let map = null;

function initializeMap(mapImgUrl) {
  map = L.map('map', { minZoom: 0, maxZoom: 4, crs: L.CRS.Simple });
  L.imageOverlay(mapImgUrl, [[-180, 180],[180, -180]]).addTo(map);
  map.setMaxBounds([[-180,180],[180,-180]]);
  map.setView([0,0], 2);
}