README.md

---
license: cc-by-4.0
pretty_name: EU-Hydro Master Skeleton (curated GeoParquet)
tags:
  - geospatial
  - hydrology
  - europe
  - geoparquet
  - copernicus
---

# EU-Hydro Master Skeleton

Per-basin GeoParquet shards derived from the Copernicus **EU-Hydro v1.3** GeoPackages. Four layers are published — river centerlines, river-surface polygons, inland-water polygons (lakes + wide waters), and river-basin polygons — all reprojected to a common CRS and stripped of admin-only columns for easier querying.

## Contents

```
eu_hydro_master_skeleton_geoparquet/
├── river_lines/        # River_Net_l       MultiLineString  ~1.3 M features
├── river_polygons/     # River_Net_p       MultiPolygon       ~12 k features
├── inland_water/       # InlandWater       MultiPolygon     ~380 k features
├── river_basins/       # RiverBasins       MultiPolygon       ~100 features
└── manifest.csv        # layer, file, source_basin, features
merge_euhydro.py        # reproducer (extract zip → curate → GeoParquet)
```

Each subdirectory holds one shard per basin: `euhydro_<basin>_v013.geoparquet`. Shards are zstd-compressed and carry a `source_basin` column so you can concat them without losing provenance.

### Layer quick reference

| Directory | Source layer | Geometry | Use case |
|---|---|---|---|
| `river_lines/` | `River_Net_l` | MultiLineString | Network topology, Strahler order, routing |
| `river_polygons/` | `River_Net_p` | MultiPolygon | Actual water-surface area of wide rivers — useful for satellite-image overlap (Sentinel-2 NDWI etc.) |
| `inland_water/` | `InlandWater` | MultiPolygon | Lakes, reservoirs, and any water body modelled as an area |
| `river_basins/` | `RiverBasins` | MultiPolygon | Catchment polygons for aggregating per-basin stats |

### Common properties

- **CRS**: `EPSG:3035` (ETRS89 / LAEA Europe) — units are metres, safe for area/length maths without reprojection.
- **Dimensions**: 2D. Original Z/M values from EU-Hydro were dropped.
- **Columns**: admin-only fields (`BEGLIFEVER`, `ENDLIFEVER`, `UPDAT_BY`, `UPDAT_WHEN`) were removed. All other source columns are preserved.
- **Excluded basins**: `fr_guiana`, `fr_islands`, `iceland` — non-continental or overseas.

One note: the `hondo` basin has no `river_polygons/` shard. That's expected — the source GPKG's `River_Net_p` layer is empty for this basin (no rivers wide enough to be captured as an area).

## Quick start

```python
import geopandas as gpd
from huggingface_hub import hf_hub_download

path = hf_hub_download(
    "cassini-team-todo/eu-hydro-master-skeleton",
    "eu_hydro_master_skeleton_geoparquet/river_polygons/euhydro_shannon_v013.geoparquet",
    repo_type="dataset",
)
shannon_polys = gpd.read_parquet(path)
print(shannon_polys.crs, shannon_polys.geom_type.unique(), len(shannon_polys))
```

Loading a whole layer across all basins:

```python
from pathlib import Path
import geopandas as gpd, pandas as pd
from huggingface_hub import snapshot_download

local_root = Path(snapshot_download(
    "cassini-team-todo/eu-hydro-master-skeleton",
    repo_type="dataset",
    allow_patterns="eu_hydro_master_skeleton_geoparquet/inland_water/*.geoparquet",
))
shards = sorted((local_root / "eu_hydro_master_skeleton_geoparquet" / "inland_water").glob("*.geoparquet"))
inland_eu = pd.concat([gpd.read_parquet(p) for p in shards], ignore_index=True)
```

## Reproducing

The source GeoPackages aren't redistributable through this repo — download them from the Copernicus Land portal (EU-Hydro v1.3, per-basin GPKG zips). Place all `euhydro_*_v013_GPKG.zip` files in the same directory as `merge_euhydro.py` and run:

```bash
python merge_euhydro.py
```

This will extract each zip to a temp dir, read the four target layers with `force_2d=True`, drop admin columns, reproject any basin whose CRS differs from the first valid one, and write the output tree next to the script. A `manifest.csv` summarizing every shard is written at the end.

## Source and licensing

- **Source**: Copernicus EU-Hydro v1.3 — https://land.copernicus.eu/en/products/eu-hydro
- **License**: Copernicus data is free and open (attribution required). This derived dataset is released under CC-BY-4.0; please cite Copernicus EU-Hydro in any downstream use.