add taz-stop walk time estimation method

lasso/mtc.py

@@ -3151,3 +3151,81 @@ def _calculate_impedance(x):
 
     # optional return df: result_maz_trn_stops, shortest_paths_fail
     return est_maz_walk_time
+
+
+def estimate_transit_taz_connectors(
+    est_maz_walk_time: pd.DataFrame = None,
+    direction: str = "access",
+    trn_trip_list: pd.DataFrame = None,
+    parameters=None,
+):
+    # specify direction-specific variables
+    if direction == "access":
+        dir_col_maz = "from_maz"
+        dir_col_taz = "from_taz"
+    else:
+        dir_col_maz = "to_maz"
+        dir_col_taz = "to_taz"
+
+    # calculate maz-scale transit demand
+    maz_demand = (
+        trn_trip_list.groupby(["skim_set", "time_period", dir_col_maz])
+        .size()
+        .reset_index(name="maz_demand")
+    )
+
+    # add taz info to maz_demand
+    maz_taz_lookup = pd.read_csv(parameters.taz_maz_crosswalk_file)
+    maz_demand = (
+        pd.merge(
+            maz_demand,
+            maz_taz_lookup[["MAZ_ORIGINAL", "TAZ_ORIGINAL"]],
+            how="left",
+            left_on=dir_col_maz,
+            right_on="MAZ_ORIGINAL",
+        )
+        .drop(columns=["MAZ_ORIGINAL"])
+        .rename(columns={"TAZ_ORIGINAL": dir_col_taz})
+    )
+
+    # calculate taz-scale transit demand
+    taz_demand = (
+        maz_demand.groupby(["skim_set", "time_period", dir_col_taz])["maz_demand"]
+        .agg("sum")
+        .reset_index(name="taz_demand")
+    )
+
+    # calculate share of maz transit demand in its corresponding taz
+    maz_demand = pd.merge(
+        maz_demand, taz_demand, how="left", on=["skim_set", "time_period", dir_col_taz]
+    )
+
+    maz_demand["maz_demand_weight"] = maz_demand["maz_demand"] / maz_demand["taz_demand"]
+
+    # add weight info to est_maz_walk_time df
+    est_maz_walk_time = pd.merge(
+        est_maz_walk_time,
+        maz_demand[["skim_set", "time_period", dir_col_maz, dir_col_taz, "maz_demand_weight"]],
+        how="left",
+        on=["skim_set", "time_period", dir_col_maz],
+    )
+
+    # drop records w/o weight info (means w/o maz transit demand)
+    est_maz_walk_time = est_maz_walk_time[~est_maz_walk_time["maz_demand_weight"].isnull()]
+    est_maz_walk_time[dir_col_taz] = est_maz_walk_time[dir_col_taz].astype(int)
+
+    # calculated weighted walk time
+    est_maz_walk_time["weighted_time"] = (
+        est_maz_walk_time[f"est_maz_walk_{direction}_min"] * est_maz_walk_time["maz_demand_weight"]
+    )
+
+    est_taz_walk_time = (
+        est_maz_walk_time.groupby(["skim_set", "time_period", dir_col_taz])["weighted_time"]
+        .agg("sum")
+        .reset_index(name=f"est_taz_walk_{direction}_min")
+    )
+    est_taz_walk_time[f"est_taz_walk_{direction}_min"] = est_taz_walk_time[
+        f"est_taz_walk_{direction}_min"
+    ].round(3)
+
+    return est_taz_walk_time