# Verify if XY is inside polygon

Question asked by jay.kapalczynski on Feb 6, 2017
Latest reply on Feb 9, 2017 by rastrauch

Is there a way via JS or Python to simply pass an XY to a function and determine if inside or outside a polygon (from a map Service)

I need to do this for Decimal Degrees, DMS, UTM etc.

I can do it like below BUT I would have to list out EVERY node and trying to do this for a complete state

``function inside(point, vs) {    var x = point, y = point;    var inside = false;    for (var i = 0, j = vs.length - 1; i < vs.length; j = i++) {        var xi = vs[i], yi = vs[i];        var xj = vs[j], yj = vs[j];        var intersect = ((yi > y) != (yj > y))            && (x < (xj - xi) * (y - yi) / (yj - yi) + xi);        if (intersect) inside = !inside;    }    return inside;};var polygon = [[4040958.21,261090.239],[4399737.773,261090.239],  [4399737.773,1004118.285],[4040958.21,1004118.285]]                                                 <!--// The below are two examples.  One of them is inside the other is outside to bounding box// inside -->test = inside([ 4147263, 646445.066 ], polygon); // true<!-- // outside --><!--test = inside([ 4537048, 694061 ], polygon); // false -->alert(test);``