Fix parliamentary constituency impacts

Author: nikhilwoodruff

policyengine/outputs/macro/comparison/local_areas/parliamentary_constituencies.py

@@ -0,0 +1,165 @@
+from policyengine import Simulation
+import pandas as pd
+from policyengine.utils.huggingface import download
+import plotly.express as px
+from policyengine.utils.charts import *
+
+
+def parliamentary_constituencies(
+        simulation: Simulation, 
+        chart: bool = False, 
+        variable: str = None,
+        aggregator: str = None,
+        relative: bool = None,
+    ) -> dict:
+    if not simulation.options.get("include_constituencies"):
+        return {}
+
+    if chart:
+        return heatmap(
+            simulation=simulation,
+            variable=variable,
+            aggregator=aggregator,
+            relative=relative,
+        )
+
+    constituency_baseline = simulation.calculate(
+        "macro/baseline/gov/local_areas/parliamentary_constituencies"
+    )
+    constituency_reform = simulation.calculate(
+        "macro/reform/gov/local_areas/parliamentary_constituencies"
+    )
+
+    result = {}
+
+    for constituency in constituency_baseline:
+        result[constituency] = {}
+        for key in constituency_baseline[constituency]:
+            result[constituency][key] = {
+                "change": constituency_reform[constituency][key]
+                - constituency_baseline[constituency][key],
+                "baseline": constituency_baseline[constituency][key],
+                "reform": constituency_reform[constituency][key],
+            }
+
+    return result
+
+
+
+def heatmap(
+    simulation: Simulation,
+) -> dict:
+    if not simulation.options.get("include_constituencies"):
+        return {}
+
+    options = {}
+
+    if variable is not None:
+        options["variables"] = [variable]
+    if aggregator is not None:
+        options["aggregator"] = aggregator
+
+    constituency_baseline = simulation.calculate(
+        "macro/baseline/gov/local_areas/parliamentary_constituencies",
+        **options,
+    )
+    constituency_reform = simulation.calculate(
+        "macro/reform/gov/local_areas/parliamentary_constituencies", **options
+    )
+
+    result = {}
+
+    constituency_names_file_path = download(
+        repo="policyengine/policyengine-uk-data",
+        repo_filename="constituencies_2024.csv",
+        local_folder=None,
+        version=None,
+    )
+    constituency_names = pd.read_csv(constituency_names_file_path)
+
+    if variable is None:
+        variable = "household_net_income"
+    if relative is None:
+        relative = True
+
+    for constituency in constituency_baseline:
+        if relative:
+            result[constituency] = (
+                constituency_reform[constituency][variable]
+                / constituency_baseline[constituency][variable]
+                - 1
+            )
+        else:
+            result[constituency] = (
+                constituency_reform[constituency][variable]
+                - constituency_baseline[constituency][variable]
+            )
+
+    x_range = constituency_names["x"].max() - constituency_names["x"].min()
+    y_range = constituency_names["y"].max() - constituency_names["y"].min()
+    # Expand x range to preserve aspect ratio
+    expanded_lower_x_range = -(y_range - x_range) / 2
+    expanded_upper_x_range = x_range - expanded_lower_x_range
+    constituency_names.x = (
+        constituency_names.x - (constituency_names.y % 2 == 0) * 0.5
+    )
+    constituency_names["Relative change"] = (
+        pd.Series(list(result.values()), index=list(result.keys()))
+        .loc[constituency_names["name"]]
+        .values
+    )
+
+    label = simulation.baseline.tax_benefit_system.variables[variable].label
+
+    fig = px.scatter(
+        constituency_names,
+        x="x",
+        y="y",
+        color="Relative change",
+        hover_name="name",
+        title=f"{'Relative change' if relative else 'Change'} in {label} by parliamentary constituency",
+    )
+
+    format_fig(fig)
+
+    # Show hexagons on scatter points
+
+    fig.update_traces(
+        marker=dict(
+            symbol="hexagon", line=dict(width=0, color="lightgray"), size=15
+        )
+    )
+    fig.update_layout(
+        xaxis_tickvals=[],
+        xaxis_title="",
+        yaxis_tickvals=[],
+        yaxis_title="",
+        xaxis_range=[expanded_lower_x_range, expanded_upper_x_range],
+        yaxis_range=[
+            constituency_names["y"].min(),
+            constituency_names["y"].max(),
+        ],
+    ).update_traces(marker_size=10).update_layout(
+        xaxis_range=[30, 85], yaxis_range=[-50, 2]
+    )
+
+    x_min = fig.data[0]["marker"]["color"].min()
+    x_max = fig.data[0]["marker"]["color"].max()
+    max_abs = max(abs(x_min), abs(x_max))
+
+    fig.update_layout(
+        coloraxis=dict(
+            cmin=-max_abs,
+            cmax=max_abs,
+            colorscale=[
+                [0, DARK_GRAY],
+                [0.5, "lightgray"],
+                [1, BLUE],
+            ],
+            colorbar=dict(
+                tickformat=".0%" if relative else ",.0f",
+            ),
+        )
+    )
+
+    return fig