How to Capture The Inside pushpins in polygon on virtual earth

How to Capture The Inside pushpins in polygon on virtual earth

• Marcio Sete

  Okay is this what your trying to do
  
  You have a polygon on the map, then you calculate the area of the polygon, and then you want to figure out which pushpins lie in that area
  
  If thats the case, here are some general steps I would recommend:
  
  1) Store all your pushpin ID's in a hidden list on the page
  
  2) Find the region of the polygon
  
  3) Now you can iterate through all your pushpin ID's, and see if any of them have a lat/long that fits in that area
  
  

• Ashok Ojha

  what about learning how to write questions that other people do understand

  
  
  

• hazz

  assuming that you are trying to do what derek is assuming, here's a little code snippet i found on the web and use to determine whether or not a point is within a polygon. i have included the original author's info at the top to credit him.

  /**
  * Determines if the given point is within the given n-sided polygon.
  *
  * @param polygon A space-delimited list of coordinates. (Required)
  * @param point A comma-delimited coordinate. (Required)
  * @return Returns a boolean.
  * @author Joshua L. Olson (joshua@waetech.com)
  * @version 1, December 7, 2004
  */
  function PointInPolygon(polygon, point) {
  var polygon_arr = ListToArray(polygon, " ");
  var polygon_arr_length = 0;
  
  var intersections = 0;
  
  var test_point_x = Val(ListFirst(point, ","));
  var test_point_y = Val(ListLast(point, ","));
  
  var i = "1";
  var dx = "0";
  var dy = "0";
  var cx = "0";
  
  var point_1 = "";
  var point_2 = "";
  var point_1_x = "";
  var point_1_y = "";
  var point_2_x = "";
  var point_2_y = "";
  var cross_y = "";
  
  polygon_arr_length = ArrayLen(polygon_arr);
  
  // Terminate early if this is not a complete polygon.
  if (polygon_arr_length LT "3") return false;
  
  // Append the first element to the end of the array so that we complete the
  // polygon, which is a prerequisite for this to work.
  ArrayAppend(polygon_arr, polygon_arr[1]);
  
  for (i = "1"; i LTE polygon_arr_length; i = i + "1") {
  // get the endpoints for the segment
  point_1 = polygon_arr;
  point_2 = polygon_arr[i + "1"];
  
  point_1_x = Val(ListFirst(point_1, ","));
  point_1_y = Val(ListLast(point_1, ","));
  
  point_2_x = Val(ListFirst(point_2, ","));
  point_2_y = Val(ListLast(point_2, ","));
  
  // Determine if segment crosses vector starting at point and extending right
  
  // Check that the line segment crosses the horizontal line extended left and
  // right from the given point. We consider end-points on the horizontal line to
  // be above the horizontal line.
  
  cross_y = ((point_1_y LT test_point_y) AND (point_2_y GTE
  test_point_y)) OR
  ((point_2_y LT test_point_y) AND (point_1_y GTE test_point_y));
  
  if (cross_y) {
  // The segment crosses the horizontal plane. Now determine if it's to the right
  // or left of the given point.
  
  dx = point_2_x - point_1_x;
  dy = point_2_y - point_1_y;
  
  // cx is the point at which the segment crosses the horizontal plane of the
  // given point. This is a basic geometric calculation.
  cx = point_1_x + (dx * (test_point_y - point_1_y) / dy);
  
  // If the crossing point is to the right of the given point, count it
  if (cx GT test_point_x)
  intersections = (intersections + 1) MOD 2;
  }
  
  }
  // An odd number of intersections indicates that the point is within the polygon
  
  return intersections IS 1;
  }
  

  
  

• bola shokry

  Hi,

  I draw a polygon on map and calculate the area of the polygon.

  
  
  
• How to Capture The Inside pushpins in polygon on virtual earth