The Distances KPI analyses the proximity of the site to key geographic features and infrastructure within a 10 km radius. Unlike most indicators on the platform, Distances does not return a scalar A–E score: it provides a structured list of geographic elements with their distances expressed in kilometres, grouped by distance band and type.
Elements are categorised by type:
Connectivity between ecosystems and water resources is a critical factor for biodiversity (Pringle, 2003). Proximity to watercourses influences water availability, riparian species composition, and overall habitat quality. Distance from inhabited centres provides context on the anthropogenic pressure on the site.
This KPI is closely related to Green Equity, which measures the distance from urban green areas for the population in the analysed area, with an inverted A–E quality scale.
Distances are calculated from the polygon edge (not the centroid) to geographic features within 10 km, ensuring geometric accuracy for sites of any size.
where D = minimum edge-to-edge distance (m), R = ROI polygon, F = feature polygon, computed in UTM coordinates
Polygon coordinates are projected into the local UTM zone for accurate metric calculations. Geographic features are queried from OpenStreetMap (Overpass API) for lakes, rivers, canals, and inhabited centres, and from Marine Regions (VLIZ) for sea distance. Features are classified as natural or artificial watercourses and grouped into distance bands: 0–1 km, 1–3 km, 3–5 km, 5–10 km.
Distribution Table. A table listing all geographic features and inhabited centres within 10 km of the site, grouped by distance band and type.
Purpose: Which water bodies, seas, and inhabited centres are located near the site, and at what distance?
Description: The table presents columns: Distance (band: 0–1 km, 1–3 km, 3–5 km, 5–10 km), Lakes, Natural watercourses, Artificial channels, Seas, Inhabited centres. Each cell contains the names of geographic features present in that distance band for that type, or is empty if no feature falls in that combination. The section is available on the Assessment page under the "Land use" tab.
How it's calculated: For each geographic feature within 10 km, the minimum edge-to-edge distance in UTM coordinates determines the distance band. Features are classified by type using OpenStreetMap tags (natural vs artificial watercourses) and the Marine Regions dataset for seas.
Interpretation example:
If the table shows "Lakes: Lake Como" in the 3–5 km band, it means the site edge lies 3–5 km from the shore of Lake Como — relevant for assessing the site's hydrological connectivity and potential impacts on the lake ecosystem.
Ring Gauge. A circular comparison chart (site vs control) showing the percentage distribution of distances from green areas for the population in the analysed area, with an A–E quality grade and site-control delta.
Purpose: How equitable is access to green spaces for the population in the site area compared to the surrounding control area?
Description: The component displays two rings side by side — one for the Site (ROI) and one for the Control (CA) — each divided into segments proportional to the distance bands to the nearest green areas. A quality grade badge (A–E) indicates overall site quality, and a delta value (Site minus Control) shows the difference. The unit of measurement is metres (m).
81mGreen Equity
How it's calculated: The population-weighted average distance to the nearest green space in the analysed area determines the grade. Distance bands are: < 150 m, 150–300 m, 300–500 m, 500–1,000 m, > 1,000 m. The grade is assigned using the ANGSt classification (Natural England 2010).
Note: This indicator is inverted — lower values indicate better conditions (the population is closer to green spaces).
Legend:
| Level | Distance | Color | Meaning |
|---|---|---|---|
| A | 0–150 m | ■ #006400 | Very Close — excellent access to green spaces |
| B | 150–300 m | ■ #32CD32 | Close — good accessibility |
| C | 300–500 m | ■ #FFFF00 | Moderate — acceptable accessibility |
| D | 500–1,000 m | ■ #FFA500 | Far — limited access to green spaces |
| E | > 1,000 m | ■ #FF0000 | Very Far — strong inequality in green space access |
Interpretation example:
If the Site ring shows grade A with a mean distance of 81 m and the Control shows grade A with 57.6 m, the population in the site area has excellent access to green spaces — nearly all residents live within 150 m of a green area — in line with ANGSt guidelines.
