, 2, 4, 6, 8, 10];
const isolines = turf.isolines(points, breaks, { zProperty: 'z' });
console.log(JSON.stringify(isolines));d3-contour is a module in the D3.js library that provides tools for generating contour plots. It is similar to @turf/isolines in that it can generate contour lines from a set of data points. However, d3-contour is more focused on data visualization and is part of the broader D3.js ecosystem, which is widely used for creating complex and interactive visualizations.
marching-squares is a JavaScript library for generating contour lines using the Marching Squares algorithm. It is similar to @turf/isolines in that it can generate contour lines from a grid of data points. However, marching-squares is a more specialized library focused solely on the contour generation algorithm, whereas @turf/isolines is part of the larger Turf.js library for geospatial analysis.
Takes a grid FeatureCollection of Point features with z-values and an array of value breaks and generates isolines.
Parameters
pointGrid FeatureCollection<Point> input pointsbreaks Array<number> values of zProperty where to draw isolinesoptions Object Optional parameters (optional, default {})
options.zProperty string the property name in points from which z-values will be pulled (optional, default 'elevation')options.commonProperties Object GeoJSON properties passed to ALL isolines (optional, default {})options.breaksProperties Array<Object> GeoJSON properties passed, in order, to the correspondent isoline;
the breaks array will define the order in which the isolines are created (optional, default [])Examples
// create a grid of points with random z-values in their properties
var extent = [0, 30, 20, 50];
var cellWidth = 100;
var pointGrid = turf.pointGrid(extent, cellWidth, {units: 'miles'});
for (var i = 0; i < pointGrid.features.length; i++) {
pointGrid.features[i].properties.temperature = Math.random() * 10;
}
var breaks = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
var lines = turf.isolines(pointGrid, breaks, {zProperty: 'temperature'});
//addToMap
var addToMap = [lines];
Returns FeatureCollection<MultiLineString> a FeatureCollection of MultiLineString features representing isolines
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/isolines
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 isolines module
The npm package @turf/isolines receives a total of 376,401 weekly downloads. As such, @turf/isolines popularity was classified as popular.
We found that @turf/isolines 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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