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3-D Temporal GIS
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Horizontal sure, but .

• how to deal with elevation/depth or time
• Vertical
• Horizontal and vertical
• Horizontal, vertical, and time

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ArcScene 9 Demo
http//dusk.geo.orst.edu/gis/captivate_arcscene/ar
cscene_demo.htm
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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

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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

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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

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Coastal Terrain Model
USGS Topography
a surface that integrates topography and
bathymetry
Integrated Topo-Bathy Model
Bathymetry
Topography


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Satellite Imagery Draped on Topo-bathy model
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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

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Perspective Plot from TIN (2.5-D B-Rep)
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B-Rep of a Cave Passage
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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 zs possible for a single x-y pair,
• soundings in the ocean or atmosphere, geologic
  logs of wells

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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

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Fonseca, Mayer, and Paton in Wright (ed.)
Undersea with GIS published by ESRI Press
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Fonseca, Mayer, and Paton in Wright (ed.)
Undersea with GIS published by ESRI Press
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FledermausInteractive Visualization
Systemswww.ivs3d.com
http//dusk.geo.orst.edu/gis/captivate_ivs/ivs1.ht
m
http//dusk.geo.orst.edu/gis/captivate_ivs/ivs2.ht
m
http//dusk.geo.orst.edu/gis/captivate_ivs/ivs3.ht
m
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Volumes

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

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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
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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

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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

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SOE of a Mine/Quarry
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Commercially Available?

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

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You knew I had to mention itGOOGLE EARTH
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Sketch Ups and Touch Tables

• Insert your own objects
• Google Ocean
• Visualize with your hands
• http//www.youtube.com/watch?vX2pPeW4cUgUfeature
  PlayListpFB02B6AD35983A48playnext1index14
• http//www.youtube.com/watch?vW3dz2xpCJVUfeature
  related

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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

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

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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"