一、根據resolution計算scale:
var scale2=0.0254/96/0.35156249999999994/Math.PI/2/6378137*360;
解釋:0.0254代表每英寸0.0254米
96代表:dpi 每英寸96個像素點
resolution: 0.35156249999999994
6378137:地球半徑
二、根據scale計算resolution
var resolution2=147914677*(0.0254/96/Math.PI/2/6378137*360);
解釋:147914677代表scales
測試代碼:
<html>
<body>
<script type="text/javascript">
//第七級 resolution
var resolution=0.00008596045914639882;
//座標原點:
var x0=-180;
var y0=90;
//切圖範圍,示例左下角
var minx=88.390660499999981;
var miny=42.729192000000005;
var tilex=(minx-x0)/resolution/256;
var tiley=(miny-y0)/resolution/256;
document.write(tilex+ "<br />");
document.write(tiley+ "<br />");
//1.scale計算resolution,網上算法
var scale=147914677.7272828;
document.write(scale+ "<br />");
var res=scale*0.02540005080010160020/96/111194.872221777;
document.write(scale+ "<br />");
document.write(res+ "<br />");
//2.resolution計算scale,精確算法
var scale2=0.0254/96/0.35156249999999994/Math.PI/2/6378137*360;
document.write((1/scale2)+ "<br />");
var scale2=1/(0.0254/96/0.35156249999999994/Math.PI/2/6378137*360);
var resolution2=147914677*(0.0254/76.2/Math.PI/2/6378137*360);
document.write(resolution2+"<br />");
document.write(Math.PI*2*6378137/360);
</script>
</body>
</html>