Triangulated Irregular Network

(TINTIN)A set of adjacent, non-overlapping

triangles computed from irregularly spaced points with x, y

coordinates and z values.

Surface ConceptsSurface Concepts

• Discrete vs. Continuous features– Discrete features;

• roads,

• land ownership,

– Continuous features;• elevation,

• Rainfall data,

• Pollution concentration

What is a TIN ?What is a TIN ?

• Tin data structure based on two basic elements to form a continuous faceted surface.

»Points with x,y,z values

»Series of edges

What is a TIN ? What is a TIN ? (cont.)(cont.)

• The triangles are as equi-angular as possible

• Ensures that any point on the surface is as close as possible to a node

• The triangulation is independent of the order the points are processed

Components of a TINComponents of a TIN

• Nodes

• Edges

• Trangles

What is a Lattice ?What is a Lattice ?

• A surface interpretation of a grid– Equally spaced sample points– Referenced to a common origin – Constant sampling distance in the x and y

directions

What do TINs Look Like ?

TIN in ArcInfo

Arc: TINARC

Usage: TINARC <in_tin> <out_tin> {POLY | LINE | POINT | HULL}

{PERCENT | DEGREE | Z_FACTOR}

• END