How to extract route GPX from a Google Maps route?17.03.25

The solution lies in the "data" param in the expanded url for the google maps route link.

Lets take this URL for example - https://goo.gl/maps/zrcP5gL1cd2AHGoq8

This expands to https://www.google.com/maps/dir/Eiffel+Tower,+Paris,+France/Palais+Garnier,+Pl.+de+l'Op%C3%A9ra,+75009+Paris,+France/@48.8606129,2.2961092,14z/am=t/data=!4m29!4m28!1m20!1m1!1s0x47e6701f7e8337b5:0xa2cb58dd28914524!2m2!1d2.2930458!2d48.8560934!3m4!1m2!1d2.3122286!2d48.8490916!3s0x47e6702fa62d0bc5:0xd2d94ed604f2e5a0!3m4!1m2!1d2.3035972!2d48.8729816!3s0x47e66fc1755cf609:0x3c5040f902b41a5f!3m4!1m2!1d2.3235117!2d48.8581242!3s0x47e66e2ac3bca3ed:0x1c289763e3096e61!1m5!1m1!1s0x47e66e30d4668339:0xa9abf21c286d0767!2m2!1d2.3316014!2d48.8719697!3e0

On closer examination, you will see that the data param has lat-lng coordinates embedded in it. For example this !1d2.2930458!2d48.8560934 or !1d2.3122286!2d48.8490916. These are longitude latitude pairs representing various waypoints on the route. The longitude always starts with !1d and ends with !2d and the latitude starts with !2d and ends with !3.

Here is a small kotlin method to extract all the coordinates :

//https://stackoverflow.com/a/62191093/3090120
fun String?.indexesOf(pat: String, ignoreCase: Boolean = true): List<Int> =
        pat.toRegex(if (ignoreCase) setOf(RegexOption.IGNORE_CASE) else emptySet())
                .findAll(this ?: "")
                .map { it.range.first }
                .toList()

fun extractCoordinates(expandedUrl: String): List<LatLng> {
    val latLngList = arrayListOf<LatLng>()
    val indexes = expandedUrl.indexesOf("!1d")

indexes.forEach {
        val coordinatesStr = expandedUrl.substring(it + 3).substringBefore("!3").split("!2d")
        latLngList.add(LatLng(coordinatesStr[1].toDouble(), coordinatesStr[0].toDouble()))
    }

return latLngList
}

The result with this string would be [lat/lng: (48.8560934,2.2930458), lat/lng: (48.8490916,2.3122286), lat/lng: (48.8729816,2.3035972), lat/lng: (48.8581242,2.3235117), lat/lng: (48.8719697,2.3316014)]

Once we have all the lat-lng pairs we can simply fire off a Google Maps Directions API call and recreate the route in the link and export it as a GPX file.

https://stackoverflow.com/questions/69853742/how-to-extract-route-gpx-from-a-google-maps-route

Anonymous

How to extract route GPX from a Google Maps route?17.03.25

Information Epoch 1742936003