old_contents: [
      {
         name: 'water_ocean',
         data: function (json) { return json['water']; }
      },
      {
          name: 'land_usages',
          data: function (json) {
            return {
                type: 'FeatureCollection',
                features: ((json['landuse']||{}).features||[]).filter(function (feature) {
                    feature.properties.kind = feature.properties.class;
                    return feature;
                })
            };
          }
      },
      {
         name: 'water_areas',
         data: function (json) { return json['waterway']; }
      },
      {
          name: 'roads',
          data: function (json) {
              return {
                  type: 'FeatureCollection',
                  features: (((json['road']||{}).features)||[]).concat(((json['bridge']||{}).features)||[]).filter(function (feature) {
                      if (['motorway', 'motorway_link'].indexOf(feature.properties.class) > 0) {
                          feature.properties.kind = 'highway';
                      }
                      else if (feature.properties.class == 'main') {
                          feature.properties.kind = 'major_road';
                      }
                      else if (['street', 'street_limited'].indexOf(feature.properties.class) > 0) {
                          feature.properties.kind = 'minor_road';
                      }
                      else {
                          feature.properties.kind = feature.properties.type;
                      }
                      return feature;
                  })
              };
          }
      },
      {
          name: 'buildings',
          data: function (json) { return json['building']; }
      }
  ]
  
new_contents: [
      {
         name: 'water_ocean',
         data: function (json) { return json['water']; }
      },
      {
          name: 'landuse',
          data: function (json) {
            return {
                type: 'FeatureCollection',
                features: ((json['landuse']||{}).features||[]).filter(function (feature) {
                    feature.properties.kind = feature.properties.class;
                    return feature;
                })
            };
          }
      },
      {
         name: 'water_areas',
         data: function (json) { return json['waterway']; }
      },
      {
          name: 'roads',
          data: function (json) {
              return {
                  type: 'FeatureCollection',
                  features: (((json['road']||{}).features)||[]).concat(((json['bridge']||{}).features)||[]).filter(function (feature) {
                      if (['motorway', 'motorway_link'].indexOf(feature.properties.class) > 0) {
                          feature.properties.kind = 'highway';
                      }
                      else if (feature.properties.class == 'main') {
                          feature.properties.kind = 'major_road';
                      }
                      else if (['street', 'street_limited'].indexOf(feature.properties.class) > 0) {
                          feature.properties.kind = 'minor_road';
                      }
                      else {
                          feature.properties.kind = feature.properties.type;
                      }
                      return feature;
                  })
              };
          }
      },
      {
          name: 'buildings',
          data: function (json) { return json['building']; }
      },
      {
          name: 'pois',
          data: function (json) {
            return {
                type: 'FeatureCollection',
                features: ((json['poi_labels']||{}).features||[]).filter(function (feature) {
                    feature.properties.kind = feature.properties.type;
                    return feature;
                })
            };
          }
      }
  ]
  
subject: fix layer name references to use new names