Definitions for "Triangulated Irregular Network"
a contouring method of linear interpolation that bases its predicted surface on the flat plane that can be fitted to any three non-collinear points. It assumes that point observations represent exact values and that the sampling has been carried out at sufficient detail to fit a continuous surface.
See digital terrain model -- TIN.
data structure, normally used in connection with terrain modeling, that describes a three-dimensional surface as a series of irregularly shaped triangles.