text: /**
   * echarts地图投射算法
   *
   * @desc echarts基于Canvas，纯Javascript图表库，提供直观，生动，可交互，可个性化定制的数据统计图表。
   * @author Kener (@Kener-林峰, kener.linfeng@gmail.com)
   *
   */
  define(function() {
      // 墨卡托投射
      function _mercator() {
          var radians = Math.PI / 180;
          var scale = 500;
          var translate = [480, 250];
  
          function mercator(coordinates) {
              var x = coordinates[0] / 360;
              var y = -(Math.log(Math.tan(
                          Math.PI / 4 + coordinates[1] * radians / 2
                      )) / radians) / 360;
              return [
                  scale * x + translate[0],
                  scale * Math.max(-0.5, Math.min(0.5, y)) + translate[1]
              ];
          }
  
  
          mercator.invert = function (coordinates) {
              var x = (coordinates[0] - translate[0]) / scale;
              var y = (coordinates[1] - translate[1]) / scale;
              return [
                  360 * x,
                  2 * Math.atan(Math.exp(-360 * y * radians)) / radians - 90
              ];
          };
  
          mercator.scale = function (x) {
              if (!arguments.length) {
                  return scale;
              }
              scale = +x;
              return mercator;
          };
  
          mercator.translate = function (x) {
              if (!arguments.length) {
                  return translate;
              }
              translate = [+x[0], +x[1]];
              return mercator;
          };
  
          return mercator;
      }
  
      return _mercator;
  }); 