New param agg for to_traj_gdf

movingpandas/tests/test_trajectory_collection.py

@@ -291,3 +291,37 @@ def test_to_traj_gdf(self):
         expected_line_gdf = GeoDataFrame(df2, crs=CRS_METRIC)
 
         assert_frame_equal(traj_gdf, expected_line_gdf)
+
+    def test_to_traj_gdf_aggregate(self):
+        temp_df = self.geo_df.drop(columns=["val2"])
+        tc = TrajectoryCollection(temp_df, "id")
+        traj_gdf = tc.to_traj_gdf(agg={"obj": "mode", "val":["min", "max"]})
+        print(traj_gdf)
+        rows = [
+            {
+                "traj_id": 1,
+                "start_t": datetime(2018, 1, 1, 12, 0, 0),
+                "end_t": datetime(2018, 1, 1, 14, 15, 0),
+                "geometry": LineString([(0, 0), (6, 0), (6, 6), (9, 9)]),
+                "length": 12 + sqrt(18),
+                "direction": 45.0,
+                "obj_mode": "A",
+                "val_min": 2,
+                "val_max": 9
+            },
+            {
+                "traj_id": 2,
+                "start_t": datetime(2018, 1, 1, 12, 0, 0),
+                "end_t": datetime(2018, 1, 2, 13, 15, 0),
+                "geometry": LineString([(10, 10), (16, 10), (16, 16), (190, 10)]),
+                "length": 12 + sqrt(174 * 174 + 36),
+                "direction": 90.0,
+                "obj_mode": "A",
+                "val_min": 3,
+                "val_max": 10
+            },
+        ]
+        df2 = pd.DataFrame(rows)
+        expected_line_gdf = GeoDataFrame(df2, crs=CRS_METRIC)
+
+        assert_frame_equal(traj_gdf, expected_line_gdf)

movingpandas/trajectory.py

@@ -7,6 +7,7 @@
 from datetime import datetime
 from pandas import DataFrame, to_datetime, Series
 from pandas.core.indexes.datetimes import DatetimeIndex
+from pandas import Series 
 from geopandas import GeoDataFrame
 from geopy.distance import geodesic
 
@@ -413,7 +414,7 @@ def to_line_gdf(self):
         line_gdf.set_geometry("geometry", inplace=True)
         return line_gdf
 
-    def to_traj_gdf(self, wkt=False):
+    def to_traj_gdf(self, wkt=False, agg=False):
         """
         Return a GeoDataFrame with one row containing the trajectory as a
         single LineString.
@@ -432,6 +433,15 @@ def to_traj_gdf(self, wkt=False):
         }
         if wkt:
             properties["wkt"] = self.to_linestringm_wkt()
+        if agg:
+            for key, value in agg.items():
+                if type(value) != list: 
+                    value = [value]
+                for v in value: 
+                    if v == "mode":
+                        properties[f"{key}_{v}"] = self.df.agg({key: Series.mode})[key][0]
+                    else: 
+                        properties[f"{key}_{v}"] = self.df.agg({key: v})[key]
         df = DataFrame([properties])
         traj_gdf = GeoDataFrame(df, crs=self.crs)
         return traj_gdf

movingpandas/trajectory_collection.py

@@ -136,7 +136,7 @@ def to_line_gdf(self):
         gdf.reset_index(drop=True, inplace=True)
         return gdf
 
-    def to_traj_gdf(self, wkt=False):
+    def to_traj_gdf(self, wkt=False, agg=False):
         """
         Return a GeoDataFrame with one row per Trajectory within the
         TrajectoryCollection
@@ -145,7 +145,7 @@ def to_traj_gdf(self, wkt=False):
         -------
         GeoDataFrame
         """
-        gdfs = [traj.to_traj_gdf(wkt) for traj in self.trajectories]
+        gdfs = [traj.to_traj_gdf(wkt, agg) for traj in self.trajectories]
         gdf = concat(gdfs)
         gdf.reset_index(drop=True, inplace=True)
         return gdf

tutorials/6-trajectory-metrics.ipynb

@@ -0,0 +1,134 @@
+{
+ "cells": [
+  {
+   "attachments": {},
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Computing Trajectory Metrics\n",
+    "\n",
+    "<img align=\"right\" src=\"https://anitagraser.github.io/movingpandas/assets/img/movingpandas.png\">\n",
+    "\n",
+    "[![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/anitagraser/movingpandas/main?filepath=tutorials/6-trajectory-metrics.ipynb)\n",
+    "\n",
+    "**<p style=\"color:#e31883\">This notebook demonstrates the current development version of MovingPandas.</p>**\n",
+    "\n",
+    "For tutorials using the latest release visit https://github.com/anitagraser/movingpandas-examples.\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import urllib\n",
+    "import os\n",
+    "import numpy as np\n",
+    "import pandas as pd\n",
+    "import geopandas as gpd\n",
+    "from shapely.geometry import Point, LineString, Polygon, MultiPoint\n",
+    "from datetime import datetime, timedelta\n",
+    "from holoviews import opts, dim\n",
+    "\n",
+    "import sys\n",
+    "sys.path.append(\"..\")\n",
+    "import movingpandas as mpd\n",
+    "mpd.show_versions()\n",
+    "\n",
+    "import warnings\n",
+    "warnings.simplefilter(\"ignore\")"
+   ]
+  },
+  {
+   "attachments": {},
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Raw AIS trajectories"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "gdf = gpd.read_file('data/demodata_ais.gpkg')\n",
+    "gdf['t'] = pd.to_datetime(gdf['Timestamp'], format='%d/%m/%Y %H:%M:%S')\n",
+    "gdf = gdf[gdf.SOG>0]\n",
+    "gdf"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "traj_collection = mpd.TrajectoryCollection(gdf, 'MMSI', min_length=100, t='t')\n",
+    "print(\"Finished creating {} trajectories\".format(len(traj_collection)))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "trips = mpd.ObservationGapSplitter(traj_collection).split(gap=timedelta(minutes=30))\n",
+    "print(\"Extracted {} individual trips from {} continuous vessel tracks\".format(len(trips), len(traj_collection)))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "traj_gdf = trips.to_traj_gdf(agg={\"ShipType\": \"mode\", \"MMSI\": \"mode\", \"SOG\": [\"min\", \"max\"]})\n",
+    "traj_gdf"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": []
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "movingpandas",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.9.13"
+  },
+  "vscode": {
+   "interpreter": {
+    "hash": "e083ffb052fc3090335b68330fa2108e4b62c90ad12f6dc729a484d53ff96ca7"
+   }
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 4
+}