Multiple markers - Same coordinates

Question

I'm having some troubles trying to display 2 different markers placed at exactly the same coordinates.

The case is: we are displaying stores, and some of them are placed at the same building (ie. a mall), so, they are different stores but shares the same ubication/coordinates.

Our json source content looks like this:

  {
     "properties" : {
        "id" : "1",
        "name" : "Store 1"
     },
     "geometry" : {
        "coordinates" : [-70.66667, -33.45],
        "type" : "Point"
     }
  },
  {
     "properties" : {
        "id" : "2",
        "name" : "Store 2"
     },
     "geometry" : {
        "coordinates" : [-70.66667, -33.45],
        "type" : "Point"
     }
  }

The thing is, just one of them gets displayed.

My question is, is there an out of the box solution for this use-case? Or should we implement our own solution ?

Thanks in advance!

Midstream

Answer 1

If you are using the Marker class from mapbox-gl, you can just apply standard CSS transform to offset the marker.

Another solution would be something refered to as "spider marker":

• https://bewithjonam.github.io/mapboxgl-spiderifier/docs/index.html
• https://github.com/bewithjonam/mapboxgl-spiderifier

Kurtkurth

Thanks! That's exactly what we were looking for :) – Midstream

Answer 2

One solution is setting an offset to the markers with same coordinates. This will put markers with same coordinates at the same height next to each other:

for (const marker of markers) {
    // get all markers with the same coordinates
    const sameMarkers = markers.filter(m => m.lat === marker.lat && m.lon === marker.lon);

    // if there is more than one marker with the same coordinates
    if (sameMarkers.length > 1) {
        // get the index of the current marker
        const index = sameMarkers.indexOf(marker);

        // calculate the offset for the current marker
        const offset = 32 * (index - (sameMarkers.length - 1) / 2);

        // set the offset
        marker.setOffset([offset, 0]);
    }
}

Parasang