绘制点,使它们在坐标相同时不会重叠

首先将坐标分组。你的长,纬度->x、 直到最后一步才需要y转换。一种方法是创建一个哈希映射,在其中存储每个long/lat位置和每个位置的计数。

然后将每个长纬度位置转换为x,y坐标,并使用计数来决定如何渲染以x,y位置为中心但大小取决于点数的点。

渲染正方形的工作算法是:

var count = 30; // example
result = [];

var width = count/Math.sqrt(count);
width = Math.floor(width);
height = Math.floor(count/width);
var remain = count % width;

var i,j;

for(i = 0; i < width; i++)
  for(j = 0; j < height; j++)
    result.push([x-Math.floor(width/2)+i, y-Math.floor(height/2)+j]; 
for(i = 0; i < remain; i++)
  result.push([x-Math.floor(width/2)+i, y-Math.floor(height/2)+j];

输入是点的计数,x,y中心坐标,输出是要渲染的点的数组。

最后一行是剩余的点,例如一个15点的正方形:

OOOO
OOOO
OOOO
OOO

Ernelli的解决方案在第二个for循环中有一个错误:

for(j = 0; i < height; i++)

for(j = 0; j < height; j++)

var countArray = new Array();

// Go through every point and group same co-ordinates together 
for (var i = pointArray.length-1; i > -1; i--) {
    if(pointArray[i] != undefined) 
    { 
        var found = 0;

        // Check if this point is already in array
        for (var j = countArray.length-1; j > -1; j--)
        {
            if(countArray[j] != undefined)
            {
                if((pointArray[i].getBBox().x == countArray[j]["x"]) && (pointArray[i].getBBox().y == countArray[j]["y"]))
                {
                    countArray[j]["points"].push(pointArray[i]);
                    found = 1;
                }
            } 
        }

        // The point is not in the array, so add it
        if(found != 1) 
        {
            var index = countArray.length;
            countArray[index] = new Array();
            countArray[index]["x"] = pointArray[i].getBBox().x;
            countArray[index]["y"] = pointArray[i].getBBox().y;
            countArray[index]["points"] = new Array();
            countArray[index]["points"].push(pointArray[i]);
        }

    }
}

// For each co-ordinate
for (var j = countArray.length-1; j > -1; j--)
{
    if(countArray[j] != undefined)
    {   
        // If there is more than one point
        if(countArray[j]["points"].length > 1) {

            // Calculate the square points
            var count = countArray[j]["points"].length;
            var x = countArray[j]["x"];
            var y = countArray[j]["x"];
            result = [];

            var width = count/Math.sqrt(count);
            width = Math.floor(width);
            height = Math.floor(count/width);
            var remain = count % width;


            var i2,j2, xx, yy;
            var space = 8;
            for(i2 = 0; i2 < width*space; i2+=space)
            {
              for(j2 = 0; j2 < height*space; j2+=space)
                {
                result.push([(Math.floor(width/2)+i2), (Math.floor(height/2)+j2)]); 
                }   
            }
            for(i2 = 0; i2 < remain*space; i2+=space)
            {
              result.push([(Math.floor(width/2)+i2), (Math.floor(height/2)+j2)]);
            }

            // Go through each point and then translate it to it's new position
            for (var jj = countArray[j]["points"].length-1; jj > -1; jj--)
            {
                if(countArray[j]["points"][jj] != undefined)
                {
                    if(result[jj] != undefined)
                    {   
                        countArray[j]["points"][jj].translate(result[jj][0]-((width*8)/2), result[jj][1]-((height*8)/2))
                    }
                }
            }
        } // End if count more than 1
    } // End if undefined
}

raphael.js 函数(如getBBox和translate)