code: function(lineP1, lineP2, point, radius) {
      var distance =
        Math.abs(
          ((lineP2.y - lineP1.y)*point.x) - ((lineP2.x - lineP1.x)*point.y) + (lineP2.x*lineP1.y) - (lineP2.y*lineP1.x)
        ) /
        Math.sqrt(
          Math.pow(lineP2.y - lineP1.y, 2) + Math.pow(lineP2.x - lineP1.x, 2)
        );
      return distance <= radius;
    }
docs: http://math.stackexchange.com/questions/275529/check-if-line-intersects-with-circles-perimeter https://en.wikipedia.org/wiki/Distance_from_a_point_to_a_line [lng x, lat, y]