Workspaces let you change the terrain model and observe the effects on flood risk analysis. You access the edit tool through the following steps:
This brings up a range of different tools for editing the terrain:
Interpolates linearly between the terrain elevation at the first and last point of the path.
Usage example: Cut through obstructions in the terrain, build bridges.
Interpolates linearly between the terrain elevation at the first and last point of the path, raising the path by a set height.
Usage example: Raise a wall that follows the terrain uphill or downhill.
Interpolates linearly between the elevations of the first and last point of the path, lowering the path by a set height.
Usage example: Create a ditch or culvert that follows the terrain uphill or downhill.
This tool supports a path as well as an area mode. The path mode creates a flat wall raised by a set height over the highest elevation of any of the vertices of the path. The area mode raises an area delineated by a polygon relative to the highest value along the boundary of the entire polygon.
Usage example: Create a flat dam or wall. In the area mode this can be used to create building outlines.
This tool supports a path as well as an area mode. The path mode creates a flat path, lowered by a set height relative to the minimum elevation of any of the vertices of the path. The area mode lowers an area delineated by a polygon relative to the lowest elevation value along the entire boundary of the polygon.
Usage example: Create a flat culvert. In the area mode this can be used to create drainage basins.
Creates a subsurface structure between the two end points of the path. The edit does not change any elevation on the terrain, but it allows water to be transported between the end points without affecting the terrain between them. The subsurface structure will transport an unlimited amount of water, but it does not store any water itself – it has zero volume.
Usage example: Model culverts and underpasses without obstructing flow over the top of the structure.
Creates a sink point on the surface connected to a subsurface basin with a specified volume. This volume can either be typed in manually or set to an event-specific runoff volume from the watershed of the sink point. This runoff volume is determined by first clicking the "Query Runoff" button next to the volume input field and then selecting the sink point position on the map. The event determining the run-off volume can be varied by dragging the rain slider which appears when clicking the "Query Runoff" button.
Usage example: Model the effect of a subsurface basin or a sewage drain with a guaranteed service level (e.g. a sewage drain dimensioned to handle the runoff volume for a 15 mm rain event).
The select tool lets you select any of the features (paths and areas) in the workspace, once selected the position of any vertex of a feature can be changed interactively by dragging the vertex. New vertices can also easily be created by clicking anywhere on the feature. You can fine-tune the elevation of the vertices using the profile tool that is available through the selection dialog. For area features, the selection dialog will also display the volume of the raised part of the terrain.
The video below demonstrates the creation, editing and deletion of workspaces.
Demonstration of the workspace creation, editing and deletion.