ArcGIS 3-D Analyst

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ArcGIS 3-D Analyst
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Triangulated Irregular Network (TIN)
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A Mesh of Triangles
Triangle is the only polygon that is always
planar in 3-D
Lines
Surfaces
Points
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Tin Triangles in 3-D
(x3, y3, z3)
(x1, y1, z1)
(x2, y2, z2)
z
y
Projection in (x,y) plane
x
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Delauney Triangulation
Maximize the minimum interior angle of
triangles No point lies within the circumcircle
of a triangle
Yes
No
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Circumcircle of Triangle

• Draw the perpendicular bisectors of each edge of
  the triangle
• Circumcircle is centered on their intersection
  point
• Radial lines from center have equal length

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Inputs for Creating a TIN

• Hard breaklines define locations of abrupt
  surface change (e.g. streams, ridges, road kerbs,
  building footprints, dams)
• Soft breaklines are used to ensure that known z
  values along a linear feature are maintained in
  the tin.

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TIN for Waller Creek
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TIN with Surface Features
Classroom
UT Football Stadium
Waller Creek
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A Portion of the TIN
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Input Data for this Portion
Mass Points
Soft Breaklines
Hard Breaklines
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TIN Vertices and Triangles
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TIN Surface Model
Waller Creek
Street and Bridge
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3-D Scene
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3-D Scene with Buildings