ptx2geo.php

<?php
$cities = [
    'Taipei',
    'NewTaipei',
    'Taoyuan',
    'Taichung',
    'Tainan',
    'Kaoshiung',
    'KinmenCountry',
    'TaipeiCloud',
];
$parameters = [
    'select',
    'filter',
    'orderby',
    'top',
    'skip',
];

$apiUrlPrefix = 'http://ptx.transportdata.tw/MOTC/v2/Bus/Shape/City/';
$city = $_GET['city'] ?? '';
if (!in_array($city, $cities))
    $city = $cities[0];

$apiUrl = $apiUrlPrefix . $city. '?$format=json';
foreach ($parameters as $parameter)
    if (isset($_GET[$parameter]))
        $apiUrl .= '&$' . $parameter . '=' . urlencode($_GET[$parameter]);

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $apiUrl);
curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/4.0 (RM Studio)');

ob_start();
curl_exec($ch);
$raw = ob_get_contents();
ob_end_clean();

curl_close($ch);

$data = json_decode($raw, true);
$geojson = [
    'type' => 'FeatureCollection',
    'features' => [],
];

foreach ($data as $route) {
    $feature = [
        'type' => 'Feature',
        'properties' => [],
        'geometry' => [
            'type' => 'LineString',
            'coordinates' => [],
        ],
    ];

    foreach ($route as $key => $value) {
        if ($key == 'Geometry') {
            $coor = explode(', ', substr($value, 12, -1));
            foreach ($coor as &$c) {
                $c = explode(' ', $c);
                $c[0] = (double)$c[0];
                $c[1] = (double)$c[1];
            }
            $feature['geometry']['coordinates'] = $coor;
            continue;
        }
        $feature['properties'][$key] = $value;
    }

    $geojson['features'][] = $feature;
}

echo(json_encode($geojson));