Table 2

Measures of supermarket access
Mean (s.d.) Median (IQR) Range
Proximity via road network from:
Geometric centroid 1.18 (0.59) 1.06 (0.74–1.57) 0.02–3.78
Population-weighted centroid 1.17 (0.58) 1.06 (0.75–1.56) 0.18–3.25
Postal code 1.16 (0.62) 1.07 (0.70–1.56) 0.02–3.26
Percentage of individuals with a supermarket within:*
0.4 km Euclidean buffer 23.5%
1 km Euclidean buffer 72.7%
2 km Euclidean buffer 100%
0.4 km road network buffer 8.5%
1 km road network buffer 42.8%
2 km road network buffer 87.6%
Count of a supermarket within:*
0.4 km Euclidean buffer 0.29 (0.60) 0 (0–0) 0–5
1 km Euclidean buffer 1.42 (1.45) 1 (0–2) 0–9
2 km Euclidean buffer 5.31 (3.26) 5 (3–7) 1–19
3 km Euclidean buffer 11.53 (5.47) 9 (8–15) 3–26
4 km Euclidean buffer 20.36 (7.74) 18 (14–28) 8–35
5 km Euclidean buffer 29.70 (8.96) 31 (22–37) 12–45
0.4 km road network buffer 0.10 (0.36) 0 (0–0) 0–4
1 km road network buffer 0.70 (1.04) 0 (0–1) 0–7
2 km road network buffer 2.82 (2.82) 2 (1–4) 0–16
3 km road network buffer 6.51 (4.25) 6 (4–8) 0–22
4 km road network buffer 11.79 (6.21) 10 (7–16) 2–28
5 km road network buffer 18.81 (7.98) 17 (12–27) 4–36
Kernel density estimates
0.4 km 0.57 (1.58) 0 (0–0) 0–12.75
1 km 0.48 (0.64) 0.27 (0–0.72) 0–5.00
2 km 0.43 (0.34) 0.38 (0.23–0.52) 0–2.14
3 km 0.43 (0.25) 0.35 (0.28–0.53) 0.09–1.51
4 km 0.42 (0.20) 0.38 (0.28–0.49) 0.12–1.10
5 km 0.41 (0.17) 0.37 (0.27–0.53) 0.14–0.84

*buffers and kernel density estimates based on individual’s postal code locations.

Thornton et al.

Thornton et al. International Journal of Health Geographics 2012 11:29   doi:10.1186/1476-072X-11-29

Open Data