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Heatmap Visualization of Tax Rate Changes in Thunder Bay from 2008 to 2021

In this post, we'll explore tax rate changes in the city of Thunder Bay from 2008 to 2021 (source) from Thunder Bay's Open Data Portal. To help us understand these changes, we'll use a heatmap visualization. The visualization provides unique insights into our data which “Contains information licensed under the Open Data Licence – The Corporation of the City of Thunder Bay.”

Heatmap of Tax Rates Over Time

The heatmap uses colour intensity to show the tax rate for each category over the years. The x-axis represents years and separates the years by "full service", "education" and "municipal" (the first set of years being "full service" from 2008 to 2021, the second set of years being "education" and the third set being "municipal"). Thus, collectively, "full service" = "education" + "municipal". The y-axis represents different tax rate categories. Each cell's colour in the grid corresponds to the tax rate value for that year and category, with darker colours indicating higher tax rates. The heatmap allows us to quickly see trends over time and across different categories. For example, we can see that some categories, such as 'FARMLAND RATE IN THE DOLLAR', have remained relatively stable and low over time, while others, like 'RESIDENTIAL RATE IN THE DOLLAR', have shown a clear upward trend.

The heatmap reveals several insights about the tax rate changes in Thunder Bay:

  1. Overall Increase in Tax Rates: There is a general trend of increasing tax rates from 2008 to 2021 across multiple categories. This is evident from the gradual shift from lighter to darker shades moving from left to right across the heatmap.

  2. Stability in Some Categories: Some tax categories such as 'FARMLAND RATE IN THE DOLLAR' have relatively lighter colours throughout the years, indicating that these rates have remained relatively stable and low over time.

  3. Varied Increase Across Categories: Other categories like 'RESIDENTIAL RATE IN THE DOLLAR', 'MULTI-RES RATE IN THE DOLLAR', and 'LARGE INDUSTRIAL RATE IN THE DOLLAR' show a clear upward trend, as indicated by the progressively darker colours. This suggests that these categories have experienced more significant tax increases over time compared to others.


The heatmap allows us to quickly spot overall trends and variations across categories and provides a comprehensive view of the tax rate changes in Thunder Bay from 2008 to 2021. While there's an overall trend of increasing tax rates, the magnitude and pace of these increases vary across categories. Policymakers, stakeholders, and residents can use this information to understand past trends and potentially predict future ones, aiding in planning and decision-making.

Stay tuned for more data visualizations and insights on our blog!


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