Sha256: 6f7774c11c04a9bf9e7bfd01011b1e587764f457e529c54bfd9c489e39062df5
Contents?: true
Size: 1.54 KB
Versions: 6
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Stored size: 1.54 KB
Contents
/**
* 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;
});
Version data entries
6 entries across 3 versions & 1 rubygems