Distance to green areas measures the Euclidean distance (in metres) from every point in the study area to the nearest green area. It provides information on equity of access to green spaces and urban quality from both an ecological and social perspective. Accessible green areas are fundamental for human well-being, reduction of the urban heat island effect, air quality and ecosystem connectivity.
The international ANGSt standard (Accessible Natural Greenspace Standard, Natural England, 2010) defines optimal green access thresholds: within 150 m for proximity areas, 300 m for local parks, 500 m for neighbourhood parks, 1 km for larger natural spaces. The WHO recommends green space access within 300 m of residence for significant health benefits (WHO, 2016).
The indicator calculates the Euclidean distance from every point in the polygon to the nearest green area:
10 — Tree cover (forests and tree coverage)20 — Shrubland30 — Grassland (meadows and pastures)90 — Herbaceous wetland95 — Mangroves100 — Moss and lichenscipy.ndimage.distance_transform_edt to compute Euclidean distance from each pixel to the nearest green classUnit: metres (m)
| Code | Name | Provider | Resolution | Availability |
|---|---|---|---|---|
WRD_ESWCV_99 | ESA WorldCover | ESA / Vito | 10 m | 2020 — 2021 |
WRD_IMPBS_99 | Impact Observatory | Impact Observatory | 10 m | 2017 — present |
WRD_S2SCL_99 | Sentinel-2 SCL | ESA/Copernicus | 20 m | 2017 — present |
WRD_GDYXX_99 | Google Dynamic World | 10 m | continuous | |
WRD_OSMXX_99 | OpenStreetMap | OpenStreetMap Foundation | vector | continuous |
WRD_BIODL_99 | Biodiversa LC | Biodiversa+ | 10 m | 2020 — present |
WRD_CLCBK_99 | CLC Backbone | EEA | 100 m | 2018 |
WRD_CRINE_99 | Corine Land Cover | EEA | 100 m | 1990 — 2018 |
WRD_DOMLT_99 | Dominant Leaf Type | Copernicus Land | 100 m | 2015 — present |
WRD_EUCRP_99 | European Crop Map | JRC | 10 m | 2018 — present |
| Indicator | Unit | Range | Inverted |
|---|---|---|---|
distance_to_green | m | [0, 150, 300, 500, 1000, 2000] | Yes |
Inverted = Yes: for this indicator, a shorter distance is better, as it indicates greater proximity to green areas and better access to nature.
Thresholds follow the ANGSt standard (Natural England, 2010):
| Level | distance_to_green | Interpretation |
|---|---|---|
| E | > 1000 m | Very poor green access — critical urban quality |
| D | 500 – 1000 m | Insufficient green access |
| C | 300 – 500 m | Moderate green access |
| B | 150 – 300 m | Good green access |
| A | 0 – 150 m | Excellent green access — optimal ANGSt standard |
distance_to_green
(m)Calculates the Euclidean distance of each point to the nearest green area, based on ESA WorldCover 2021 (10 m). Green classes: 10 (Tree cover), 20 (Shrubland), 30 (Grassland), 90 (Herbaceous wetland), 95 (Mangroves), 100 (Moss and lichen). Binary mask + scipy.ndimage.distance_transform_edt, conversion to metres. 1000 m buffer for edge effects. ANGSt classification: Excellent (0–150 m), Good (150–300 m), Moderate (300–500 m), Bad (500–1000 m), Very Bad (>1000 m). Inverted indicator: shorter distances are better.