Add chart1 and chart2 visualizations for UK data (HW 4)

flaskapp/routes.py

@@ -1,8 +1,15 @@
 from flask import render_template, flash, redirect, url_for, request
 from flaskapp import app, db
 from flaskapp.models import BlogPost, IpView, Day
+from flaskapp.models import UkData
 from flaskapp.forms import PostForm
 import datetime
+import matplotlib
+matplotlib.use('Agg') #Use non-GUI backend 
+import matplotlib.pyplot as plt 
+import io 
+import base64
+
 
 import pandas as pd
 import json
@@ -71,3 +78,57 @@ def before_request_func():
         db.session.add(ip_view)  # insert into the ip_view table
 
     db.session.commit()  # commit all the changes to the database
+
+@app.route('/chart1')
+def chart1():
+    data = UkData.query.all()
+    df = pd.DataFrame([d.__dict__ for d in data])
+
+    df['region'] = df['region'].str.strip()
+    df = df[~df['region'].isin(['Wales', 'Scotland'])]
+
+    if df.empty:
+        return "No English regions found in the data."
+
+    #Example chart: Voter turnout per region
+    turnout_by_region = df.groupby('region')['Turnout19'].mean()
+
+    fig, ax = plt.subplots()
+    turnout_by_region.plot(kind = 'bar', ax = ax)
+    ax.set_title("Average 2019 Turnout in English Regions")
+    ax.set_ylabel("Turnout (%)")
+
+    fig.tight_layout() #fix axis cropping
+
+    img = io.BytesIO()
+    fig.savefig(img, format = 'png')
+    img.seek(0)
+    plot_url = base64.b64encode(img.getvalue()).decode()
+
+    return render_template('chart1.html', plot_url = plot_url)
+
+@app.route('/chart2')
+@app.route('/chart2/<country>')
+def chart2(country = None):
+    data = UkData.query.all()
+    df = pd.DataFrame([d.__dict__ for d in data])
+
+    if country:
+        df = df[df['region'].str.lower() == country.lower()]
+
+    party_votes = df[['ConVote19', 'LabVote19', 'LDVote19']].mean()
+    party_votes.index = ['Conservative', 'Labour', 'Liberal Democrats']
+
+    fig, ax = plt.subplots()
+    party_votes.plot(kind='pie', ax = ax, autopct = '%1.1f%%')
+    ax.set_title(f"Average Vote Share{' in ' + country.title() if country else ''}")
+    ax.set_ylabel('')
+
+    fig.tight_layout() #fix axis cropping
+
+    img = io.BytesIO()
+    fig.savefig(img, format = 'png')
+    img.seek(0)
+    plot_url = base64.b64encode(img.getvalue()).decode()
+
+    return render_template('chart2.html', plot_url = plot_url)

flaskapp/templates/chart1.html

@@ -0,0 +1,2 @@
+<h2>Chart 1: Average Turnout by Region</h2>
+<img src="data:image/png;base64,{{ plot_url }}" />

flaskapp/templates/chart2.html

@@ -0,0 +1,2 @@
+<h2>Chart 2: Average Vote Share by Party</h2>
+<img src="data:image/png;base64,{{ plot_url }}" />