Ring Gauge. A sub-chart within the Green Equity panel showing the distribution of population distances to the nearest green area (any type, no minimum patch size), with a site-control comparison.
Purpose: How far is the population in the analysed area from the nearest green space, regardless of size?
Description: Two side-by-side rings (Site vs Control) showing the percentage distribution across distance bands < 150 m, 150–300 m, 300–500 m, 500–1,000 m, > 1,000 m.
81mDistance to Green Areas
How it's calculated: The distance raster is computed by applying a Euclidean distance transform to a green mask derived from ESA WorldCover 2021 (vegetation classes: trees, shrubs, grass, wetlands, mangroves, moss/lichen). Each pixel's distance to the nearest green cell is converted to metres based on the native resolution (10 m). No minimum patch size filter is applied.
Note: This indicator is inverted — lower values indicate better conditions.
Legend: See the Green Equity table above (same ANGSt classification).
Interpretation example:
If the ring shows 100% of the population within 150 m of a green area, the site is completely surrounded by vegetation — an excellent condition for urban environmental quality.
Ring Gauge. A sub-chart within the Green Equity panel showing the distance from the population to the nearest green patch of at least 0.04 ha (pocket parks, community gardens).
Purpose: How far are residents in the analysed area from the nearest small green space (at least 400 m squared)?
Description: Two side-by-side rings (Site vs Control) with the same distance bands.
93mDistance to Small Gardens
How it's calculated: Identical to "Distance to Green Areas" with an additional patch filter: green patches smaller than 0.04 ha (approximately 40 pixels at 10 m) are removed before computing the distance transform.
Note: This indicator is inverted — lower values indicate better conditions.
Legend: See the Green Equity table (same ANGSt classification and distance bands).
Interpretation example:
If this ring shows a mean distance of 93 m with grade A, nearly all the population lives within 93 m of a public garden or green area of at least 400 m squared — an excellent green equity score for local proximity.
Ring Gauge. A sub-chart within the Green Equity panel showing the distance from the population to the nearest public park of at least 0.5 ha (ANGSt neighbourhood park standard).
Purpose: How far are residents from the nearest significant public park (at least 5,000 m squared)?
Description: Two side-by-side rings (Site vs Control) with the same distance bands.
500mDistance to Parks
How it's calculated: Identical to "Distance to Small Gardens" with a higher patch threshold: green patches smaller than 0.5 ha (approximately 500 pixels at 10 m) are removed.
Note: This indicator is inverted — lower values indicate better conditions.
Legend: See the Green Equity table (same ANGSt classification).
Interpretation example:
If this ring shows grade E with a mean distance over 1,000 m, residents in the analysed area have no significant public parks nearby — a signal of strong inequality in access to recreational green spaces.
Assessment Sidebar Row. A row in the left-hand assessment sidebar panel showing the quality grade and site/control values for distance to green areas.
Purpose: How does the site's distance to green areas compare to the control area, in a compact sidebar summary?
Description: The row displays the label "Distance to Green Areas" with the quality grade, Site value (e.g. 81.0 m), Control value (e.g. 57.6 m), and the site-control difference.
How it's calculated: The grade shown in the sidebar uses the same ANGSt classification applied to the site's mean distance.
Note: This indicator is inverted — lower values indicate better conditions.
Interpretation example:
If the sidebar shows Site: 81.0 m / Control: 57.6 m, the site has slightly less immediate access to green areas than the surrounding territory, but both fall within the A band (< 150 m).
Assessment Sidebar Row. A row in the assessment sidebar showing the grade and values for distance to small gardens.
Purpose: Compact summary of distance to small gardens (at least 0.04 ha) in the assessment sidebar.
Description: Row labelled "Distance to Small Gardens" with quality grade, Site value and Control value in metres.
How it's calculated: Same as "Distance to Green Areas" with a minimum 0.04 ha patch filter.
Note: This indicator is inverted — lower values indicate better conditions.
