Data Connectors · Environment

LANUK Flood Portal

The node downloads the ZIP file with the current water levels of the NRW flood portal (operated by the State Agency for Nature, Environment and Climate, LANUK), extracts the contained CSV file and joins it with the station list. The result is a set of FloodMonitoring entities according to the FIWARE Smart Data Model, either with the latest value or the full time series.

Data source
Trigger or polling
FloodMonitoring

Node type: lanuk
Package: @htag/node-red-contrib-hypertegrity-environment
Inputs / outputs: 1 / 1
Data source: NRW flood portal (hochwasserportal.nrw)

When to use this node

The NRW flood portal publishes the water levels of the state gauges in North Rhine-Westphalia as a regularly updated archive. The LANUK node brings this archive into a Node-RED flow, assigns the gauge master data to every reading and maps everything to the Smart Data Model FloodMonitoring, including danger threshold and flood status.

Typical use cases are:

Gauges on state waters such as Ruhr, Lippe, Sieg or Wupper transferred into an NGSI-LD context broker.
Flood alerting flows that evaluate the status Danger and trigger notifications.
Time series of a gauge provided for dashboards or analyses.

How the node works

Trigger

An incoming message or the poll timer starts the fetch. If a fetch is already running, the new one is skipped.

Download

Station list (JSON) and measurement archive (ZIP with CSV) are loaded in parallel; the CSV is extracted.

Join

Readings are grouped by station number, sorted and enriched with name, catchment, coordinates and thresholds of the station.

Emit

One FloodMonitoring entity is built per station, emitted as one array or as one message per station.

Result: FloodMonitoring entities with current water level in centimetres, status, location and retrieval metadata in msg.lanuk.

The node works trigger-based or by polling. With a poll interval of 0 only an incoming message starts the fetch. With an interval greater than 0 the node also fetches on its own and, if enabled, once about 2 seconds after startup. Properties of the triggering message are carried over into the output.

Configuration

The edit dialog is divided into the tabs General, Stations, Sources and Advanced.

General tab

Field	Type	Default	Meaning
Name	Text	empty	Display name of the node in the flow. Without a name the node shows "LANUK Hochwasser".
Output mode	Select (`latest`, `timeseries`)	`latest`	Latest value only emits the most recent reading per station; Full time series adds an array `measurements` with all values of the archive to each entity.
Message format	Select (`array`, `split`)	`array`	Single message (array) sends all entities in one message; One message per station sends a separate message per entity.

Stations tab

Field	Type	Default	Meaning
Show only stations with current measurements	Checkbox (dialog only)	enabled	Shows only stations that have readings in the current archive in the left-hand list. If the archive is unreachable, all stations are shown.
Available stations / Selected stations	Dual list with search field	no selection	Use the arrow buttons to move stations to the right-hand list. The station numbers are stored in the array `stations`. Without a selection the node emits all stations that have readings.
Reload / Clear selection	Buttons	–	Reloads the station list, or removes the whole selection.

Sources tab

Field	Type	Default	Meaning
Measurements ZIP	Text (required)	see below	Address of the measurement archive. The contained text file is a semicolon-separated CSV with the columns `station_no`, `time`, `value`.
Station list	Text (required)	see below	Address of the station master data.
Poll interval (min)	Number	`0`	Fetch interval in minutes. `0` disables polling; then only an input message starts the fetch.
Fetch on startup	Checkbox	enabled	With polling enabled, performs a first fetch about 2 seconds after deployment.
Timeout (sec)	Number	`60`	Timeout for the two downloads in seconds.

Default values of the URL fields:

Measurements ZIP: https://www.hochwasserportal.nrw/data/downloads/messwerte.zip
Station list:     https://www.hochwasserportal.nrw/data/internet/stations/stations.json

Advanced tab

Field	Type	Default	Meaning
Entity type	Text (required)	`FloodMonitoring`	Value of the field `type` in every entity and of `msg.topic` in array mode.
ID prefix	Text	`urn:ngsi-ld:FloodMonitoring:LANUK:`	Prefix of the entity ID. The ID is built from prefix and station number.
Debug mode	Checkbox	off	Writes detailed logs as warnings to the debug sidebar.

