Field notes · definitions before conclusions
Read the numbers with their boundaries attached.
Short, sourced explainers on how place data is defined, dated, and compared. Each guide links to the underlying publisher and the relevant profiles, tools, and methods.
Start with a calculation
How population density is calculated
A density figure is a calculation from two inputs. Understanding the population date, area definition, and unit makes the result easier to reproduce and harder to misread.
Read the density guideMethods and place definitions
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Area · definitions and map scale
Land area vs. total area: what is being compared?
An area number is only comparable when its definition is clear. “Land area,” “water area,” and “total area” may represent different accounting choices across datasets.
Population · dates and revisions
Why population data years differ between places
A year printed beside a statistic can mean the period measured, the estimate vintage, or the date a file was released. Keeping those dates separate prevents false precision.
City geography · boundaries before numbers
City proper vs. metro area: why the boundary matters
“City” can name a legal municipality, a statistical place, or a broad commuting region. Comparing their figures without naming the boundary can turn a precise number into a misleading one.