So sánh phương pháp

	Urban Sprawl Measurement	Compactness Index
Lĩnh vực	Urban Studies	Urban Studies
Họ	Process / pipeline	Process / pipeline
Năm ra đời	2014	2010
Người khởi xướng	Reid Ewing & Shima Hamidi (building on Galster et al.)	Geographic shape-analysis tradition (Richardson, Cole; codified by Angel, Parent & Civco)
Loại	Composite index combining multiple dimensions of urban form into a sprawl/compactness score	Geometric/morphological index of how compact a settlement footprint is
Công trình gốc	Ewing, R., & Hamidi, S. (2015). Compactness versus sprawl: A review of recent evidence from the United States. Journal of Planning Literature, 30(4), 413–432.	Angel, S., Parent, J., & Civco, D. L. (2010). Ten compactness properties of circles: Measuring shape in geography. The Canadian Geographer, 54(4), 441–461.
Tên gọi khác	Sprawl Index, Compactness Index of Sprawl, Ewing Sprawl Index, Composite Sprawl Measure	Shape Compactness Measure, Polsby-Popper Index, Richardson Compactness, Perimeter-Area Compactness
Liên quan	4	4
Tóm tắt	Urban sprawl measurement quantifies how compact or sprawling a metropolitan region is by combining several distinct dimensions of urban form into a single composite index. The dominant approach, developed by Reid Ewing, Shima Hamidi and colleagues, captures four factors — development density, land-use mix, activity centering, and street-network connectivity — and folds standardized indicators of each into one score, calibrated so the average region equals 100 and higher values mean greater compactness. Because sprawl is multidimensional, no single variable such as density adequately describes it, which is why the composite-index strategy has become the standard for comparing regions and linking form to outcomes.	A compactness index measures how compact the shape of a settlement, district, or built-up area is, almost always by comparing it to the circle — the most compact shape enclosing a given area. Classic indices such as the Polsby–Popper or Richardson ratio compare a polygon's area to its perimeter, while more elaborate measures compare interpoint distances or fitted circles, all returning a value of one for a perfect circle and falling toward zero as the shape becomes elongated, indented, or fragmented. Angel, Parent and Civco systematized these into a coherent family by showing that the circle is optimal on ten distinct geometric properties, clarifying which index answers which question.