“3-D” & Temporal GIS

“3-D” & Temporal GIS

Horizontal sure, but ….

how to deal with elevation/depth or time

VerticalHorizontal and verticalHorizontal, vertical, and time

ArcScene 9 Demo

http://dusk.geo.orst.edu/gis/captivate_arcscene/arcscene_demo.htm

The Vertical Dimensiontwo 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”

“2.5 D”most common way of “doing 3D” in commercial GIS packagesz 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 dimensionsnot true 3-D representation because elevation is not encoded in data structure, not in topology

2.5 D Representationsattractive displays of topography and other continuous surfaces from DEMs or TINsperspective plots computed from any viewpointadditional layers "draped" over the surface

“Coastal Terrain Model”USGS Topography

+ =

Integrated Topo-Bathy Model

BathymetryTopography

…a surface that integrates topography and bathymetry

Satellite ImageryDraped on Topo-bathy model

Boundary RepresentationTIN is a 2.5 D type of B-rep

one value of z for every x,y each object has faces, edges, points

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

B-Rep of a Cave Passage

True 3-Dstore 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

3-D Applicationsgeological/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 3Dso the structure of the representation may enhance types of analyses that can be performed

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

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

“Fledermaus”Interactive Visualization Systemswww.ivs3d.comhttp://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

Volumesvisualization of volumesmodeling of volumes

algorithms for 3D spatial analysis simpler, more efficient, if data in a volumetric form

Example two: Hydrothermal Plume model output

VTK/Java3D allows volumecalculations,rendering, and analysis.

● 3D probe● animation● bathymetry

● multibeam● Smith/Sandwell

Vance et al., NOAA Alaska Fisheries Science Center

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

Spatial Occupancy Enumeration(SOE)

volume is divided into cubes or voxelsusually 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

SOE of a Mine/Quarry

Surface Water Runoff

Gold, Transactions in GIS, 2006

Commercially Available?Research frontiernot too many truly 3D GIS packages on the market2- or 2.5D GIS linked to 3D modeling package

You knew I had to mention it…GOOGLE EARTH

Sketch Ups and Touch TablesInsert your own objects

Google Ocean“Visualize” with your hands

http://www.youtube.com/watch?v=X2pPeW4cUgU&feature=PlayList&p=FB02B6AD35983A48&playnext=1&index=14http://www.youtube.com/watch?v=W3dz2xpCJVU&feature=related

Time Dependencetime dependence adds a third dimension to spatial data, just as the vertical dimension doesor may be added to 3 spatial dimensions to give 4D

Coastal Evolution of OR/WA

Cross & Twichell, USGS Woods Hole in Wright (ed.) Undersea with GIS, ESRI Press, 2002.

Time and Geographical Datacomputer 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

Dealing with Time in GISshape of objects same, but attributes changesame shape, same attributes, but boundaries between objects or locations of objects change

Turn on/off or moveshapes of objects change through time

define a limited number of time "slices"