feat(TimestampedGeoJson): support marker-only animation without redrawing paths

folium/plugins/timestamped_geo_json.py

@@ -47,6 +47,10 @@ class TimestampedGeoJson(JSCSSMixin, MacroElement):
         Used to construct the array of available times starting
         from the first available time. Format: ISO8601 Duration
         ex: 'P1M' 1/month, 'P1D' 1/day, 'PT1H' 1/hour, and 'PT1M' 1/minute
+    show_path: bool, default True
+        Whether to draw animated LineString paths. Set to False to animate
+        only the last-point markers when add_last_point=True. The source paths
+        are still used to determine timestamps and marker positions.
     duration: str, default None
         Period of time which the features will be shown on the map after their
         time has passed. If None, all previous times will be shown.
@@ -131,6 +135,14 @@ class TimestampedGeoJson(JSCSSMixin, MacroElement):
                     }
                 })
 
+            {% if not this.show_path %}
+            // Keep full source features for time indexing, but skip recreating
+            // their polylines in the animated frame layers.
+            geoJsonLayer.options.filter = function (feature) {
+                return feature.geometry.type !== "LineString";
+            };
+            {% endif %}
+
             var {{this.get_name()}} = L.timeDimension.layer.geoJson(
                 geoJsonLayer,
                 {
@@ -191,6 +203,7 @@ def __init__(
         time_slider_drag_update=False,
         duration=None,
         speed_slider=True,
+        show_path=True,
     ):
         super().__init__()
         self._name = "TimestampedGeoJson"
@@ -205,6 +218,7 @@ def __init__(
             self.embed = False
             self.data = data
         self.add_last_point = bool(add_last_point)
+        self.show_path = bool(show_path)
         self.period = period
         self.date_options = date_options
         self.duration = "undefined" if duration is None else '"' + duration + '"'

tests/plugins/test_timestamped_geo_json.py

@@ -197,3 +197,44 @@ def test_timestamped_geo_json():
 
     bounds = m.get_bounds()
     assert bounds == [[-53.0, -158.0], [50.0, 158.0]], bounds
+
+
+def test_timestamped_geo_json_can_animate_markers_without_paths():
+    data = {
+        "type": "FeatureCollection",
+        "features": [
+            {
+                "type": "Feature",
+                "geometry": {"type": "LineString", "coordinates": [[1, 2], [3, 4]]},
+                "properties": {
+                    "times": [1435708800000, 1435795200000],
+                    "icon": "marker",
+                },
+            }
+        ],
+    }
+
+    map_with_paths = folium.Map(location=[2, 1])
+    plugins.TimestampedGeoJson(data).add_to(map_with_paths)
+    original = map_with_paths.get_root().render()
+    assert "geoJsonLayer.options.filter" not in original
+
+    map_with_markers = folium.Map(location=[2, 1])
+    plugin = plugins.TimestampedGeoJson(
+        data,
+        show_path=False,
+        add_last_point=True,
+    ).add_to(map_with_markers)
+    html = map_with_markers.get_root().render()
+
+    # Initial GeoJSON must receive every LineString so it can index all times.
+    # The frame-layer filter is installed only afterwards, and suppresses
+    # creating a polyline while allowing the generated last-point marker.
+    initial_layer = html.index("var geoJsonLayer = L.geoJson(")
+    frame_filter = html.index("geoJsonLayer.options.filter = function")
+    animated_layer = html.index("L.timeDimension.layer.geoJson(")
+    assert initial_layer < frame_filter < animated_layer
+    assert 'feature.geometry.type !== "LineString"' in html
+    assert "addlastPoint: true" in html
+    assert '"coordinates": [[1, 2], [3, 4]]' in html
+    assert plugin.show_path is False