Input

Every incoming message triggers a fetch. The node does not evaluate any special properties but passes the message on as the base of the output.

Property	Type	Meaning
`msg`	any	Starts the fetch. All properties of the message are kept in the output; `payload`, `topic` and `lanuk` are overwritten.

If a message arrives while a fetch is running, it is skipped (with a hint in debug mode).

Output

In the message format array the node sends one message with all entities; in the format per station one message per entity with msg.topic set to the entity ID. In both cases msg.lanuk contains metadata about the retrieval.

{
  "payload": [
    {
      "id": "urn:ngsi-ld:FloodMonitoring:LANUK:2718130000100",
      "type": "FloodMonitoring",
      "stationID": "2718130000100",
      "currentLevel": 84,
      "observationDateTime": "2026-10-01T08:00:00+02:00",
      "name": "Exampletown",
      "areaServed": "Example Brook",
      "dataProvider": "LANUK",
      "location": {"type": "Point", "coordinates": [7.0101, 51.4502]},
      "dangerLevel": 180,
      "referenceLevel": 112.5,
      "floodLevelStatus": "Normal",
      "source": "https://www.hochwasserportal.nrw/data/internet/stations/stations.json",
      "unitCode": "CMT"
    }
  ],
  "topic": "FloodMonitoring",
  "lanuk": {
    "dataModel": "FloodMonitoring",
    "source": "LANUK Hochwasserportal NRW",
    "zipUrl": "https://www.hochwasserportal.nrw/data/downloads/messwerte.zip",
    "stationsUrl": "https://www.hochwasserportal.nrw/data/internet/stations/stations.json",
    "outputMode": "latest",
    "retrievedAt": "2026-10-01T08:15:00.000Z",
    "stationCount": 1,
    "unmatchedStations": 0,
    "containsPersonalData": false
  }
}

Field	Meaning
`id`	ID prefix followed by the station number.
`type`	Configured entity type, `FloodMonitoring` by default.
`stationID`	Station number (`station_no`) from the archive.
`currentLevel`	Latest water level of the station in centimetres.
`observationDateTime`	Timestamp of the latest reading, unchanged from the CSV column `time`.
`name`	Station name from the master data; missing if the station is not in the station list.
`areaServed`	Catchment (`catchment_name`) from the master data.
`dataProvider`	Operator according to the master data (`LANUV_Betr`, falling back to `site_name`); `LANUK` without master data.
`location`	GeoJSON point in the order longitude, latitude; only present if the master data provides coordinates.
`dangerLevel`	Mean flood level (MHW) in centimetres from the master data; omitted if missing or `0`.
`referenceLevel`	Gauge datum (`station_gauge_datum`) in centimetres; omitted if missing or `0`.
`floodLevelStatus`	`Danger` if `currentLevel` reaches or exceeds the danger threshold, otherwise `Normal`. Omitted without `dangerLevel`.
`source`	Configured address of the station list.
`unitCode`	Always `CMT` (UN/CEFACT code for centimetre).
`measurements`	Only in full time series mode: array of objects with `observedAt` and `currentLevel`, sorted chronologically.
`lanuk.stationCount`	Number of emitted entities.
`lanuk.unmatchedStations`	Number of stations with readings but without an entry in the station list.
`lanuk.containsPersonalData`	Always `false`; the data contains no personal information.

Example flow

The package ships with an example flow. Import it in Node-RED via Menu → Import → Examples → @htag/node-red-contrib-hypertegrity-environment → lanuk. Alternatively download lanuk.json and import it via Menu → Import.

Step 1

Inject

An Inject node 'Go!' triggers the fetch manually. Alternatively set a poll interval in the node.

Step 2