Implement average_speed in Trajectory class

fvh3t/core/gate.py

@@ -1,5 +1,6 @@
 from qgis.core import QgsGeometry
 
+
 class Gate:
     """
     A wrapper class around a QgsGeometry which represents a
@@ -12,4 +13,3 @@ def __init__(self, geom: QgsGeometry) -> None:
 
     def geometry(self) -> QgsGeometry:
         return self.__geom
-

fvh3t/core/trajectory.py

@@ -1,9 +1,12 @@
+import math
+
 from typing import NamedTuple
 
 from qgis.core import QgsGeometry, QgsPointXY, QgsVectorLayer, QgsWkbTypes
 
 from fvh3t.core.gate import Gate
 
+
 class TrajectoryNode(NamedTuple):
     """
     A simple data container representing one node in a
@@ -34,8 +37,27 @@ def intersects_gate(self, other: Gate) -> bool:
         return self.as_geometry().intersects(other.geometry())
 
     def average_speed(self) -> float:
-        # TODO: implement function
-        return 0.0
+        total_distance = 0.0
+        total_time = 0
+        for i in range(1, len(self.__nodes)):
+            current_node = self.__nodes[i]
+            previous_node = self.__nodes[i - 1]
+
+            distance = math.sqrt(
+                (current_node.point.x - previous_node.point.x) ** 2
+                + (current_node.point.y - previous_node.point.y) ** 2
+            )
+
+            time_difference = current_node.timestamp - previous_node.timestamp
+
+            total_distance += distance
+            total_time += time_difference
+
+        if total_time > 0:
+            return total_distance / total_time
+
+        else:
+            return 0.0
 
 
 class TrajectoryLayer:

tests/conftest.py

@@ -20,10 +20,23 @@
 from fvh3t.core.trajectory import Trajectory, TrajectoryNode
 from qgis.core import QgsGeometry, QgsPointXY
 
+
 @pytest.fixture
 def two_node_trajectory():
     return Trajectory((TrajectoryNode.from_coordinates(0, 0, 1000), TrajectoryNode.from_coordinates(0, 1, 2000)))
 
+
+@pytest.fixture
+def three_node_trajectory():
+    return Trajectory(
+        (
+            TrajectoryNode.from_coordinates(0, 0, 1000),
+            TrajectoryNode.from_coordinates(0, 1, 2000),
+            TrajectoryNode.from_coordinates(0, 2, 3000),
+        )
+    )
+
+
 @pytest.fixture
 def two_point_gate():
     return Gate(QgsGeometry.fromPolylineXY([QgsPointXY(-0.5, 0.5), QgsPointXY(0.5, 0.5)]))

tests/core/test_trajectory.py

@@ -2,9 +2,11 @@
 from fvh3t.core.gate import Gate
 from qgis.core import QgsGeometry, QgsPointXY
 
+
 def test_trajectory_as_geometry(two_node_trajectory: Trajectory) -> None:
     assert two_node_trajectory.as_geometry().asWkt() == "LineString (0 0, 0 1)"
 
+
 def test_trajectory_intersects_gate(two_node_trajectory):
     geom1 = QgsGeometry.fromPolylineXY([QgsPointXY(-0.5, 0.5), QgsPointXY(0.5, 0.5)])
     geom2 = QgsGeometry.fromPolylineXY([QgsPointXY(-1, -1), QgsPointXY(-2, -2)])
@@ -15,3 +17,7 @@ def test_trajectory_intersects_gate(two_node_trajectory):
     assert two_node_trajectory.intersects_gate(gate1)
     assert not two_node_trajectory.intersects_gate(gate2)
 
+
+def test_trajectory_average_speed(two_node_trajectory: Trajectory, three_node_trajectory: Trajectory):
+    assert two_node_trajectory.average_speed() == 0.001
+    assert three_node_trajectory.average_speed() == 0.001