Interpretation example:
If the sidebar shows Site: 93 m / Control: 155 m, the site is closer to small gardens than the control area — a local green accessibility strength.
Assessment Sidebar Row. A row in the assessment sidebar showing the grade and values for distance to parks (at least 0.5 ha).
Purpose: Compact summary of distance to significant parks in the assessment sidebar.
Description: Row labelled "Distance to Parks" with quality grade, Site value and Control value in metres.
How it's calculated: Same as "Distance to Green Areas" with a minimum 0.5 ha patch filter.
Note: This indicator is inverted — lower values indicate better conditions.
Interpretation example:
If the sidebar shows Site: 2,000 m / Control: 2,000 m, both the site and the control area are far from significant parks — both grade E (> 1,000 m).
Slider Card. A scrollable card in the available maps panel (Maps > Land use) showing a thumbnail preview of the distance-to-green raster layer with its last update timestamp.
Purpose: Provide quick access to the distance-to-green map layer and indicate when it was last updated.
Description: The card shows a thumbnail image of the distance raster, the name "Distance to green areas," and the last update date. Clicking the card loads the interactive layer on the map. Equivalent cards exist for "Distance to small gardens" and "Distance to parks."
How it's calculated: The displayed raster is the output of the distance-to-green computation (ESA WorldCover 2021, 10 m), coloured with a continuous colormap from dark green (0 m) to red (at least 1,000 m).
Note: This indicator is inverted — areas shown in dark green are closest to green spaces (best conditions).
Interpretation example:
If the card thumbnail appears almost entirely dark green, the site is fully surrounded by vegetation and the maximum distance to a green area is under 150 m — grade A conditions.
Map Layer. An interactive cartographic overlay showing the spatial distribution of distances to green areas in the analysed area, selectable from the layer dropdown on the Maps page.
Purpose: Where is access to green spaces most limited within and around the site perimeter?
Description: The layer displays a raster where each pixel is coloured according to its distance to the nearest green area: dark green for the closest zones, light yellow for the most distant. The dropdown also includes "Distance to small gardens" and "Distance to parks" layers.
How it's calculated: The layer is the ESA WorldCover 2021 distance raster at 10 m resolution, coloured with a continuous 5-stop colormap.
Note: This indicator is inverted — darker green areas indicate better conditions.
Legend:
| Distance | Color | Meaning |
|---|---|---|
| 0–150 m | ■ #006400 | Excellent accessibility (grade A) |
| 150–300 m | ■ #32CD32 | Good accessibility (grade B) |
| 300–500 m | ■ #FFFF00 | Moderate accessibility (grade C) |
| 500–1,000 m | ■ #FFA500 | Limited accessibility (grade D) |
| > 1,000 m | ■ #FF0000 | Very limited access (grade E) |
Interpretation example:
If the map shows an area almost entirely in dark green with small yellow patches corresponding to paved roads or car parks, the site and its surroundings have excellent access to green spaces, with only isolated zones of lower quality.
| Source | Provider | Coverage | Resolution | Period |
|---|---|---|---|---|
| OpenStreetMap (Overpass API) | OpenStreetMap Foundation | Global | Vector | Continuous (collaborative updates) |
| Marine Regions | VLIZ (Flanders Marine Institute) | Global | Geospatial database | Continuous |
| ESA WorldCover 2021 | European Space Agency | Global | 10 m | 2021 |
Distances are calculated from the polygon edge to geographic features within 10 km using the following processing pipeline:
The Green Equity sub-indicators are computed separately on ESA WorldCover 2021 rasters at 10 m resolution. A Euclidean distance transform is applied to a green mask (vegetation classes: trees, shrubs, grass, wetlands, mangroves, moss/lichen). The three levels differ only by minimum patch size: none (Distance to Green Areas), at least 0.04 ha (Distance to Small Gardens), at least 0.5 ha (Distance to Parks).
The computation is performed asynchronously: the first request triggers a dedicated background worker; subsequent requests are served from cache.