diff --git a/js/lib/provider/MapTile.js b/js/lib/provider/MapTile.js
index aac2565..bccacb2 100644
--- a/js/lib/provider/MapTile.js
+++ b/js/lib/provider/MapTile.js
@@ -65,7 +65,7 @@ export class MapTileView extends provider.ProviderView {
       var format = this.model.get('format');
       var options = {}
       if (this.model.get('additional_params')) {
-        options['additionalParameters'] = this.model.get('additional_params');
+        Object.assign(options, this.model.get('additional_params'));
       }
       this.obj = mapTiler.createTileProvider(TileType, scheme, TileSize, format, options);
     });