Add bar size scaling when zooming on map

src/PointMap.js

@@ -9,7 +9,7 @@ import Typography from '@material-ui/core/Typography';
 
 import { get_color_spectrum, get_undef_color } from './utils/lam-station'
 
-const polygon_size = 0.01
+const polygon_size = 0.50
 const polygon_size_lat = polygon_size * 2
 const polygon_size_lon = polygon_size
 
@@ -304,11 +304,14 @@ class PointMap extends Component {
         getFillColor: d => d.get_color(),
         getPolygon: d => {
           let [lat, lon] = d.coordinates;
+          let zoom = this.state.viewport.zoom;
+          let pol_lat = polygon_size_lat / (2 ** zoom);
+          let pol_lon = polygon_size_lon / (2 ** zoom);
           let coords = [
-            [lat + -polygon_size_lat, lon + polygon_size_lon],
-            [lat + polygon_size_lat, lon + polygon_size_lon],
-            [lat + polygon_size_lat, lon + -polygon_size_lon],
-            [lat + -polygon_size_lat, lon + -polygon_size_lon]
+            [lat + -pol_lat, lon + pol_lon],
+            [lat + pol_lat, lon + pol_lon],
+            [lat + pol_lat, lon + -pol_lon],
+            [lat + -pol_lat, lon + -pol_lon]
           ];
           return coords;
         },