Augmented Reality iGeology3D Use Cases

Visualising Geoscience Information At and Around a Location

User Story: Interested amateur geologist

• What is the rock I am standing on?
• What are the different rocks I can see on the hillside in front of me?
• What rocks are below the ones I can see on the surface?

User Story: Geological consultant

Example Data Sets

• Digital Terrain Model: a representation of the Earth surface elevations. Used to construct the 3D shape of the ground, replicating the view of the landscape hills and valleys from the user's position.
• Raster map tiles: WMS or other rasters used to paint the DTM surface.
• Surface geology polygons with attributes such as rock classification: vector map data used to retrieve attributes for a position when the user taps on the screen representation of the landscape. These could also be used instead of rasters for painting the DTM surface but rasters are faster at present.
• Surface geology lines with attributes e.g. faults, used to retrieve attributes for a position.
• Surface geology points with attributes e.g. borehole locations.
• Other surfaces below ground: e.g. geological layer boundaries, fault surfaces (often very steep)
• Vertical sections: a "fence" of vertical panels hung down from the terrain surface described by vertical polygons with attributes such as rock classification.
• Below ground borehole paths: 3D lines with attributes relating to segments, such as rock classification.

Levels Of Detail

• For a realistic augmented reality view in a mountainous landscape the simulated view needs to show upto 40km in all directions.

• Close up, the more detail the better. iGeology3D uses 5m or 10m horizontal spacing for a gridded DTM at the highest level of detail.

• Further away the eye and screen can resolve less detail. Halving the data resolution as the distance doubles preserves aparent resolution while minimising the data volumes.

• Care must be taken with tiled surface when changing between close and more distant LODs - the edges must match exactly, gaps are very obvious.

• Generalising terrain surfaces can give poor results for augmented reality if the skyline isn't preserved. A lot of detail is visible on the ridge lines of distant mountains with sky behind them.