code: function (p, buffer) {
          var v = buffer / this.ky;
          var h = buffer / this.kx;
          return [
              p[0] - h,
              p[1] - v,
              p[0] + h,
              p[1] + v
          ];
      }
docs: Given a point, returns a bounding box object ([w, s, e, n]) created from the given point buffered by a given distance.
  
  @param {Array<number>} p point [longitude, latitude]
  @param {number} buffer
  @returns {Array<number>} box object ([w, s, e, n])
  @example
  var bbox = ruler.bufferPoint([30.5, 50.5], 0.01);
  //=bbox