make only maxele and obs layers visible by default

this is accomplished by offloading the
determining of default layer state to a new function,
`newLayerDefaultState`, that looks at the layer object.

src/components/map/default-layers.js

@@ -4,6 +4,22 @@ import { CircleMarker } from 'leaflet';
 import { useLayers } from '@context';
 import { markClicked } from '@utils/map-utils';
 
+const newLayerDefaultState = layer => {
+    console.log(layer.properties.product_type)
+    const { product_type } = layer.properties
+
+    if (['obs', 'maxele63'].includes(product_type)) {
+        return ({
+            visible: true
+        })
+    }
+
+    return ({
+        visible: false
+    });
+};
+
+
 export const DefaultLayers = () => {
 
     const [obsData, setObsData] = useState("");
@@ -92,9 +108,7 @@ export const DefaultLayers = () => {
                 if (layer)
                     layer_list.push({
                         ...layer,
-                        state: {
-                            visible: true,
-                        }
+                        state: newLayerDefaultState(layer)
                     });
 
                     // TODO: do we really need to do this here??!