Layout

Ribasim does not use the location of nodes and the geometry of links in the simulation. But a model that follows the real water system is much easier to review, on the map and in the model viewer, so the regional models and the coupled model get a shared layout step. None of this changes the results.

The input model, with straight links.

The final model, with links along the watercourses, and Junctions where they join.

Routing the links

At the end of the forcing stage, ribasim_nl.network_snapping.snap_model aligns the layout of the level controlled models with the hydro-objects in verwerkt/profielen/network.gpkg, which are written by the profile generation:

• Connector nodes stay at the location of the structure they represent.
• Basin nodes are moved onto the nearest main route of the longest connected part of the hydro-objects in their basin, as in the gravity controlled models.
• Links between a Basin and a connector node follow the hydro-objects, complemented by the Top10NL water lines. Hydro-objects are only connected where there is evidence: the culverts (duikersifonhevel) of the crossings data, gaps of at most 2 m, and gaps across BGT water surfaces. Connector nodes far from the hydro-objects are connected over the BGT water surfaces, crossing at most 100 m of land.
• Links stay straight if no such route is found, or if it is not less than ribasim_nl.link_geometries.MAX_STRAIGHT_LINE_RATIO times longer than the straight line, the same threshold as for the gravity controlled models.

In the gravity controlled models, snap_to_waterways routes the links that are still straight along the Top10NL waterways, at the end of their dynamic stage.

Tidying

flowchart LR
  a["Route links"] --> b["junctionify<br>merge shared parts<br>of links"]
  b --> c["tidy_layout"]

ribasim_nl.junctionify merges the shared parts of links into Junctions, and ribasim_nl.layout.tidy_layout makes sure no nodes are on top of each other and no links overlap:

• Bergend Basins are placed 100 m from their doorgaand Basin.
• Links are offset 5 m to the right of their direction, so inflows and outflows along the same waterway are drawn side by side.
• Nodes that are still within 10 m of each other are moved apart.

The gravity controlled models get the same layout step at the end of their dynamic stage, and ribasim_nl.validation.validate_model checks it. The coupling tidies the links between models in the same way, and first rebuilds the routes of the Basins of Rijkswaterstaat along Top10NL.