DTM

Digital Terrain Model properties

A raster DTM stores height values in a regular grid. The DTM can be exported to the Esri ASCII grid format .asc, that can be then imported into Terrain Builder. Terrain Builder assumes reference coordinates in UTM projection.

The add-on only supports grids with equal resolution in both X and Y directions. Each vertex of a DTM mesh represents a pixel of the exported raster.

Location

The panel is visible for all mesh objects in the Object Data Properties of the Properties editor.

Properties

Cell Size

• Manual: side length of a raster cell is set explicitly

• Calculated: spacing is calculated as the distance between the first two points of the first row, or first column in the raster

Data Type

• Raster: data points are cell centered

• Grid: data points are on cell corners

Easting

X coordinate of the reference origin.

Northing

Y coordinate of the reference origin.

NULL Indicator

Placeholder value for cells where data does not actually exist.

The Null indicator value is technically not used, since the add-on does not support incomplete DTMs, but the parameter is implemented anyway for compatibility purposes.