Suppose I Draw a polygan using leaflet like in the follow demo: http://leaflet.github.io/Leaflet.draw/
My question is how I can determine if a given point reside inside the polygon or not.
Use the Ray Casting algorithm for checking if a point (marker) lies inside of a polygon:
function isMarkerInsidePolygon(marker, poly) {
var polyPoints = poly.getLatLngs();
var x = marker.getLatLng().lat, y = marker.getLatLng().lng;
var inside = false;
for (var i = 0, j = polyPoints.length - 1; i < polyPoints.length; j = i++) {
var xi = polyPoints[i].lat, yi = polyPoints[i].lng;
var xj = polyPoints[j].lat, yj = polyPoints[j].lng;
var intersect = ((yi > y) != (yj > y))
&& (x < (xj - xi) * (y - yi) / (yj - yi) + xi);
if (intersect) inside = !inside;
}
return inside;
};
See jsfiddle for example.
Original source for the code: https://github.com/substack/point-in-polygon/blob/master/index.js
See also 2014's similar answer, https://stackoverflow.com/a/41138512/287948