refactor(geo): define shared distance contract

src/cockpitCloudEffects.js

@@ -1,5 +1,6 @@
 import { applicationServices } from './services/application.js';
 import * as Cesium from 'cesium';
+import { greatCircleMeters } from './geoDistance.js';
 import {
   deriveWeatherEffectProfile,
   weatherAltitudeFactors,
@@ -127,23 +128,9 @@ function compileShader(gl, type, source) {
 }
 
 function greatCircleM(a, b) {
-  if (
-    ![a?.latitude, a?.longitude, b?.latitude, b?.longitude].every(
-      Number.isFinite,
-    )
-  )
-    return Infinity;
-  const latitudeA = Cesium.Math.toRadians(a.latitude);
-  const latitudeB = Cesium.Math.toRadians(b.latitude);
-  const latitudeDelta = Cesium.Math.toRadians(b.latitude - a.latitude);
-  const longitudeDelta = Cesium.Math.toRadians(b.longitude - a.longitude);
-  const haversine =
-    Math.sin(latitudeDelta / 2) ** 2 +
-    Math.cos(latitudeA) *
-      Math.cos(latitudeB) *
-      Math.sin(longitudeDelta / 2) ** 2;
-  return (
-    6371000 * 2 * Math.atan2(Math.sqrt(haversine), Math.sqrt(1 - haversine))
+  return greatCircleMeters(
+    { lat: a?.latitude, lon: a?.longitude },
+    { lat: b?.latitude, lon: b?.longitude },
   );
 }