Data Methodology

Lot Depths and Frontages

At Ratio.City, we provide more than just raw parcel geometry - we extract meaningful measurements that enable planners, designers, and developers to make informed decisions. For some municipalities, two key values we calculate are frontage and depth. This methodology outlined below is applied to parcels in Barrie, Oshawa, Mississauga, London, and Toronto. Because parcels are often irregularly shaped, we apply a consistent geometric method to estimate these values with accuracy.

Note: Where frontage and depth values are available and provided by a municipality, we use this data directly.
This includes; New Westminster B.C, Windsor ON, and St. John’s NL.

The Idea: “Effective Rectangle” 

To simplify things, we represent each parcel as an “effective rectangle”, a shape that has the same area and perimeter as the actual lot. From this, we can define two useful dimensions: 

• Frontage = typically the shorter side (usually street-facing) 

• Depth = the longer side (extends away from the street) 

Here’s how we do it: 

Figuring Out Dimensions from Area & Perimeter 

With area and perimeter known, we work backwards to solve for frontage and depth using geometry. 

• Area = frontage × depth 

• Perimeter = 2 × (frontage + depth) 

Using those values, we isolate frontage with a formula that uses a quarter of the perimeter and a square root term (involving both perimeter and area). Once frontage is calculated, the formula for depth is: 

Depth = Area ÷ Frontage 

This approach works well across most lot types, including standard rectangles, corner parcels, and even irregular shapes like wedges or crescents. 

Handling Near-Square Lots 

When a lot is nearly a perfect square, the square root part of the formula can become unstable due to tiny numbers or rounding issues. To avoid this, we’ve added a catch: 

If perimeter² ≤ 16 × area, we treat the lot as a square. 

In those cases, we assume: 

Frontage = Depth = √Area 

This tweak only affects about 4% of lots.