refactor(monorepo): move superset-ui to superset(stage 2) (#17552)

superset-frontend/plugins/legacy-plugin-chart-map-box/src/utils/geo.js

@@ -0,0 +1,33 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+import roundDecimal from './roundDecimal';
+
+export const EARTH_CIRCUMFERENCE_KM = 40075.16;
+export const MILES_PER_KM = 1.60934;
+
+export function kmToPixels(kilometers, latitude, zoomLevel) {
+  // Algorithm from: http://wiki.openstreetmap.org/wiki/Zoom_levels
+  const latitudeRad = latitude * (Math.PI / 180);
+  // Seems like the zoomLevel is off by one
+  const kmPerPixel =
+    (EARTH_CIRCUMFERENCE_KM * Math.cos(latitudeRad)) / 2 ** (zoomLevel + 9);
+
+  return roundDecimal(kilometers / kmPerPixel, 2);
+}