Post on 11-Feb-2016
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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