Table 1.
Food and drink categories extracted from the Tesco Grocery 1.0 dataset [41].
Fig 1.
Map of our study area with LSOA boundaries included.
The area of focus is highlighted in green. Shapefiles for LSOA boundaries were obtained from the Greater London Authority via the London Datastore [63]: https://data.london.gov.uk/dataset/statistical-gis-boundary-files-london. Contains National Statistics data Crown copyright and database right 2015. Contains Ordnance Survey data Crown copyright and database right 2015. Licensed under the UK Open Government Licence v2.0 (https://www.nationalarchives.gov.uk/doc/open-government-licence/version/2/).
Fig 2.
Principal component 1 loadings as defined in Sect 2.2 against their respective food categories.
Sweets, fruit and vegetables, fish, grains, and soft drinks have the highest positive loadings. Purchases of sweets, grains and soft drinks are inversely correlated with purchases of fruit and vegetables and fish.
Fig 3.
Principal component scores across our study area.
Adherence to purchases high in sugar and carbohydrates are most prevalent in London’s east, west and north-west (red). Adherence to high-fibre and high-protein purchases are predominantly in London’s inner-west (blue). Shapefiles for LSOA boundaries were obtained from the Greater London Authority via the London Datastore: https://data.london.gov.uk/dataset/statistical-gis-boundary-files-london. Contains National Statistics data Crown copyright and database right 2015. Contains Ordnance Survey data Crown copyright and database right 2015. Licensed under the UK Open Government Licence v2.0 (https://www.nationalarchives.gov.uk/doc/open-government-licence/version/2/).
Fig 4.
Local Indicators of Spatial Association (LISA) clusters of PC1 score at the 95% significance level.
Hot Spots (red) represent areas where purchases are nutritionally deficient, and are our indicator of ‘food deserts’. Cold Spots (blue) represent areas that have purchasing habits reflecting that of a ‘food oasis’. Shapefiles for LSOA boundaries were obtained from the Greater London Authority via the London Datastore: https://data.london.gov.uk/dataset/statistical-gis-boundary-files-london. Contains National Statistics data Crown copyright and database right 2015. Contains Ordnance Survey data Crown copyright and database right 2015. Licensed under the UK Open Government Licence v2.0 (https://www.nationalarchives.gov.uk/doc/open-government-licence/version/2/).
Table 2.
Summary statistics for our response variable, PC1, and LSOA-level sociodemographic data across our study area.
BAME refers to Black, Asian, and minority ethnic population (%). Data is collected alongside the Tesco Grocery 1.0 data, London Datastore (summarised data from the 2011 Census at LSOA level), and the Department for Transport (DfT).
Table 3.
OLS regression estimates and associated p-values.
Fig 5.
Map of neighbourhood (bandwidth) size, b = 72 nearest LSOAs.
The black LSOA is the target LSOA, and the red LSOAs are considered its neighbours. The chosen bandwidth appears approximately valid for resolving geographical features of the scale of the food deserts visible in Figs 3 and 4. Shapefiles for LSOA boundaries were obtained from the Greater London Authority via the London Datastore: https://data.london.gov.uk/dataset/statistical-gis-boundary-files-london. Contains National Statistics data Crown copyright and database right 2015. Contains Ordnance Survey data Crown copyright and database right 2015. Licensed under the UK Open Government Licence v2.0 (https://www.nationalarchives.gov.uk/doc/open-government-licence/version/2/).
Table 4.
Performance of the different spatial weighting functions and bandwidth selection schemes.
We opt to use a bi-square kernel with bandwidth of 72, which minimises the AICc of the resulting model.
Fig 6.
Map of local R2 for our GWR model.
Darker areas correspond with a better model fit, and LSOAs classified as food deserts according to LISA clusters are outlined in white. Shapefiles for LSOA boundaries were obtained from the Greater London Authority via the London Datastore: https://data.london.gov.uk/dataset/statistical-gis-boundary-files-london. Contains National Statistics data Crown copyright and database right 2015. Contains Ordnance Survey data Crown copyright and database right 2015. Licensed under the UK Open Government Licence v2.0 (https://www.nationalarchives.gov.uk/doc/open-government-licence/version/2/).
Fig 7.
Sociodemographic estimates (left column) and corresponding GWR model contributions Cik (right column) mapped across London for (a–b) household median income, (c–d) car ownership, (e–f) Black, Asian, and Minority Ethnic population, and (g–h) average age.
LSOAs outlined in black denote areas where the LISA cluster is a Hot Spot (food purchases are reflective of ‘food deserts’), and the coefficient for location i and covariate k is statistically significant. Household income; Black, Asian, and minority ethnic population; and car ownership contribute to nutrient deficient purchases in food desert areas. Shapefiles for LSOA boundaries were obtained from the Greater London Authority via the London Datastore: https://data.london.gov.uk/dataset/statistical-gis-boundary-files-london. Contains National Statistics data Crown copyright and database right 2015. Contains Ordnance Survey data Crown copyright and database right 2015. Licensed under the UK Open Government Licence v2.0 (https://www.nationalarchives.gov.uk/doc/open-government-licence/version/2/).
Fig 8.
Map of Most Influential Predictor (MIP) in food deserts: variables that have the largest contribution to nutrient deficient purchasing behaviour.
Opaque polygons represent food desert areas. ‘Insignificant’ areas refer to LSOAs where there are only negative contributions (contributions toward healthy behaviour), or, areas where there is not a statistically significant coefficient. BAME refers to Black, Asian, and minority ethnic population (%). Shapefiles for LSOA boundaries were obtained from the Greater London Authority via the London Datastore: https://data.london.gov.uk/dataset/statistical-gis-boundary-files-london. Contains National Statistics data Crown copyright and database right 2015. Contains Ordnance Survey data Crown copyright and database right 2015. Licensed under the UK Open Government Licence v2.0 (https://www.nationalarchives.gov.uk/doc/open-government-licence/version/2/).