3D Analyst
Components
• ArcScene
– Is where 3D Analyst is located
– Visualization and Some Analysis
• ArcGlobe
– Like Google Earth – google’s is better
• ArcMap - does NOT display 3D!
• ArcCatalog – can preview in 3D
3D Data
• Has a Z value
• Elevation is most common Z value
• But can also represent
– Pollution levels
– Noise levels
– Precipitation …. Etc.
Kinds of 3D data structures
• DEM raster
• TIN (Triangulated
Irregular Network)
TIN
• Every 3
points of Z
are
connected
to make a
Triangle w/
Area, Slope,
and Aspect.
3D view
•
•
•
•
•
•
Open ArcScene
Load DEM or TIN
Raster will be flat!
Set base height
Set vertical exaggeration
Illumination of DEM
Navigation tools different
• General nav tool
• Zoom tool
Fly tool
• Guess what?
• Expand field of view
• Narrow Field of View
Done while we go
through these
demos
Vertical Exaggeration
• Why?
– used to emphasize small changes
– bring z-units into proportion with x,y
units
• It is a only visual effect that does
NOT affect analysis
Illumination
• Every Scene has a light source – the sun
• Thus different parts of the scene are
illuminated differently
• The sun’s position is described by…
– The sun’s azimuth is measured from 0 (north)
to 360 (north) ccw. (315 (NW) is default)
– The sun’s altitude (0-90) is its height above
the horizion.
Layer Properties
• Base Heights
– establishes the elevations of surface
locations and features.
• Extrusions
– tells 3D Analyst how high a feature rises
above the ground or extends below it.
Base Heights
• Elevation values that are used to
display a layer in 3D.
• These values can come from various
places.
– layer:
•
•
•
•
the node elevations in a TIN,
the cell values in a raster,
the z-values in a 3D feature layer,
or the elevation attribute values for a 2D
feature layer.
Rendering
• In layer’s properties
• Scene Layer properties
Extrusions
• three-dimensional extension of
features.
– An extruded point  a line;
– an extruded line  a wall;
– an extruded polygon  a chunk.
• There are many methods used to do
this
Surface Calculations
•
•
•
•
•
•
Slope
Aspect
Hillshade
Contours
(Reclassification)
Pretty much the same as ArcGIS but
tools in 3D Analyst Tools
Adding 2D data
• Turning on in TOC does not do much –
maybe can’t even see it!
• Have to set the layer’s elevations
– Layer properties/Base Heights from
DEM