DHI.Mike1D

Cross section database

The CrossSectionData is a database of ICrossSection's. A cross section is indexed by it location (reach id, chainage) and a topography id (topo-id).

The topography id is used to handle different scenarios. Example: A river was measured in 1980 and again in 2000. Both set of data can be entered into the same cross section database, the first set with a topography id of 1980, the other with the topography id of 2000. Whenever searching for cross sections, the topography id must be provided to specify which data set to use. The topography id can be set on each network reach (IReach) individually, using the TopoID property.

The location of a cross section can be specified in two different ways: By their reach id and chainage, or by their reach id only.

• Reach id and chainage: On a given reach there can be a number of cross sections for different chainages. The bottom level is defined by each cross section individually. This is the traditional MIKE 11 definition.
• Reach id only: On a given reach you can specify one cross section that is valid for the entire reach. The bottom level is extracted from the network geometry - LocationSpan (digipoints). This is the traditional MIKE URBAN definition.

The cross section database can read and write data to and from the MIKE 11 cross section file, .xns11, using the CrossSectionDataFactory.

Cross section API and classes

The ICrossSection does not necessarily know anything about the geometry of the unerlying cross section, whether it is circular, rectangular open or closed; it can be based on tabulated values or formulas. The ICrossSection can have a BaseCrossSection that it delegates its work to. The BaseCrossSection property returns a XsBase

The XsBase is an implementation of the ICrossSection functionality based on processed data. There are a number of specialized derived base cross sections, implementing each their own geometric version of the XsBase.

• XsCircular: A circular cross section with a diameter. This is the circular MIKE 11 cross section
• XsCircularPreprocessed: A circular cross section that can have three different forms: circular, egg-shaped or O-shaped. this is the MIKE URBAN circular cross sections. Processed data can not be modified.
• XsRectangular: A cross section with width and a height. This is the rectangular MIKE 11 cross section
• XsRectangularPreprocessed: A cross section with a widt and a height, and a small depression at the bottom to handle low flow situations. This is the rectangular MIKE URBAN cross section. Processed data can not be modified.
• XsBaseRaw: Cross section with raw data, a set of X-Z cross section points, defining the geometry of the cross section. It comes in two variations: XsOpen, which is the standard open cross section. XsPolygon, a closed cross section, the last cross section point is connected to the first cross section point, thereby closing the cross section.