Contents

// @import two-point-equidistant

function twoPointAzimuthal(d) {
  var cosd = Math.cos(d);

  function forward(λ, φ) {
    var coordinates = d3.geo.gnomonic.raw(λ, φ);
    coordinates[0] *= cosd;
    return coordinates;
  }

  forward.invert = function(x, y) {
    return d3.geo.gnomonic.raw.invert(x / cosd, y);
  };

  return forward;
}

function twoPointAzimuthalProjection() {
  var points = [[0, 0], [0, 0]],
      m = projectionMutator(twoPointAzimuthal),
      p = m(0),
      rotate = p.rotate;

  delete p.rotate;

  p.points = function(_) {
    if (!arguments.length) return points;
    points = _;

    var interpolate = d3.geo.interpolate(_[0], _[1]),
        origin = interpolate(.5),
        p = twoPointEquidistant_rotate(-origin[0] * radians, -origin[1] * radians, _[0][0] * radians, _[0][1] * radians),
        b = interpolate.distance * .5, // |[0, 0] - p|
        c = (p[0] < 0 ? -1 : +1) * p[1], // |[p[0], 0] - p|
        γ = asin(Math.sin(c) / Math.sin(b));

    rotate.call(p, [-origin[0], -origin[1], -γ * degrees]);

    return m(b);
  };

  return p;
}

(d3.geo.twoPointAzimuthal = twoPointAzimuthalProjection).raw = twoPointAzimuthal;

Version data entries

2 entries across 2 versions & 1 rubygems

Version	Path
d3js-plugins-rails-0.0.4	vendor/assets/javascripts/d3/plugins/geo/projection/two-point-azimuthal.js
d3js-plugins-rails-0.0.3	vendor/assets/javascripts/d3/plugins/geo/projection/two-point-azimuthal.js