Fix polyline plot errors (#36)

There are two errors for polylines that have popped up on Sentry lately.
It seems that people have activities with either a single point, or
multiple points directly on top of eachother, which results in div/0
errors. This fixes those, and adds tests for the polyline visualisations
while I'm at it.

backend/active_statistics/statistics/images/polyline_grid.py

@@ -25,6 +25,7 @@ def create_images(activity_iterator: Iterable[Activity], path: str) -> None:
         )
         for activity in activity_iterator
         if activity.start_date_local is not None
+        and activity.map.summary_polyline is not None
     ]
     compact_activities.sort(key=lambda x: x.start_date_local)
 
@@ -118,13 +119,18 @@ def create_image(
     for encoded_polyline in encoded_polylines:
         polyline: Polyline = pl.decode(encoded_polyline)
 
-        # If the polyline has nothing in it, just return.
-        if not polyline:
+        if len(polyline) <= 1:
+            # I think we have ran into instances where people have ONLY activities with a single
+            # lat-long pair here, which means that the max cheby distance is 0, and then we do a
+            # divide by zero. So lets just continue if there is a single point, because lets be
+            # real, a single point is silly to plot.
             continue
 
         polyline = apply_equirectangular_approximation(polyline)
-        polyline = custom_scale_polyline(polyline)
-        polylines.append(polyline)
+        optional_polyline = custom_scale_polyline(polyline)
+
+        if optional_polyline is not None:
+            polylines.append(optional_polyline)
 
     if not polylines:
         return None
@@ -188,7 +194,7 @@ def equirectangular_approximation(lat, lon, reference_lat):
     return polyline
 
 
-def custom_scale_polyline(polyline: Polyline) -> Polyline:
+def custom_scale_polyline(polyline: Polyline) -> None | Polyline:
     """
     The goal here is to scale some arbitrary polyline into the center of a unit
     square. This will make it easier to place them all in the future.
@@ -206,6 +212,11 @@ def custom_scale_polyline(polyline: Polyline) -> Polyline:
     width = max_x - min_x
     height = max_y - min_y
 
+    # Handle the case where all points are in the same spot. To avoid a div/0
+    # error here, just return None because we can't scale this.
+    if max([height, width]) == 0:
+        return None
+
     # Calculate the scaling factors for x and y to fit the polyline into a unit square
     if width > height:
         scaling_factor = 1 / width

backend/active_statistics/statistics/images/polyline_overlay.py

@@ -98,7 +98,11 @@ def create_image(
         # If the polyline has nothing in it, just return.
         polyline = decode_polyline(encoded_polyline)
 
-        if len(polyline) == 0:
+        if len(polyline) <= 1:
+            # I think we have ran into instances where people have ONLY activities with a single
+            # lat-long pair here, which means that the max cheby distance is 0, and then we do a
+            # divide by zero. So lets just continue if there is a single point, because lets be
+            # real, a single point is silly to plot.
             continue
 
         polyline = apply_equirectangular_approximation(polyline)
@@ -117,6 +121,13 @@ def create_image(
         max_chebychev_distance(polyline) for polyline in polylines
     )
 
+    if max_all_max_chebychev_distances == 0:
+        # This can occur if a polyline is any number of points all at the exact
+        # same location, and that polyline if the only polyline that that
+        # activity (or possible all polylines for that activity have identical
+        # points.)  We just want to return if that's the case.
+        return None
+
     scaled_polylines = [
         aesthetically_scale_polyline(
             polyline, max_all_max_chebychev_distances, min([height, width])

