diff --git a/src/components/project.vue b/src/components/project.vue
index 43ef053..d2dfcfe 100644
--- a/src/components/project.vue
+++ b/src/components/project.vue
@@ -273,6 +273,7 @@ export default {
 		},
 		addBaseMap(asBaseMap) {
 			if(asBaseMap.default_map) this.baseMap = asBaseMap.codename;
+			if(this.map.getSource(asBaseMap.codename) && this.map.getLayer(asBaseMap.codename)) return;
 			this.map.addSource(asBaseMap.codename, {
 				type: 'raster',
 				tiles: [asBaseMap.pattern],