A Terrain with Imagery data set is optimised for high performance loading and rendering of large scale, high detail terrain data. It features several levels of detail that dynamically load and unload based on the terrains distance from users position. At the highest detail level, a Terrain can be represented as a Digital Elevation Model (DEM) or Triangulated Irregular Network (TIN).
A regular large scale terrain dataset may be comprised of hundreds of GB of DEM or TIN data plus imagery. This is not suitable for fast loading across LAN or Internet connections. It will not achieve high performance due to large quantities of data to render.
The Urban Engine model conversion pipeline can convert this data into a structure and format suitable for web streaming and high performance rendering.
- Available Resolutions
- TIN with 10cm Imagery (Maximum – lidar source data only)
- 1m DEM with 10cm Imagery (Maximum – DEM only)
- 2m DEM with 20cm Imagery
- 4m DEM with 40cm Imagery
- 8m DEM with 80cm Imagery
- 16m DEM with 160cm Imagery
- Maximum Size: Unlimited
DEM vs TIN
A DEM represents terrain as height samples arranged in a grid structure with set spacing between. Depending on the process used to create the DEM, each height sample may be exact or an average of source data. The Urban Engine supports a maximum 1M DEM resolution. For higher resolution terrain, consider using a TIN format.
A TIN represents terrain as a 3D mesh. The model conversion pipeline creates TIN’s from ground classified lidar, ensuring each vertex in the created mesh corresponds to a lidar sample point, giving maximum accuracy. The number of Lidar sample points is technically unlimited, however for best performance it is recommended to keep the number of samples below 32ppm.
Both DEM and TIN data sets use lower detail DEM’s for each level of of detail below maximum. These lower detail levels are created by downsampling the highest detail level, and may contain approximationsof height data.
Supported Data Formats and Types
Terrain with Imagery can be created using our model conversion pipeline from the following formats. Note: All data sets must be geo-located in the same coordinate system as your model. If your data differs from the below requirements, contact Urban Circus
Terrain DEM
- Type: Digital Elevation Model (ground surface)
- Formats: Geotiff (.TIF)
- Maximum Resolution: 1m DEM (higher resolutions are supported but will be downsampled to 1m resolution)
Terrain TIN
- Type: Aerial Laser Scan
- Formats: Lidar (.LAS)
- Maximum Resolution: 32 ppm recommended (higher is possible but may affect loading performance – contact Urban Circus for details)
- Ground Classified as Category 2 (Other classifications can be included in the source data, however they will be ignored during terrain generation. Unclassified data not supported)
Imagery
- Type: Aerial Imagery
- Imagery: Erdas ECW (.ecw), Geotiff (.TIF).
- Maximum Resolution: 10cm