backend/tests/test_visualisations/test_polyline_grid.py

@@ -0,0 +1,82 @@
+import shutil
+
+import pytest
+from active_statistics.statistics.images.polyline_grid import create_images
+from stravalib.model import Activity, PolylineMap
+from tests.factories.activity_factories import ActivityFactory
+
+
+@pytest.fixture(scope="function")
+def temp_directory(request, tmp_path_factory):
+    # Create a temporary directory
+    temp_dir = tmp_path_factory.mktemp("temp_directory")
+
+    # Define a finalizer to clean up the directory after the test
+    def cleanup_temp_directory():
+        # Delete the directory and its contents
+        shutil.rmtree(temp_dir)
+
+    # Add the finalizer to the request to ensure cleanup
+    request.addfinalizer(cleanup_temp_directory)
+
+    return temp_dir
+
+
+class TestPolylineGrid:
+    def test_no_activities(self, temp_directory) -> None:
+        activities: list[Activity] = []
+        create_images((_ for _ in activities), temp_directory)
+
+    def test_activities_with_no_polylines(self, temp_directory) -> None:
+        activities = [
+            ActivityFactory(
+                type="Run",
+                map=PolylineMap(id="123", polyline=None, summary_polyline=None),
+            ),
+        ]
+        create_images(activities, temp_directory)
+
+    def test_activities_with_blank_polylines(self, temp_directory) -> None:
+        activities: list[Activity] = [
+            ActivityFactory(
+                type="Run",
+                map=PolylineMap(id="123", polyline=None, summary_polyline=""),
+            ),
+        ]
+        create_images((_ for _ in activities), temp_directory)
+
+    def test_activities_with_single_point_polylines(self, temp_directory) -> None:
+        activities: list[Activity] = [
+            ActivityFactory(
+                type="Run",
+                map=PolylineMap(id="123", polyline=None, summary_polyline="??"),
+            ),
+        ]
+        create_images((_ for _ in activities), temp_directory)
+
+    def test_activities_with_multi_point_identical_polylines(
+        self, temp_directory
+    ) -> None:
+        # Yes, this polyline is from real data.
+        activities: list[Activity] = [
+            ActivityFactory(
+                type="Run",
+                map=PolylineMap(
+                    id="123", polyline=None, summary_polyline="fszfDwsbe\\??"
+                ),
+            ),
+        ]
+        create_images((_ for _ in activities), temp_directory)
+
+    def test_activities_with_normal_polylines(self, temp_directory) -> None:
+        activities: list[Activity] = [
+            ActivityFactory(
+                type="Run",
+                map=PolylineMap(
+                    id="123",
+                    polyline=None,
+                    summary_polyline="tdufD}|}d\C?e@Nm@\eAn@u@j@_Aj@i@b@q@\EN]HcAZyBdAWVcAt@g@Vs@n@{@j@c@r@mAnAW`@Mb@MVJR@Tw@jAGp@LtALl@RVTf@Vr@b@bBP`@FX?JCp@Jt@Vh@P^PTf@`@l@pABJ`@fA\t@~@hAd@`ARl@z@dBV^rA~AV\hBjDh@lA~BlC`@j@rCxERXdBbBbArAVf@jAjAXRb@LXPzA|ARJVD^TdAz@v@x@Rb@^l@x@`Az@t@dAl@vBvAjBtA`@^hBvAvA`Ap@j@dB`AlDlC~@n@hAh@hA\^Rd@\jAp@RFf@Df@Cf@BbB~@fAp@f@`@`@b@^Tf@Fr@Ah@OX[|@sBvAsDLc@d@eAHe@Hq@N_@FIFUAc@D{@DiEF}B?gBBsAD~CAfCErAEdEG~AJj@@h@GjAc@tD_@zAQf@Sd@{@rAIFa@RWDe@Ga@AWQM[[YWIkAk@s@g@{@g@k@[[Mi@[]IkAFSCWGiAi@{@c@eAs@cAa@mCgB}B}AeCoB{@g@mAcA_Am@uAkAeBgAiBoAc@_@a@c@e@_@}@_Aw@{A[a@u@o@a@WaA_@]Yy@}@w@_@]I_@Wk@i@eDeEWg@aBoB{@mAe@{@aBwBWg@y@gAqA{BqAgB{AeCi@u@sAmC[w@gAkBi@_BUe@w@mA{@iBKgA_@yAMq@Qi@q@_BKsAGc@Ak@Fe@JW`@m@Ie@Ng@PQZe@`@a@p@_AVi@bByAVYhCwAnAaAZO\Kb@Wd@O",
+                ),
+            ),
+        ]
+        create_images((_ for _ in activities), temp_directory)

