Photogrammetry — Slotted template method overview for aerial triangulation Which of the following statements correctly describe the slotted template method used in planimetric plotting and radial triangulation over large mapping blocks?

Introduction / Context:
The slotted template method is a classic graphical technique in photogrammetry used to extend control and assemble aerial photographs into a coherent block for mapping. Although largely superseded by analytical and digital aerotriangulation, it remains an important conceptual foundation because it illustrates how parallax-based geometry can be solved graphically with speed and acceptable accuracy for many engineering applications.

Given Data / Assumptions:

• The method uses overlapping vertical photographs with approximate camera constants known.
• Ground control points may be few; the aim is to bridge gaps using relative orientation.
• Templates are prepared from photo centers, principal points, and fiducial geometry.

Concept / Approach:

In the slotted template method, each photo (or model) is represented by a transparent sheet with carefully cut slots. These slots allow pins at approximate control locations to slide so that adjacent models can be rotated and translated relative to each other until their tie points coincide. The graphical fit distributes small errors across the block, giving a consistent assembly for planimetric plotting and height transfer where needed.

Step-by-Step Solution:

Verification / Alternative check:

Checks include closure around circuits and comparison with known ground control. Small residuals indicate satisfactory accuracy for the intended map scale.

Why Other Options Are Wrong:

• Each of options (a)–(d) is true for the slotted template method; therefore the comprehensive choice is correct.

Common Pitfalls:

• Poor slot cutting or inaccurate transfer of fiducials leads to cumulative misfits.
• Insufficient tie points can cause local distortions when templates are locked.

Final Answer:

All the above.