add tutorial for two traces on plotly map

Author: betaBison

notebooks/tutorials/visualizations.ipynb

@@ -247,6 +247,29 @@
     "fig = glp.plot_map(state_estimate)\n",
     "fig.show()"
    ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "287beec9",
+   "metadata": {},
+   "source": [
+    "You can plot multiple data traces on the same graph as long as the `*` in the `lat_*_deg` and `lon_*_deg` fields is different for each data trace."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "bd7fbb4b",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# load a separate data file\n",
+    "!wget https://raw.githubusercontent.com/Stanford-NavLab/gnss_lib_py/main/data/unit_test/android_2021/Pixel4_ground_truth.csv --quiet -O \"Pixel4_truth.csv\"\n",
+    "truth_data_second_trace = glp.AndroidGroundTruth2021(\"Pixel4_truth.csv\")\n",
+    "\n",
+    "fig = glp.plot_map(state_estimate, truth_data_second_trace)\n",
+    "fig.show()"
+   ]
   }
  ],
  "metadata": {