/** Base layers **/
// Layer: STAMEN
stamen = new ol.layer.Tile({
    source: new ol.source.Stamen({
        layer: 'toner'
    })
});
stamen.setZIndex(0);

// Layer: GOOGLE
tileSource = new ol.source.XYZ({
    url: 'https://mt1.google.com/vt/lyrs=p@129&hl=en&x={x}&y={y}&z={z}&s=Galileo'
});

google = new ol.layer.Tile({
    source: tileSource,
    zIndex: 0
});

// Layer: GOOGLE SATELLITE
tileSource_satellite = new ol.source.XYZ({
    url: 'https://mt1.google.com/vt/lyrs=s@129&hl=en&x={x}&y={y}&z={z}&s=Galileo'
});

google_satellite = new ol.layer.Tile({
    source: tileSource_satellite,
    zIndex: 0
});


// Layer: GOOGLE HYBRID
tileSource_hybrid = new ol.source.XYZ({
    url: 'https://mt1.google.com/vt/lyrs=y@129&hl=en&x={x}&y={y}&z={z}&s=Galileo'
});

google_hybrid = new ol.layer.Tile({
    source: tileSource_hybrid,
    zIndex: 0
});