Cognised existence: Surface freshwater bodies are the visible hydrological features of the landscape — rivers, streams, lakes, ponds, reservoirs, and canals. They are both ecological habitats and infrastructure.
Question: What surface freshwater bodies exist at a location and how do they flow?
OSM wiki: https://wiki.openstreetmap.org/wiki/Key:waterway | https://wiki.openstreetmap.org/wiki/Tag:natural%3Dwater
Realisations
Instead of hardcoding implementation schemas here, SPHERE separates semantic meaning from dataset implementation. See the following realisations for how to access this data:
- [[Realisations/OpenStreetMap_freshwater_bodies|OpenStreetMap —
waterway=*,natural=water]] - Natural Earth — Lakes and Rivers
Geometry Representations
| Rep ID | Source Dataset | Geometry Type | Native CRS | Suitable For | Not Suitable For |
|---|---|---|---|---|---|
freshwater_osm_lines | OSM via Geofabrik | LineString | EPSG:4326 | Network tracing, flow direction, river mapping | Catchment area calculation |
freshwater_osm_polygons | OSM via Geofabrik | Polygon | EPSG:4326 | Surface area, shoreline mapping | Flow routing, upstream/downstream analysis |
freshwater_ne_10m_lakes | Natural Earth 10m lakes | Polygon | EPSG:4326 | Global lake context, continental overview | Small or sub-regional lake detail |
freshwater_ne_10m_rivers | Natural Earth 10m rivers and lake centerlines | LineString | EPSG:4326 | Global/continental river context, atlas mapping | Tributary-level hydrological analysis |
Important: For catchment / drainage basin analysis, a DEM-derived hydrological network (e.g. Copernicus DEM + SAGA/WhiteboxTools) is more reliable than OSM waterways.
Limitations
- Small streams are under-mapped in many regions.
- Flow direction is implied by way direction but not always correct.
- For hydrological modelling, supplement with DEM-derived data.