how to know layer type from mapbox vector tile source

Question

Given a Mapbox tile source and a layer-name, how do I know this layer's type is (point, line, polygon)?

I want know the feature type ahead of time before I add the layer to a map (with map.addLayer)

if (layer-type 'point'){
    // for point only
    map.addLayer({
        type: circle
    }
} else {
    // for both lineString and polygon
    map.addLayer({
        type: line
    }
}

hoogw hoogw · Accepted Answer · 2019-06-06T22:46:11

I kind find a way to solve this problem.

Reference https://docs.mapbox.com/mapbox-gl-js/example/multiple-geometries/

Add multiple geometries from one GeoJSON source,

The key is:

you add all 3 layer for point, line, polygon, with 3 different layer-id each layer, you use filter for that type only

        map.addLayer(
                "type": fill
                "filter": ["==", "$type", "Polygon"]
                 )

         map.addLayer(
                "type": line
                "filter": ["==", "$type", "LingString"]
                 )

         map.addLayer(
                "type": Circle, // or symbol
                "filter": ["==", "$type", "Point"]
                 )

I have a complete code at: https://github.com/hoogw/arcgis_viewer/blob/master/public/javascripts/pbf/mapbox_common_share.js

how to know layer type from mapbox vector tile source

1 Answers