Appendix H QCF Commands

The Quadtree Control File (.qcf) is used to define the grid refinement areas and optionally the model location and extent, it is read into the .tcf using the Quadtree Control File command. For more information on the .qcf see Section 4.2.8. Setting up a quadtree grid is discussed in Section 7.4.1. The available QCF commands are listed below and are detailed in Table H.1.

Base Cell Size
Model Origin and Extent
Orientation Angle
Quadtree Mesh Processing Method
Read GIS Nesting
Spatial Database

Table H.1: TUFLOW HPC QCF Commands

Command	Solver	Description
Base Cell Size ==  [ \(\langle\) cell size\(\rangle\)  | {TGC} ]	HPC Only	Used to set the Level 1 (parent) cell size. If set to “TGC”, then the cell size defined in the .tgc is used. If set to a numerical value, can be used to override the cell size command in the .tgc file. Using metric units (default) the value is in metres. Using Units == US Customary, the value is in feet. See Section 7.4.1 for more details.
Orientation Angle ==  [ \(\langle\) angle \(\rangle\)  | Optimise  |  {TGC} ]	HPC Only	If set to a numerical value (in degrees) defines the model orientation angle and overwrites any angle / location .tgc commands. If Set to “Optimise” the parent Level 1 polygon is used to optimise the angle of the mesh. As such the GIS nesting polygon must have a Level 1 polygon defined. See Section 7.4.1 for more details.
Model Origin and Extent ==  [ {Auto} | TGC ]	HPC Only	If set to “Auto” the extents of the Level 1 GIS polygon are used to define the model origin and extents. If set to “TGC”, the model is located as per the commands in the .tgc file. Note the angle of the model is defined with the Orientation Angle command below. Also note, if set to “Auto” the GIS nesting polygons must have a Level 1 polygon defined, otherwise an ERROR is generated. The default setting is “TGC” if Quadtree Control File == Single Level and “Auto” if a .qcf (e.g. Quadtree Control File == \(\langle\) .qcf\(\rangle\)) is specified. See Section 7.4.1 for more details.
Read GIS Nesting ==  [ \(\langle\) gis file in 2d_qnl format \(\rangle\) ]	HPC Only	Used to define polygons of mesh refinement (different levels). Uses 2d_qnl GIS layers, as described Section 7.4.1.4. See Section 7.4.1 for more details.
Quadtree Mesh Processing Method ==  [ {FAST}  | Memory Efficient  ]	HPC Only	When pre-processing the Quadtree mesh, a hidden 2D domain is used for areas of refinement to allow fast processing of geometry on a regular grid. The default approach, “FAST”, treats each nesting level as a domain, therefore with 3 levels of nesting the geometry control file is processed 3 times. To reduce initialisation memory demands it is possible to treat each GIS polygon in the 2d_qnl as a separate domain for the processing of geometry inputs by setting this command to “Memory Efficient”. Whilst being more memory efficient during mesh creation, this may be slower to initialise. It has no effect on the speed of the hydraulic computations or the memory demand during the hydraulic calculations. See Section 7.4.1 for more details.
Spatial Database ==  [ OFF | TCF ]	HPC Only	Optional when using the GeoPackage input format. Sets the database to use for subsequent inputs. See Section 4.4.3.