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“3-D” & Temporal GIS

“3-D” & Temporal GIS. Horizontal sure, but …. . how to deal with elevation/depth or time Vertical Horizontal and vertical Horizontal, vertical, and time. ArcScene 9 Demo. http://dusk.geo.orst.edu/gis/captivate_arcscene/arcscene_demo.htm. The Vertical Dimension.

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“3-D” & Temporal GIS

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  1. “3-D” & Temporal GIS

  2. Horizontal sure, but …. how to deal with elevation/depthor time • Vertical • Horizontal and vertical • Horizontal, vertical, and time

  3. ArcScene 9 Demo http://dusk.geo.orst.edu/gis/captivate_arcscene/arcscene_demo.htm

  4. The Vertical Dimension • two very different ways of looking at representations of the vertical dimension (third dimension) in GIS • “2.5-D” and “3-D” • vertical dimension combined with temporal query = “4-D”

  5. “2.5 D” • most common way of “doing 3D” in commercial GIS packages • z value (normally elevation) is recorded as an attribute for each data point (x,y) • z values can be used in a perspective plot to create the appearance of 3 dimensions • not true 3-D representation because elevation is not encoded in data structure, not in topology

  6. 2.5 D Representations • attractive displays of topography and other continuous surfaces from DEMs or TINs • perspective plots computed from any viewpoint • additional layers "draped" over the surface

  7. USGS Topography “Coastal Terrain Model” …a surface that integrates topography and bathymetry Integrated Topo-Bathy Model Topography Bathymetry + =

  8. Satellite Imagery Draped on Topo-bathy model

  9. Boundary Representation • TIN is a 2.5 D type of B-rep • one value of z for every x,y • each object has faces, edges, points

  10. Perspective Plot from TIN (2.5-D B-Rep)

  11. B-Rep of a Cave Passage

  12. True 3-D • store data in structures that actually reference locations in 3D space (x,y,z) • here z is not an attribute but an element of the location of the point • if z is missing, object does not exist! • several z’s possible for a single x-y pair, • soundings in the ocean or atmosphere, geologic logs of wells

  13. 3-D Applications • geological/geophysical exploration • engineering design of mines, quarries, dams, reservoirs, etc. • scientific explanation of 3D processes such as ocean currents or lava flows • “data driven” - may not necessarily know what you will find in 3D • so the structure of the representation may enhance types of analyses that can be performed

  14. Fonseca, Mayer, and Paton in Wright (ed.) Undersea with GIS published by ESRI Press

  15. Fonseca, Mayer, and Paton in Wright (ed.) Undersea with GIS published by ESRI Press

  16. “Fledermaus”Interactive Visualization Systemswww.ivs3d.com http://dusk.geo.orst.edu/gis/captivate_ivs/ivs1.htm http://dusk.geo.orst.edu/gis/captivate_ivs/ivs2.htm http://dusk.geo.orst.edu/gis/captivate_ivs/ivs3.htm

  17. Volumes • visualization of volumes • modeling of volumes • algorithms for 3D spatial analysis simpler, more efficient, if data in a volumetric form

  18. Example two: Hydrothermal Plume model output VTK/Java3D allows volume calculations, rendering, and analysis. • 3D probe • animation • bathymetry • multibeam • Smith/Sandwell Vance et al., NOAA Alaska Fisheries Science Center

  19. Underwater Behavior of Humpback Whales: Potential Entanglement in Fishing Gear Stellwagen Bank National Marine Sanctuary - Ware et al., Center for Coastal and Ocean Mapping, U. of New Hampshire

  20. Spatial Occupancy Enumeration(SOE) • volume is divided into cubes or voxels • usually produced by converting from B-reps (similar to converting vectors to rasters in 2D) • mass, volume and surface area are quickly computed as Boolean operations [on (full) / off (empty)] or voxel counts

  21. Surface Water Runoff Gold, Transactions in GIS, 2006 SOE of a Mine/Quarry

  22. Commercially Available? • Research frontier • not too many truly 3D GIS packages on the market • 2- or 2.5D GIS linked to 3D modeling package

  23. You knew I had to mention it…GOOGLE EARTH

  24. Sketch Ups and Touch Tables • Insert your own objects • Google Ocean • “Visualize” with your hands • http://www.youtube.com/watch?v=X2pPeW4cUgU&feature=PlayList&p=FB02B6AD35983A48&playnext=1&index=14 • http://www.youtube.com/watch?v=W3dz2xpCJVU&feature=related

  25. Time Dependence • time dependence adds a third dimension to spatial data, just as the vertical dimension does • or may be added to 3 spatial dimensions to give 4D

  26. Coastal Evolution of OR/WA Cross & Twichell, USGS Woods Hole in Wright (ed.) Undersea with GIS, ESRI Press, 2002.

  27. Time and Geographical Data • computer science has dealt with time dependence of records in databases • e.g., records may be valid only for limited times • geographical cases are more complex - • objects may have limited existence, but may also move, change shape, and change attributes • database models for time? few “temporal GISs” on the market • Tracking Analyst for ArcGIS

  28. Dealing with Time in GIS • shape of objects same, but attributes change • same shape, same attributes, but boundaries between objects or locations of objects change • Turn on/off or move • shapes of objects change through time • define a limited number of time "slices"

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