turf-tin

tin

Takes a set of points and the name of a z-value property and creates a Triangulated Irregular Network, or a TIN for short, returned as a collection of Polygons. These are often used for developing elevation contour maps or stepped heat visualizations.

This triangulates the points, as well as adds properties called a, b, and c representing the value of the given propertyName at each of the points that represent the corners of the triangle.

Parameters

• points FeatureCollection<Point> input points
• z [String] name of the property from which to pull z values This is optional: if not given, then there will be no extra data added to the derived triangles.

Examples

// generate some random point data
var points = turf.random('points', 30, {
  bbox: [50, 30, 70, 50]
});
//=points
// add a random property to each point between 0 and 9
for (var i = 0; i < points.features.length; i++) {
  points.features[i].properties.z = ~~(Math.random() * 9);
}
var tin = turf.tin(points, 'z')
for (var i = 0; i < tin.features.length; i++) {
  var properties  = tin.features[i].properties;
  // roughly turn the properties of each
  // triangle into a fill color
  // so we can visualize the result
  properties.fill = '#' + properties.a +
    properties.b + properties.c;
}
//=tin

Returns FeatureCollection<Polygon> TIN output

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-tin

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

$ npm install turf