HW5 – Building Inventory Visualizations

Links

The Data

The Analysis (Notebook)

Plot 1: Top Agencies by Total Square Footage

The first plot summarizes which Illinois agencies manage the most building space. To create this visualization, I grouped the building inventory data by agency and summed the “Square Footage” field, then filtered to the top ten agencies by total square footage so the y-axis remains readable. The bar chart encodes total square footage as a quantitative x-axis, and agency names as a nominal y-axis sorted in descending order. I used a sequential colormap to reinforce the magnitude differences. These transformations and encoding choices make it easy to compare which agencies control the most building area across the state.

Plot 2: Total Square Footage by Construction Decade (Interactive by Usage)

The second plot shows how building space is distributed across construction decades for different usage types. I converted the “Year Constructed” column into numeric, filtered unrealistic values, and created a “decade” field by flooring years to the nearest decade. I then aggregated total square footage per decade and usage description, limiting the visualization to the top usage categories for clarity. The bar chart encodes decade on the x-axis, total square footage on the y-axis, and colors bars by decade. Tooltips reveal decade, usage type, and square footage.

The plot includes a dropdown parameter that filters the chart by usage category. When the user selects a usage type, only buildings of that type are shown across decades. This interactivity goes beyond pan/zoom by allowing viewers to explore patterns category-by-category, avoiding clutter and making it easier to understand construction trends for specific building purposes.