Each cell contains two elements: neighborhood relationships / assumptions, plus the classification in class 0, 1A, 1N or 2. (See Table 9-2).
Implicit Implied by matrix or triangle neighbors (connectivity in data structure)
Found Must be found by geometric process
Point in Triangle Point in triangle (simplified overlay)
Imported External, must be imported
Flat triangle Assumption basic to TIN structure
The conversion from TIN to TIN either Simplifies or Refines, if it drops points/triangles (reduction in information) or adds new triangles/points from some external source (gain in information).