add gantt chart for pv site data availability

examples/india_gantt_chart.py

@@ -0,0 +1,81 @@
+"""Gantt chart for India PV systems. This shows where there are gaps in the data."""
+import os
+import pandas as pd
+import numpy as np
+import plotly.express as px
+import h5py
+
+# load hdf file with the generation data for each system
+pv_data_hdf = os.environ.get("PV_DATA_HDF")
+
+# these are the current systems with some data in the hdf file for india
+systems_with_data = [
+    "56151",
+    "56709",
+    "58780",
+    "59687",
+    "59710",
+    "60294",
+    "60602",
+    "66634",
+    "71120",
+    "72742",
+    "73347",
+    "77684",
+    "77710",
+    "78186",
+    "79612",
+    "81408",
+    "82081",
+    "85738",
+    "86244",
+    "87410",
+    "90559",
+    "91554",
+    "97094",
+    "99833",
+    "100451",
+]
+
+
+pv_systems = []
+
+# read the hdf file and get start and end dates of available data per site
+with h5py.File(pv_data_hdf, "r") as f:
+    # loop through each pv system in the hdf file
+    for system_id in systems_with_data:
+        df = pd.DataFrame(np.array(f["timeseries"][system_id]["table"]))
+        df["index"] = pd.to_datetime(df["index"], unit="ns")
+        df = df[df["index"] > pd.Timestamp("2018-01-01")]
+        # set a value for the end date otherwise it registers as NaT
+        end_date = df["index"].iloc[-1]
+        df["index_difference"] = df["index"].diff()
+        # get startpoints of gaps in the data
+        df = df[df["index_difference"] > pd.Timedelta("1D")]
+        # get endpoints of gaps by looking at the difference between indexes
+        df["previous_endpoint"] = df["index"] - df["index_difference"]
+        df["endpoints"] = df["previous_endpoint"].shift(-1)
+        # set the last endpoint to the end date otherwise it registers as NaT
+        if len(df["endpoints"]) > 0:
+            df["endpoints"].iloc[-1] = end_date
+
+        # make a dictionary for the gantt chart to plot
+        # loop over the start and end dates and add to start_end_data dictionary
+        for index, row in df.iterrows():
+            start_end_data = {}
+            start_end_data["System ID"] = system_id
+            start_end_data["Start"] = row["index"]
+            start_end_data["Finish"] = row["endpoints"]
+
+            pv_systems.append(start_end_data)
+
+    # plot the data as gantt chart in plotly
+    fig = px.timeline(
+        pv_systems,
+        x_start="Start",
+        x_end="Finish",
+        y="System ID",
+        color="System ID",
+        title="Gantt Chart of PV Systems in India",
+    )
+    fig.show()