Dutch Portolan Demo

# Human Health Statistics (Gezondheid) -- CBS / Netherlands

## What This Dataset Is

INSPIRE-harmonized health statistics for the Netherlands from **CBS** (Centraal Bureau voor
de Statistiek / Statistics Netherlands). Contains two indicators at the NUTS2 (province)
level:

1. **Doctors per 100,000 inhabitants** (2017 data)
2. **Deaths per 100,000 inhabitants** (2016 data)

This is a **very small dataset**: 12 provinces x 2 indicators = ~24 features total. Each
feature is a provincial boundary polygon with the associated health statistic. It is the
Dutch contribution to the European INSPIRE Human Health and Safety theme.

**Source:** https://www.pdok.nl/introductie/-/article/cbs-gezondheid-human-health-statistics-netherlands-
**Provider:** CBS (Statistics Netherlands)
**License:** CC0 (public domain)

## How to Access

Two GeoParquet files (one per indicator) and a combined PMTiles file for web
visualization are available from Source Cooperative. Native CRS is **EPSG:3035**
(ETRS89-LAEA) — coordinates are in meters.

| File | Features | Size | Contents |
|------|----------|------|----------|
| `doctors.parquet` | 12 | 198 KB | Doctors per 100,000 by province (2017) |
| `deaths.parquet` | 12 | 198 KB | Deaths per 100,000 by province (2016) |
| `gezondheid.pmtiles` | — | 5.0 MB | Both layers as vector tiles |

**Base URL:** `https://data.source.coop/cholmes/portolan-nl/cbs/gezondheid/`

```python
import duckdb

con = duckdb.connect()
con.execute("INSTALL spatial; LOAD spatial;")

URL = 'https://data.source.coop/cholmes/portolan-nl/cbs/gezondheid/doctors.parquet'
df = con.execute(f"SELECT * FROM read_parquet('{URL}')").df()
```

Also available via WFS, WMS, and ATOM from PDOK:
- **WFS:** `https://service.pdok.nl/cbs/hh/wfs/v1_0`
- **WMS:** `https://service.pdok.nl/cbs/hh/wms/v1_0`
- **ATOM:** `https://service.pdok.nl/cbs/hh/atom/v1_0/index.xml`

## Feature Types

| Layer name | Description |
|-----------|-------------|
| `hh:hh-nl-nuts2-doctors-2017` | Doctors per 100,000 inhabitants in 2017, per NUTS2 province |
| `hh:hh-nl-nuts2-death-2016` | Deaths per 100,000 inhabitants in 2016, per NUTS2 province |

Each layer has 12 features (one per province).

## Schema -- Field Meanings

| Field | Type | Meaning |
|-------|------|---------|
| `gml_id` | string | GML feature identifier |
| `localId` | string | Statistical unit ID combining year and NUTS code, e.g. `2016NL11` |
| `namespace` | string | INSPIRE namespace: `NL.KAD.CBS.SU.StatisticalUnit` |
| `identifier` | string | **NUTS2 province code**, e.g. `NL11` (Groningen), `NL33` (Zuid-Holland) |
| `text` | string | **Province name** in Dutch, e.g. `Groningen`, `Noord-Holland` |
| `timePosition` | datetime | Time of the observation |
| `referencePeriod_begin` | datetime | Start of the reference period |
| `referencePeriod_end` | datetime | End of the reference period |
| `areaValue` | float64 | Province area in square metres |
| `HH_NL_NUTS2_doctors_STATCODE` | string | Province code in the doctors layer, e.g. `PV20` |
| `geometry` | MultiPolygon | Provincial boundary in **EPSG:3035** (ETRS89-LAEA) |

Additional INSPIRE-standard metadata fields may be present depending on the WFS response.

