问图标必须在不同的视图级别上可见

EN

var touristicIcons = new ol.layer.Vector({
    source: touristicIconsSource,
    minResolution: xx
    maxResolution: xx
});

// Repeat for airports layer, with different resolutions

map.getView().on('change:resolution', function (event) {
    var view = event.currentTarget;
    console.log('Zoom: ' + view.getZoom() + 
                ', resolution: ' + view.getResolution());
});