terriajs/test/Map/EarthGravityModel1996Spec.js

Geospatial data visualization platform.

"use strict";

import Cartographic from "terriajs-cesium/Source/Core/Cartographic";
import EarthGravityModel1996 from "../../lib/Map/Vector/EarthGravityModel1996";
import gravityModel from "../../wwwroot/data/WW15MGH.DAC";

var describeIfSupported = EarthGravityModel1996.isSupported()
  ? describe
  : xdescribe;

describeIfSupported("EarthGravityModel1996", function () {
  var egm96;

  beforeAll(function () {
    egm96 = new EarthGravityModel1996(gravityModel);
  });

  // NGA calculator is here: http://earth-info.nga.mil/GandG/wgs84/gravitymod/egm96/intpt.html

  it("produces a single result consistent with NGA calculator", async function () {
    const height = await egm96.getHeight(0.0, 0.0);
    expect(height).toBe(17.16);
  });

  it("produces multiple results consistent with NGA calculator", async function () {
    var testData = [
      // longitude, latitude, expected height
      0.0, 89.74, 13.92, 180.0, 89.74, 13.49, -180.0, 89.74, 13.49, 0.0, -89.74,
      -29.55, 180.0, -89.74, -30.11, -180.0, -89.74, -30.11, 0.15, 0.0, 17.12,
      -0.15, 0.0, 17.17
    ];

    var cartographics = [];
    var i;

    for (i = 0; i < testData.length; i += 3) {
      cartographics.push(
        Cartographic.fromDegrees(testData[i], testData[i + 1], 0.0)
      );
    }

    await egm96.getHeights(cartographics);
    for (let i = 0; i < cartographics.length; ++i) {
      expect(
        Math.abs(cartographics[i].height - testData[i * 3 + 2])
      ).toBeLessThan(0.01);
    }
  });

  it("works at the north pole", async function () {
    const height = await egm96.getHeight(0.0, Math.PI);
    expect(height).toBe(13.61);
  });

  it("works at the south pole", async function () {
    const height = await egm96.getHeight(0.0, -Math.PI);
    expect(height).toBe(-29.53);
  });
});