Heightmap terrain

A heightmap represents terrain as a regular grid of elevations. Configure visual and collision geometry together so the seabed seen by a camera agrees with the surface used for contact.

Example terrain

Use Santorini for a geographic scene and graded seabed for a seabed scene. Santorini uses the Fuel model Santorini Scaled.

These examples show world composition. For heightmap geometry itself, follow Gazebo's heightmap tutorial and the SDFormat geometry reference.

Keep terrain assets inside the package

Place a new world in models/posim_worlds/worlds and its data under models/posim_worlds/media. Inspect the package's CMake install rules and resource hook. Use installed, portable URIs rather than an absolute developer path.

The geometry inside a visual or collision takes this general form:

<geometry>
  <heightmap>
    <uri>model://media/meshes/my_heightmap.png</uri>
    <size>1000 1000 80</size>
    <pos>0 0 -80</pos>
  </heightmap>
</geometry>

This fragment is an illustration for your own asset. Select a raster format and sampling supported by the renderer and physics backend. Check the elevation encoding before choosing the vertical size and offset.

Preserve coordinates and scale

size gives horizontal extent and elevation scale in meters; pos supplies an offset. A normalized image is not automatically a georeferenced elevation raster. Record source extent, elevation range, sea-level reference and any reprojection or resampling.

Set the world origin with <spherical_coordinates> when geographic positions matter. See Spherical coordinates to transform between latitude/longitude and local coordinates.

Build and verify

Rebuild and source the workspace after adding resources. Launch the new world from outside the checkout. Check recognizable elevation landmarks, the visual/collision alignment, sensor depth and a controlled contact probe. Confirm the intended sea level and robot start height before using the terrain in navigation experiments.