Mars Oceans Visualisation
Visualisation: December 2019, Movie render: August 2020
A visualisation of the Martian planet surface and topography created from public domain data obtained from the USGS Astrogeology Science Center:
- Mars Viking Global Color Mosaic 925m v1 https://astrogeology.usgs.gov/search/map/Mars/Viking/Color/Mars_Viking_ClrMosaic_global_925m
- Mars MGS MOLA - MEX HRSC Blended DEM Global 200m v2 https://astrogeology.usgs.gov/search/map/Mars/Topography/HRSC_MOLA_Blend/Mars_HRSC_MOLA_BlendDEM_Global_200mp
The equirectangular colour and DEM images are first converted to 6 cube map faces and applied to a set of 6 normalised cube-face meshes for a more regular mapping of the sphere surface without pinching artifacts at the poles. Topography height is exaggerated times three to better highlight features from a distant perspective.
The base planet rendering is similar to, and was inspired by, an early visualisation displayed at the Monash CAVE2 facility from Robert Kooima of the University of Illinois in Chicago's Electronic Visualization Lab here.
Using a custom set of shaders, a dynamic visualisation was created to allow exploration of how the planet and it's topographical features might appear under varying levels of ocean height by simulating the appearance of water at user-defined height levels.
To create this animation the water height is raised incrementally as the planet rotates. Lighting and motion attempts to recreate the actual characteristics of the rotation of the planet Mars, with its 25 degree axial tilt towards the sun and anti-clockwise rotation looking from the north pole.
At lower terrain level of detail (2048 x 2048 x 6) the frame rate is high enough to allow the model to be interactively explored, the animations were produced at full terrain detail (4096 x 4096 x 6).
Visualisation was created using LavaVu https://github.com/lavavu/LavaVu/
References:
Fergason, R. L, Hare, T. M., & Laura, J. (2018). HRSC and MOLA Blended Digital Elevation Model at 200m v2. Astrogeology PDS Annex, U.S. Geological Survey. http://bit.ly/HRSC_MOLA_Blend_v0
Albee, A. L., Arvidson, R. E., Palluconi, F., & Thorpe, T. (2001). Overview of the Mars Global Surveyor mission. Journal of Geophysical Research, 106(E10), 23291–23316. https://doi.org/10.1029/2000JE001306
Batson, R. M., & Eliason, E. M. (1991). Digital Maps of Mars. Photogrammetric Engineering & Remote Sensing, 61(12), 1499–1507.https://www.asprs.org/wp-content/uploads/pers/1995journal/dec/1995_dec_1499-1507.pdf
Kooima, Robert, Jason Leigh, Andrew Johnson, Doug Roberts, Mark SubbaRao, and Thomas A. DeFanti. "Planetary-scale terrain composition." IEEE Transactions on Visualization and Computer Graphics 15, no. 5 (2009): 719-733.
Owen Kaluza, Louis Moresi, John Mansour, & David G Barnes. (2019, March 6). OKaluza/LavaVu: v1.3.2 (Version 1.3.2). Zenodo. http://doi.org/10.5281/zenodo.2585377