## Important Columns

The columns you'll most often use:

- **`identifier`** -- NUTS2 province code (the join key for Eurostat/INSPIRE data)
- **`text`** -- province name in Dutch
- **`geometry`** -- provincial boundary polygon

## NUTS2 Province Codes

| NUTS2 | Province |
|-------|----------|
| NL11 | Groningen |
| NL12 | Friesland |
| NL13 | Drenthe |
| NL21 | Overijssel |
| NL22 | Gelderland |
| NL23 | Flevoland |
| NL31 | Utrecht |
| NL32 | Noord-Holland |
| NL33 | Zuid-Holland |
| NL34 | Zeeland |
| NL41 | Noord-Brabant |
| NL42 | Limburg |

## Geometry Notes

- CRS is **EPSG:3035** (ETRS89-LAEA / European Lambert Azimuthal Equal-Area). This is the
  pan-European standard grid CRS used by INSPIRE, NOT the Dutch national CRS (EPSG:28992).
  Coordinates are in metres on a European-wide grid.
- To convert to WGS84 (lon/lat) for web mapping:
  ```sql
  ST_Transform(geometry, 'EPSG:3035', 'EPSG:4326')
  ```
- To convert to Dutch national CRS:
  ```sql
  ST_Transform(geometry, 'EPSG:3035', 'EPSG:28992')
  ```
- Bounding box in WGS84: [3.37, 50.73, 7.24, 53.55] (all of Netherlands)

## INSPIRE Context

This dataset is part of the INSPIRE (Infrastructure for Spatial Information in Europe)
Directive. INSPIRE harmonizes spatial data across EU member states to enable cross-border
interoperability. The Human Health theme (Annex III) provides health-related statistics
referenced to standard European administrative units (NUTS).

Key implications:
- **NUTS2 level only** -- provincial aggregation, no finer resolution
- **EPSG:3035** -- the mandated INSPIRE CRS for pan-European analysis
- **INSPIRE-standard field names** -- `localId`, `namespace`, `identifier` follow the
  INSPIRE Generic Conceptual Model
- **Designed for European comparison** -- values are rates per 100,000 for cross-country
  comparability

## Useful Query Patterns

### Fetch all doctors data via WFS (Python)

```python
import requests
import geopandas as gpd
from io import BytesIO

url = "https://service.pdok.nl/cbs/hh/wfs/v1_0"
params = {
    "service": "WFS",
    "version": "2.0.0",
    "request": "GetFeature",
    "typeName": "hh:hh-nl-nuts2-doctors-2017",
    "outputFormat": "application/json",
    "srsName": "EPSG:4326"
}
response = requests.get(url, params=params)
gdf = gpd.read_file(BytesIO(response.content))
print(gdf[['identifier', 'text']].to_string())
```

### View on a WMS map (Leaflet/OpenLayers URL)

```
https://service.pdok.nl/cbs/hh/wms/v1_0?service=WMS&request=GetMap&layers=hh-nl-nuts2-doctors-2017&bbox=3.37,50.73,7.24,53.55&width=800&height=600&srs=EPSG:4326&format=image/png
```

## Caveats

- **Data vintage**: Doctor counts are from 2017, death rates from 2016. This is a snapshot,
  not a time series. The data is not regularly updated.
- **Provincial level only**: NUTS2 aggregation means only 12 spatial units per indicator.
  No municipality-level or neighborhood-level breakdown.
- **EPSG:3035 coordinates**: Unlike most Dutch datasets (which use EPSG:28992 RD New), this
  uses the European INSPIRE CRS. You must transform coordinates when combining with other
  Dutch datasets.
- **INSPIRE overhead**: Field names follow INSPIRE conventions, which can be verbose. The
  `namespace` and `localId` fields are INSPIRE administrative metadata, not analytical data.
- **Tiny dataset**: Each parquet file is under 200 KB — small enough to load entirely into
  memory without spatial filtering.


## Visualization Styles

One Mapbox GL v8 style is available for interactive map visualization via the PMTiles file.

Style files are Mapbox GL v8 JSON with relative PMTiles source paths. They can be
used with MapLibre GL JS, OpenLayers (via ol-mapbox-style), or any Mapbox GL v8-compatible renderer.

- **`styles/default.json`** — **Health indicator choropleth.** Red sequential ramp showing doctors-per-province statistics. Light pink (fewer) to deep red (more). Province-level view of healthcare distribution.

Style files are at: `https://data.source.coop/cholmes/portolan-nl/cbs/gezondheid/styles/`
## Also Available As

- **GeoParquet:** `doctors.parquet` (198 KB) and `deaths.parquet` (198 KB), EPSG:3035
- **PMTiles:** `gezondheid.pmtiles` (5.0 MB, for web map visualization)
- **WFS**: Live access via the endpoints listed above
- **WMS**: Map visualization via the WMS endpoints listed above
- **ATOM**: Bulk download via `https://service.pdok.nl/cbs/hh/atom/v1_0/index.xml`