Triangulated Irregular Network (TIN) is a digital representation of a surface as non-overlapping triangles computed from irregularly spaced 3D points, where each point has x, y, and z coordinates. TINs are useful for representing continuous surfaces in GIS as they can accurately model terrain with significant slopes and variations while using fewer triangles in flat areas. TINs allow for easy derivation and analysis of surface properties like slope, aspect, area, and volume from mass point data, contours, and breaklines.

1. Triangulated Irregular Network (TIN)
ROHIT KUMAR
GEO-INFORMATICS
CUJ/I/2013/IGIO/26

2. DEFINATION
• TIN is a set of adjacent, non-overlapping
triangles computed from irregularly spaced
points, with x, y horizontal coordinates and z
vertical elevations.

3. Advantages & Disadvantages
• Advantages
– Can capture significant slope features (ridges, etc)
– Efficient since require few triangles in flat areas.
– Easy for certain analyses: slope, aspect, volume.
• Disadvantages
– Analysis involving comparison with other layers difficult.

4. • TINs
– are the most useful method for representing a continuous
surface in a vector GIS system.
– data sets comprising any combination of contours,
breaklines and point elevations (either DEM or massed
points) can be combined as input to create a TIN
• TINS are especially useful for analytical purposes
• Good model for representing surfaces
• slope and aspect easily derived
• simplify the calculation of surface area and volume
TIN as a Storage Method

5. Tin Triangles in 3-D
(x3, y3, z3)
(x1, y1, z1)
(x2, y2, z2)
x
y
z
Projection in (x,y) plane

6. Inputs for Creating a TIN
Mass Points Soft Breaklines Hard Breaklines
• 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.

7. A Portion of the TIN

8. Input Data for this Portion
Mass Points
Soft Breaklines
Hard Breaklines

9. TIN Vertices and Triangles

10. TIN Surface Model
Waller
Creek
Street and
Bridge

11. 3-D Scene

12. 3-D Scene with Buildings

13. THE END
THANK
YOU