polarmap/examples/Leaflet.PolarMap/layers-switcher/demo.js

Leaflet library for polar map projection switching

var map;

// Create object to define tile provider settings and transformations. Supports
// all Leaflet TileLayer options.
var projectedTiles = {
  "EPSG:3571 Bering Sea": L.PolarMap.layer3571,
  "EPSG:3572 Alaska"    : L.PolarMap.layer3572,
  "EPSG:3573 Canada"    : L.PolarMap.layer3573,
  "EPSG:3574 Atlantic"  : L.PolarMap.layer3574,
  "EPSG:3575 Europe"    : L.PolarMap.layer3575,
  "EPSG:3576 Russia"    : L.PolarMap.layer3576
};

// Set up next/prev linked list
$.each(projectedTiles, function (layerName, layer) {
  var keys = Object.keys(projectedTiles);
  var index = keys.indexOf(layerName);
  var prev = (index === 0) ? keys.length - 1 : index - 1;
  var next = (index === keys.length - 1) ? 0 : index + 1;

  layer.prev = projectedTiles[keys[prev]];
  layer.next = projectedTiles[keys[next]];
});

// Initialization
$(document).ready(function() {
  Autosize.enable();

  // Load PolarMap
  var defaultLayer = projectedTiles["EPSG:3571 Bering Sea"];
  map = L.PolarMap.map('xmap', {
    baseLayer: defaultLayer,
    center: defaultLayer.options.center,
    zoom: defaultLayer.options.zoom
  });

  // Add a Leaflet layer group. Assumed to be EPSG:3857.
  L.layerGroup([
    L.marker([51.080126, -114.13380900]).bindPopup("University of Calgary"),
    L.marker([90, 100]).bindPopup("North Pole")
  ]).addTo(map);

  var layersControl = L.control.layers(projectedTiles, null);
  layersControl.addTo(map);

  // Wire up rotation controls
  var getBaseLayer = function() {
    var foundLayer = null;
    $.each(projectedTiles, function (layerName, layer) {
      if (map.hasLayer(layer)) {
        foundLayer = layer;
      }
    });
    return foundLayer;
  };

  var rotationControls = L.PolarMap.Control.rotation({
    onRotateCW: function() {
      map.loadTileProjection(getBaseLayer().next);
    },

    onRotateCCW: function() {
      map.loadTileProjection(getBaseLayer().prev);
    }
  });
  rotationControls.addTo(map);
});