Displaying pins around a point in google maps

Is there a way to translate into ja开发者_StackOverflow中文版vascript a piece of code that will allow me to show map pins around a point taking in consideration a radius ?

var data=[
  {long:3,lat:2},
  {long:5,lat:2},
  {long:2,lat:3}
];

aCoord={long:1,lat:2};

for(var i=0;i<data.length;i++){
  if (data[i] is 30 kms far from aCoord)
    myMap.addPin(data[i]);
}

myMap.autozoom();

Thank you,

Regards

I came up with this example so you have an idea on how to calculate the points. You'll need to figure out how to do any necessary conversions for lat/lon.

/**
* Returns coordinates for N points around a circle with a given radius from
* the center.
*
* center: array [x, y]
* radius: int
* num_points: int
*/
function get_points_on_circle(center, radius, num_points) {
    if (!num_points) num_points = 10;

    var interval = Math.PI * 2 / num_points;
        points = [];

    i = -1;
    while (++i < num_points) {
        var theta = interval * i,
            point = [Math.cos(theta) * radius + center[0], Math.sin(theta) * radius + center[1]];
        points.push(point);
    }

    return points;
}


// Sample usage
var center = [250, 250],
    radius = 100,
    num_points = 10;

var points = get_points_on_circle(center, radius, num_points);

Test it out (uses Raphael for plotting)

If you are interested in learning a little about the logic:

• A radian is a unit of measure for angles. There are a total of 2*PI radians in a circle. Using that fact, you can calculate the angle interval of any number of points on a circle by performing 2*PI/num_points.

• When you know the angle interval, you can calculate the angle (theta) of a point on a circle. Once you have theta (the angle), you have polar coordinates (radius,angle). For that to be of any use to us in this problem, you need to convert the polar coordinates into Cartesian coordinates (x,y). You can do that by using the following formulas:
  x = cos(theta) * radius
  y = sin(theta) * radius

That's pretty much it in a nutshell.