SMS:TUFLOW 2D Geometry Components

A 2D geometry component groups grids and data that apply to the grid. The other kinds of data in a geometry component include coverages and TIN (scatterset). A TIN is used to modify the Z values. The purpose of each coverage is dependent upon the coverage type. Some coverages will modify z values and others will control other attributes. There can be multiple objects of the same type in a geometry component. When this happens, the data is applied in the order of the objects in the component. This means that the objects below in the project explorer are the ones that will control. This applies to Z as well as other attributes. Links can be rearranged by dragging them up or down within the 2D geometry domain.

Coverages in a geometry component

TUFLOW 2D geometry components associate grids with TUFLOW coverages that apply specifically to the domain. For example a grid component may contain an area property coverage that modifies the materials in the grid. Grids and coverages are represented as TUFLOW Project Explorer links inside of a 2D geometry component. Only one grid or grid frame coverage may be linked in each geometry component.

The following coverages can be put inside of a 2D geometry domain

• Area Property Coverage
• Boundary Condition Coverage
• 2D Z Lines/Polygons (Simple)
• 2D Miscellaneous(Spatial Attributes)
• 2D Z Lines (Advanced)

TINs (scatterset) in a geometry component

• In addition, scatter data can also be put inside a 2D geometry domain to modify Z values. Unlike the other components, it has additional TUFLOW options that can be set in its link's right-click menu. The TUFLOW options that can be set for how the scatter data modifies Z values are "All", "Add", "Min" and "Max".
• Clip Regions for Read Tin z pts. Using a coverage to specify a clip region, makes it so only elevations within coverage polygons are changed by a TIN dragged under a 2D geometry component. This is particularly useful for clipping out a TIN due to unwanted or irregular triangulation around the periphery, especially for secondary TINs of proposed developments lying within the primary TIN.

To use this, create a coverage with one or more polygons. Any coverage type can be used, but it must be a coverage that allows polygons. Only areas within polygons and within the TIN boundaries will have elevations assigned. There must be a scatter set in the 2D Geometry Components. Then drag and drop this coverage under the scatter tree item, under the 2D geometry Components.

After exporting the simulation files, the clip region will be referenced in the line "Read TIN Zpts" in the TGC file.

Considerations for modifying Z data

As mentioned previously, the order links are listed matters for coverages and scatter data. This can be particularly useful for Z data but make certain the attributes are applied in the correct order.

Suppose there is a situation where needing to incorporate a 2.0 m high fenceline and also raise a portion of the domain to model a proposed fill for a development. The fenceline is defined a z-line and the raised domain is a TIN (use a 2D Z Lines/Polygons (simple) coverage if it is a simple fill scenario). If the fenceline is above the TIN in the Project Explorer, anywhere that they overlap the TIN would take precedence and the fenceline would get wiped out. If the fenceline is below the TIN, the TIN elevations will get applied and then the fenceline will raise the elevations 2.0 m above the new elevations. Depending upon the scenario to be represented, either option may be the preferred mechanism.

External files

An external file can be read in as part of a geometry component. As previously mentioned, the order of links is important, and the external file behaves the same way as the z-modifying data. An external file is added by right-clicking on the geometry component and selecting Add External File....

After a file has been selected, a tree item with the file name will appear at the bottom of the geometry component tree item group. This external file item can be moved around to the desired location and the file name can be changed by right-clicking and selecting Browse....

Related Topics

• TUFLOW