Cesiumjs Spatial Math

import { Cartesian3, Math as CesiumMath } from "cesium";

// From lon/lat degrees -- most common entry point
const pos = Cartesian3.fromDegrees(-105.0, 40.0);
const elevated = Cartesian3.fromDegrees(-105.0, 40.0, 1500.0); // with height

// Batch creation: [lon, lat, lon, lat, ...]
const ring = Cartesian3.fromDegreesArray([-105, 40, -100, 40, -100, 35]);

// With heights: [lon, lat, h, lon, lat, h, ...]
const wall = Cartesian3.fromDegreesArrayHeights([-105, 40, 500, -100, 40, 1000]);

// From raw ECEF or from radians
const raw = new Cartesian3(-1275096.0, -4797180.0, 4075270.0);
const fromRad = Cartesian3.fromRadians(-1.8326, 0.6981, 1500.0);

// Constants
Cartesian3.ZERO;   // (0,0,0)
Cartesian3.UNIT_X; // (1,0,0)
Cartesian3.UNIT_Y; // (0,1,0)
Cartesian3.UNIT_Z; // (0,0,1)

const a = new Cartesian3(1.0, 2.0, 3.0);
const b = new Cartesian3(4.0, 5.0, 6.0);
const r = new Cartesian3(); // reusable scratch

Cartesian3.add(a, b, r);                // a + b
Cartesian3.subtract(a, b, r);           // a - b
Cartesian3.multiplyByScalar(a, 2.0, r); // a * 2
Cartesian3.negate(a, r);                // -a
Cartesian3.cross(a, b, r);              // cross product
Cartesian3.normalize(a, r);             // unit vector
Cartesian3.lerp(a, b, 0.5, r);         // linear interpolation
Cartesian3.midpoint(a, b, r);           // midpoint

const dot = Cartesian3.dot(a, b);       // dot product
const len = Cartesian3.magnitude(a);    // ||a||
const dist = Cartesian3.distance(a, b); // Euclidean distance
const distSq = Cartesian3.distanceSquared(a, b); // faster for comparisons
const angle = Cartesian3.angleBetween(a, b);     // radians

import { Cartographic, Cartesian3, Math as CesiumMath } from "cesium";

const carto = Cartographic.fromDegrees(-105.0, 40.0, 1500.0);
const cartoRad = Cartographic.fromRadians(-1.8326, 0.6981, 1500.0);

// Cartesian3 <-> Cartographic
const position = Cartesian3.fromDegrees(-105.0, 40.0, 1500.0);
const geo = Cartographic.fromCartesian(position);
const lonDeg = CesiumMath.toDegrees(geo.longitude); // -105.0
const latDeg = CesiumMath.toDegrees(geo.latitude);  // 40.0
const backToCart = Cartographic.toCartesian(geo);

import { Math as CesiumMath } from "cesium";

// Degree/radian conversion
const rad = CesiumMath.toRadians(90.0);    // PI/2
const deg = CesiumMath.toDegrees(Math.PI); // 180

// Constants: PI, TWO_PI, PI_OVER_TWO, PI_OVER_FOUR, RADIANS_PER_DEGREE
// EPSILON1 (0.1) through EPSILON21 (1e-21)

const clamped = CesiumMath.clamp(value, 0.0, 1.0);
const interp = CesiumMath.lerp(0.0, 100.0, 0.5);          // 50
const norm = CesiumMath.negativePiToPi(angle);              // [-PI, PI]
const pos = CesiumMath.zeroToTwoPi(angle);                  // [0, 2*PI]
const safeLon = CesiumMath.convertLongitudeRange(angle);    // [-PI, PI)
const eq = CesiumMath.equalsEpsilon(a, b, CesiumMath.EPSILON7); // float compare

import { Ellipsoid, Cartesian3, Cartographic } from "cesium";

// Built-in ellipsoids
Ellipsoid.WGS84;       // Earth (default)
Ellipsoid.UNIT_SPHERE;  // radius 1
Ellipsoid.MOON;         // lunar sphere
Ellipsoid.MARS;         // Mars (v1.133+)

// Change default (affects Ellipsoid.default everywhere)
Ellipsoid.default = Ellipsoid.MOON;

// Conversions on a specific ellipsoid
const cart = Ellipsoid.WGS84.cartographicToCartesian(
  Cartographic.fromDegrees(-75.0, 40.0, 100.0),
);
const carto = Ellipsoid.WGS84.cartesianToCartographic(cart);

// Surface normal at a position
const normal = Ellipsoid.WGS84.geodeticSurfaceNormal(cart, new Cartesian3());

// Project point onto ellipsoid surface
const onSurface = Ellipsoid.WGS84.scaleToGeodeticSurface(cart, new Cartesian3());

import { Cartesian3, Transforms, Matrix4 } from "cesium";

const origin = Cartesian3.fromDegrees(-105.0, 40.0);
const enuMatrix = Transforms.eastNorthUpToFixedFrame(origin);
// Columns: [east, north, up, origin] in ECEF

import { Cartesian3, Transforms, HeadingPitchRoll, Math as CesiumMath } from "cesium";

const position = Cartesian3.fromDegrees(-105.0, 40.0, 0.0);
const hpr = new HeadingPitchRoll(
  CesiumMath.toRadians(90.0), // heading: 90 deg east
  0.0,                         // pitch: level
  0.0,                         // roll: none
);
const modelMatrix = Transforms.headingPitchRollToFixedFrame(position, hpr);