backend/tests/test_visualisations/test_polyline_overlay.py

@@ -0,0 +1,82 @@
+import shutil
+
+import pytest
+from active_statistics.statistics.images.polyline_overlay import create_images
+from stravalib.model import Activity, PolylineMap
+from tests.factories.activity_factories import ActivityFactory
+
+
+@pytest.fixture(scope="function")
+def temp_directory(request, tmp_path_factory):
+    # Create a temporary directory
+    temp_dir = tmp_path_factory.mktemp("temp_directory")
+
+    # Define a finalizer to clean up the directory after the test
+    def cleanup_temp_directory():
+        # Delete the directory and its contents
+        shutil.rmtree(temp_dir)
+
+    # Add the finalizer to the request to ensure cleanup
+    request.addfinalizer(cleanup_temp_directory)
+
+    return temp_dir
+
+
+class TestPolylineOverlay:
+    def test_no_activities(self, temp_directory) -> None:
+        activities: list[Activity] = []
+        create_images((_ for _ in activities), temp_directory)
+
+    def test_activities_with_no_polylines(self, temp_directory) -> None:
+        activities = [
+            ActivityFactory(
+                type="Run",
+                map=PolylineMap(id="123", polyline=None, summary_polyline=None),
+            ),
+        ]
+        create_images((_ for _ in activities), temp_directory)
+
+    def test_activities_with_blank_polylines(self, temp_directory) -> None:
+        activities: list[Activity] = [
+            ActivityFactory(
+                type="Run",
+                map=PolylineMap(id="123", polyline=None, summary_polyline=""),
+            ),
+        ]
+        create_images((_ for _ in activities), temp_directory)
+
+    def test_activities_with_single_point_polylines(self, temp_directory) -> None:
+        activities: list[Activity] = [
+            ActivityFactory(
+                type="Run",
+                map=PolylineMap(id="123", polyline=None, summary_polyline="??"),
+            ),
+        ]
+        create_images((_ for _ in activities), temp_directory)
+
+    def test_activities_with_multi_point_identical_polylines(
+        self, temp_directory
+    ) -> None:
+        # Yes, this polyline is from real data.
+        activities: list[Activity] = [
+            ActivityFactory(
+                type="Run",
+                map=PolylineMap(
+                    id="123", polyline=None, summary_polyline="fszfDwsbe\\??"
+                ),
+            ),
+        ]
+        create_images((_ for _ in activities), temp_directory)
+
+    def test_activities_with_normal_polylines(self, temp_directory) -> None:
+        activities: list[Activity] = [
+            ActivityFactory(
+                type="Run",
+                map=PolylineMap(
+                    id="123",
+                    polyline=None,
+                    summary_polyline="tdufD}|}d\C?e@Nm@\eAn@u@j@_Aj@i@b@q@\EN]HcAZyBdAWVcAt@g@Vs@n@{@j@c@r@mAnAW`@Mb@MVJR@Tw@jAGp@LtALl@RVTf@Vr@b@bBP`@FX?JCp@Jt@Vh@P^PTf@`@l@pABJ`@fA\t@~@hAd@`ARl@z@dBV^rA~AV\hBjDh@lA~BlC`@j@rCxERXdBbBbArAVf@jAjAXRb@LXPzA|ARJVD^TdAz@v@x@Rb@^l@x@`Az@t@dAl@vBvAjBtA`@^hBvAvA`Ap@j@dB`AlDlC~@n@hAh@hA\^Rd@\jAp@RFf@Df@Cf@BbB~@fAp@f@`@`@b@^Tf@Fr@Ah@OX[|@sBvAsDLc@d@eAHe@Hq@N_@FIFUAc@D{@DiEF}B?gBBsAD~CAfCErAEdEG~AJj@@h@GjAc@tD_@zAQf@Sd@{@rAIFa@RWDe@Ga@AWQM[[YWIkAk@s@g@{@g@k@[[Mi@[]IkAFSCWGiAi@{@c@eAs@cAa@mCgB}B}AeCoB{@g@mAcA_Am@uAkAeBgAiBoAc@_@a@c@e@_@}@_Aw@{A[a@u@o@a@WaA_@]Yy@}@w@_@]I_@Wk@i@eDeEWg@aBoB{@mAe@{@aBwBWg@y@gAqA{BqAgB{AeCi@u@sAmC[w@gAkBi@_BUe@w@mA{@iBKgA_@yAMq@Qi@q@_BKsAGc@Ak@Fe@JW`@m@Ie@Ng@PQZe@`@a@p@_AVi@bByAVYhCwAnAaAZO\Kb@Wd@O",
+                ),
+            ),
+        ]
+        create_images((_ for _ in activities), temp_directory)

captions.json

@@ -0,0 +1 @@
+{"Run.png": "All Run activities overlaid as if they have the same starting point.", "Run_animation.gif": "An animation of overlaid Run activities."}