function initializeChangesets(map) {
  var changesets = [], rects = {};

  var group = L.featureGroup().addTo(map);

  $("[data-changeset]").each(function () {
    var changeset = $(this).data('changeset');
    if (changeset.bbox) {
      changeset.bounds = L.latLngBounds([changeset.bbox.minlat, changeset.bbox.minlon],
                                        [changeset.bbox.maxlat, changeset.bbox.maxlon]);
      changesets.push(changeset);
    }
  });

  changesets.sort(function (a, b) {
    return b.bounds.getSize() - a.bounds.getSize();
  });

  for (var i = 0; i < changesets.length; ++i) {
    var changeset = changesets[i],
        rect = L.rectangle(changeset.bounds,
                           {weight: 2, color: "#ee9900", fillColor: "#ffff55", fillOpacity: 0});
    rect.id = changeset.id;
    rects[changeset.id] = rect;
    rect.addTo(group);
  }

  function highlightChangeset(id) {
    rects[id].setStyle({fillOpacity: 0.5});
    $("#changeset_" + id).addClass("selected");
  }

  function unHighlightChangeset(id) {
    rects[id].setStyle({fillOpacity: 0});
    $("#changeset_" + id).removeClass("selected");
  }

  group.on({
    mouseover: function (e) {
      highlightChangeset(e.layer.id);
    },
    mouseout: function (e) {
      unHighlightChangeset(e.layer.id);
    }
  });

  $("[data-changeset]").on({
    mouseover: function () {
      highlightChangeset($(this).data("changeset").id);
    },
    mouseout: function () {
      unHighlightChangeset($(this).data("changeset").id);
    }
  });
}