Certified Photogrammetrist Stereo Compilation & 3D Modeling 2

Question 1

What is 'relief displacement' in aerial photography?

Accepted Answer

The shift of elevated objects outward from the nadir point on a vertical photograph

Answer

Relief displacement is the radial outward shift of elevated objects from the nadir point on a vertical aerial photograph, caused by the perspective projection of terrain relief.

Question 2

What is a TIN (Triangulated Irregular Network) in 3D modeling?

Accepted Answer

A surface model composed of irregular triangular facets connecting measured mass points and breaklines

Answer

A TIN is a vector-based surface model made of irregular triangular facets connecting measured points and breaklines, faithfully representing terrain morphology including sharp features like ridges.

Question 3

What is 'breakline' collection in stereo compilation?

Accepted Answer

Collecting linear features (ridgelines, drainage lines, roads edges) that define sharp changes in terrain slope for accurate TIN and DEM generation

Answer

Breaklines are collected along ridges, streams, road edges, and other features representing abrupt slope changes, ensuring that TINs and DEMs accurately model terrain discontinuities.

Question 4

What is 'mass point collection' in stereo compilation?

Accepted Answer

The systematic collection of random elevation measurements across the terrain to support TIN and DEM generation

Answer

Mass point collection involves systematically measuring a large number of random elevation points across the terrain, providing the raw data needed to build an accurate TIN or DEM surface model.

Question 5

In 3D city modeling, what is 'Level of Detail' (LOD) as defined by CityGML?

Accepted Answer

A hierarchical scale of model complexity, from simple block models (LOD1) to fully textured models with interior detail (LOD4)

Answer

CityGML defines LOD (Level of Detail) as a hierarchy from LOD0 (footprint) through LOD1 (block), LOD2 (roof structures), LOD3 (facades), to LOD4 (interior elements), reflecting increasing geometric complexity.

Certified Photogrammetrist Practice Test

Certified Photogrammetrist Practice Test

Certified Photogrammetrist Stereo Compilation & 3D Modeling 2