How to import a GeoJSON to change the elevation model

Terrain height related features, such as levees or waterways, may be known in the form of polygons or other types of vector data. It is possible to load in this data so that these features are "carved" (or raised) into (or out of) the existing elevation model. They can be loaded in by loading them in as Terrain. When loading in Terrain, especially when switching between land and water, the elevation model is altered automatically based on the Terrain Type's default Attributes. The defaults can also be overwritten with a custom height and angle to precisely define the height (modifications) desired.

Editor → Current Situation (Ribbon tab) → Terrain (Ribbon bar) → Import geo data (Dropdown)

How to load in terrain height altering features:

1. Prepare a GeoJSON file with polygon features with HEIGHT, ANGLE_OF_REPOSE, and TERRAIN_TYPE Attributes.
2. Open the Geo Data Wizard via the Terrain dropdown.
3. Opt to import a GeoJSON.
4. In the "Assign Terrain type" step, select the default Terrain type to import the data as.
5. If applicable, select "Terrain Type Mapping", and set up a mapping of Attribute values to Terrain types.
6. In the "Adjust heights" step, if applicable, opt to override the height and angle of the terrain, and select the appropriate Attributes.
7. Finalize and close the wizard.
8. The elevation model is now modified with the height changes defined by the GeoJSON file.

Attribute definitions

The following Attributes can be used to prepare a GeoJSON file, with which the elevation model can be altered.

Attribute name	Unit	Description	Default behavior (when attribute is missing)
HEIGHT	m + datum	The water depth (or terrain height) across the polygon.	Height is only changed when changing from land to water or vice-versa. The used height is the height of the terrain added to the relevant WATER_DEPTH_M Attribute of the used terrain.
ANGLE OF REPOSE	angle (0-90°)	The angle, relative to a horizontal plane, at which the feature should be "carved" (or raised) into (or out of) the terrain. If the sides do not meet before the target height is reached, the remainder of the feature will be flat.	The default angle is 90°, so the carving/raising will run vertically until the target height is reached.
TERRAIN_TYPE	nominal value	A value identifying the desired terrain.	All features in the file can only be loaded in as a single type of terrain.

Notes

• The overriding Attributes for the height and angle do not need to be HEIGHT and/or ANGLE, as when they are used they will always need to be selected.
• Undoing this operation may be difficult, if the original terrain heights are not known.
• When using a mapping for Terrain types, features are first checked for a match in the mapping. If none exists, the selected default Terrain type is used.
• The Terrain types listed in the "Assign Terrain type" step's dropdown include both above-ground and underground Terrain types.
• When using the default WATER_DEPTH_M Attribute, the height change is relative to the existing terrain. When using an overriding height Attribute, the height change is relative to datum.