// Just the orientation quaternion (e.g., for Entity.orientation)
const orientation = Transforms.headingPitchRollQuaternion(position, hpr);

import { HeadingPitchRoll, Math as CesiumMath } from "cesium";
const hpr = new HeadingPitchRoll(CesiumMath.toRadians(45.0), CesiumMath.toRadians(-10.0), 0.0);
const hprDeg = HeadingPitchRoll.fromDegrees(45.0, -10.0, 0.0); // convenience

import { Transforms, Cartesian3 } from "cesium";
const origin = Cartesian3.fromDegrees(-105.0, 40.0);

Transforms.northEastDownToFixedFrame(origin);  // NED (aviation)
Transforms.northUpEastToFixedFrame(origin);     // NUE

// Custom frame from any combo of east|north|up|west|south|down
const customFn = Transforms.localFrameToFixedFrameGenerator("north", "west");
const matrix = customFn(origin);

// Recover heading/pitch/roll from an existing model matrix
const hpr = Transforms.fixedFrameToHeadingPitchRoll(modelMatrix);

import { Matrix4, Matrix3, Cartesian3, Quaternion } from "cesium";

// Factory methods
Matrix4.fromTranslation(new Cartesian3(10, 20, 30));
Matrix4.fromRotationTranslation(Matrix3.fromRotationZ(Math.PI / 4), new Cartesian3(100, 0, 0));
Matrix4.fromTranslationQuaternionRotationScale(
  new Cartesian3(0, 0, 0), Quaternion.IDENTITY, new Cartesian3(2, 2, 2),
);
Matrix4.fromUniformScale(5.0);

// Combine, transform, invert
const combined = Matrix4.multiply(matA, matB, new Matrix4());
const worldPt = Matrix4.multiplyByPoint(enuMatrix, new Cartesian3(100, 0, 0), new Cartesian3());
const inv = Matrix4.inverseTransformation(enuMatrix, new Matrix4()); // rigid-body only

// Decompose
Matrix4.getTranslation(enuMatrix, new Cartesian3());
Matrix4.getMatrix3(enuMatrix, new Matrix3());
Matrix4.getScale(enuMatrix, new Cartesian3());

import { Quaternion, Cartesian3, HeadingPitchRoll, Math as CesiumMath, Matrix3, Matrix4, Transforms } from "cesium";

Quaternion.IDENTITY; // (0, 0, 0, 1)
const q1 = Quaternion.fromAxisAngle(Cartesian3.UNIT_Z, CesiumMath.toRadians(45.0));
const q2 = Quaternion.fromHeadingPitchRoll(new HeadingPitchRoll(CesiumMath.toRadians(90), 0, 0));
const q3 = Quaternion.fromRotationMatrix(Matrix3.fromRotationZ(Math.PI / 2));
const mid = Quaternion.slerp(q1, q2, 0.5, new Quaternion());       // interpolate
const composed = Quaternion.multiply(q1, q2, new Quaternion());     // compose

import { Cartesian3, Quaternion, Matrix3, Matrix4, Transforms, Math as CesiumMath } from "cesium";

const origin = Cartesian3.fromDegrees(-115.17, 36.11, 3000.0);

// 1. Build local-to-ECEF frame at origin
const enuFrame = Transforms.eastNorthUpToFixedFrame(origin);

// 2. Build quaternion for 45-deg yaw about local up axis
const q = Quaternion.fromAxisAngle(Cartesian3.UNIT_Z, CesiumMath.toRadians(45.0));

// 3. Convert quaternion → Matrix3 → Matrix4 (zero translation in local frame)
const rot3 = Matrix3.fromQuaternion(q, new Matrix3());
const rotMatrix4 = Matrix4.fromRotationTranslation(rot3, Cartesian3.ZERO, new Matrix4());

// 4. Compose: ENU frame * local rotation = final model matrix
const modelMatrix = Matrix4.multiply(enuFrame, rotMatrix4, new Matrix4());

import { Cartographic, EllipsoidGeodesic, Cartesian3 } from "cesium";

// Surface distance (great-circle via Vincenty) -- correct for "distance between cities"
const geodesic = new EllipsoidGeodesic(
  Cartographic.fromDegrees(-73.985, 40.758),  // New York
  Cartographic.fromDegrees(-0.1276, 51.5074), // London
);
const surfaceDist = geodesic.surfaceDistance;              // ~5,837,000 m (~5,837 km)
const midCarto = geodesic.interpolateUsingFraction(0.5);  // midpoint on surface

// Chord (straight-line through ellipsoid interior) -- rarely what you want for geography
const chord = Cartesian3.distance(
  Cartesian3.fromDegrees(-73.985, 40.758),
  Cartesian3.fromDegrees(-0.1276, 51.5074),
); // shorter than surfaceDistance; do NOT use for "distance between cities"