update app.py

app.py

@@ -47,6 +47,7 @@ Future Improvements:
 # Visualization 2: Relationship Between Year Constructed and Square Footage
 # This scatter plot explores the relationship between the year a building was constructed and its square footage.
 # Points are color-coded based on the building's operational status, with tooltips providing additional details.
+# Remove rows where 'Year Constructed' is missing (NaN)
 filtered_data = data.dropna(subset=['Year Constructed'])
 
 # Visualization 2: Relationship Between Year Constructed and Square Footage
@@ -55,7 +56,10 @@ scatter_plot = (
     alt.Chart(filtered_data)
     .mark_circle(size=60)
     .encode(
-        x=alt.X("Year Constructed:Q", title="Year Constructed"), scale=alt.Scale(domain=[1700, filtered_data['Year Constructed'].max()])
+        x=alt.X(
+            "Year Constructed:Q",
+            title="Year Constructed",
+            scale=alt.Scale(domain=[1700, filtered_data['Year Constructed'].max()])
         ),
         y=alt.Y("Square Footage:Q", title="Square Footage"),
         color=alt.Color("Bldg Status:N", title="Building Status"),
@@ -74,6 +78,7 @@ st.altair_chart(scatter_plot, use_container_width=True)
 st.text("""
 This scatter plot highlights the relationship between the year a building was constructed and its square footage. 
 Design choices include:
+- The x-axis starts at 1700 to focus on relevant construction years.
 - Points are color-coded by building status to differentiate operational buildings from others.
 - Tooltips provide additional information about each building for interactive exploration.
 Future Improvements: