Takes a triangular plane as a Polygon and a Point within that triangle and returns the z-value at that point. The Polygon should have properties a, b, and c that define the values at its three corners. Alternatively, the z-values of each triangle point can be provided by their respective 3rd coordinate if their values are not provided as properties.

• point Coord the Point for which a z-value will be calculated
• triangle Feature<Polygon> a Polygon feature with three vertices

var point = turf.point([-75.3221, 39.529]);
// "a", "b", and "c" values represent the values of the coordinates in order.
var triangle = turf.polygon([[
  [-75.1221, 39.57],
  [-75.58, 39.18],
  [-75.97, 39.86],
  [-75.1221, 39.57]
]], {
  "a": 11,
  "b": 122,
  "c": 44
});

var zValue = turf.planepoint(point, triangle);
point.properties.zValue = zValue;

//addToMap
var addToMap = [triangle, point];

Returns number the z-value for interpolatedPoint

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/planepoint

Or install the all-encompassing @turf/turf module that includes all modules as functions:

$ npm install @turf/turf