geojson and polyline intersection.html

<!DOCTYPE html>
<html>
<head>
    <title>Polyline Passes Through GeoJSON Check</title>
</head>
<body>

<h2>Polyline Passes Through GeoJSON Check</h2>

<div>
    <label for="geojson">Enter GeoJSON:</label><br>
    <textarea id="geojson" rows="5" cols="50"></textarea>
</div>

<div>
    <label for="polyline">Enter Polyline (Comma-separated lat,lng pairs):</label><br>
    <input type="text" id="polyline" style="width: 100%;">
</div>

<button onclick="checkPolyline()">Check</button>

<p id="result"></p>

<script>
    function checkPolyline() {
        var geojsonInput = document.getElementById("geojson").value;
        var polylineInput = document.getElementById("polyline").value;

        var geojson = JSON.parse(geojsonInput);
        var polylinePoints = polylineInput.split(',').map(function (pair) {
            var latLng = pair.split(',');
            return [parseFloat(latLng[0]), parseFloat(latLng[1])];
        });

        var pointInsideGeoJSON = false;
        if (geojson.type === 'Feature' && geojson.geometry.type === 'Polygon') {
            var polygonCoordinates = geojson.geometry.coordinates[0];
            pointInsideGeoJSON = isPointInsidePolygon(polylinePoints, polygonCoordinates);
        }

        var resultElement = document.getElementById("result");
        if (pointInsideGeoJSON) {
            resultElement.innerHTML = "The polyline passes through the given GeoJSON location.";
        } else {
            resultElement.innerHTML = "The polyline does not pass through the given GeoJSON location.";
        }
    }

    function isPointInsidePolygon(point, polygon) {
        var x = point[0], y = point[1];
        var isInside = false;
        for (var i = 0, j = polygon.length - 1; i < polygon.length; j = i++) {
            var xi = polygon[i][0], yi = polygon[i][1];
            var xj = polygon[j][0], yj = polygon[j][1];

            var intersect = ((yi > y) !== (yj > y)) &&
                (x < (xj - xi) * (y - yi) / (yj - yi) + xi);
            if (intersect) isInside = !isInside;
        }
        return isInside;
    }
</script>

</body>
</html>