ArcGIS 3-D Analyst - PowerPoint PPT Presentation

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ArcGIS 3-D Analyst

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Draw the perpendicular bisectors of each edge of the triangle ... surface change (e.g. streams, ridges, road kerbs, building footprints, dams) ... – PowerPoint PPT presentation

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Title: ArcGIS 3-D Analyst


1
ArcGIS 3-D Analyst
2
Triangulated Irregular Network (TIN)
3
A Mesh of Triangles
Triangle is the only polygon that is always
planar in 3-D
Lines
Surfaces
Points
4
Tin Triangles in 3-D
(x3, y3, z3)
(x1, y1, z1)
(x2, y2, z2)
z
y
Projection in (x,y) plane
x
5
Delauney Triangulation
Maximize the minimum interior angle of
triangles No point lies within the circumcircle
of a triangle
Yes
No
6
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

7
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.

8
TIN for Waller Creek
9
TIN with Surface Features
Classroom
UT Football Stadium
Waller Creek
10
A Portion of the TIN
11
Input Data for this Portion
Mass Points
Soft Breaklines
Hard Breaklines
12
TIN Vertices and Triangles
13
TIN Surface Model
Waller Creek
Street and Bridge
14
3-D Scene
15
3-D Scene with Buildings
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