The following is a list of common terms you'll encounter when working with simulation.
| Term | Description |
|---|---|
Simulation layer | The resultant layer added to the Contents pane after defining the area of interest. |
Area of interest | The defined area in which the simulation will run. |
Cell size | An area of interest is evenly divided into cells prior to calculating the simulation result. The size of the cell is directly proportional to the size of the area of interest and, by default, is automatically calculated. For example, an 8 kilometer by 8 kilometer extent uses a 2.0 meter cell size. You can choose to override this value for a layer by disabling the Maximum Fit button Tip:To use a cell size that matches the elevation DEM resolution, you must provide a cell size that is larger than the automatically calculated cell size. |
A point location in the scene where water is introduced into the simulation. | |
A polygon in the scene where water is introduced into the simulation at a specified flow rate. | |
Drainage | A collection of channels that have been defined for a simulation. |
A two-point linear feature that permits water to flow under the elevation surface, such as out of a dam or through a stream blockage caused by an overpass captured in the surface. | |
A linear feature that blocks the normal flow through ridges in the elevation surface. | |
A polygon in the scene where water is removed from the simulation at a specified flow rate. | |
Rainfall rate | The amount of rain that would fall over a given interval of time if the rainfall intensity were constant over that time period. |
Transition time | The time to be used changing between two rainfall rates. |
Infiltration rate | The rate soil can absorb water. |
Maximum infiltration | The maximum allowable infiltration rate. Once reached, water is no longer able to be absorbed and instead continues to move downhill. |
Surface roughness | The level of roughness of the surface. This value impacts the maximum water flow speed and is based on Manning's roughness coefficient, also known as Manning's n, a coefficient that represents the roughness, or friction, that is applied to water flow when estimating water speed. Example values are included in the Surface Roughness Value drop-down gallery. Dive-in:Manning's roughness coefficient is a way to estimate the impact of the surface on the average velocity of water in an open channel. Robert Manning compiled the formula by comparing and evaluating the best known formulas of the time and presented it in a paper titled On the Flow of Water in Open Channels and Pipes, which was published in 1891 (Transactions of the Institution of Civil Engineers of Ireland, p.173). This formula remains to this day the standard for calculating the impact that surface roughness has on the flow of water. |
Maximum resolution | The maximum processing resolution for capturing the elevation values and calculating the movement of water for a simulation layer. Three processing resolutions are available:
The default value for a new simulation layer is
defined in the Simulation Cache section of the Map and Scene tab
of the project Options dialog box. You can override it for a simulation layer by disabling the Maximum Fit button |
Temporal resolution | The number of computations done per simulation second. Three temporal resolutions are available:
|
Playback frame rate | The maximum frames per second (fps) used to display the in-progress simulation calculations in the view. Higher frame rates look smoother but can increase the total time needed to complete the calculations. Use a low frame rate to minimize processing time. Available rates are as follows:
|
and then typing a new value.