Plane table and drafting tools – function of a pantograph In mapping and drafting practice, a pantograph is primarily used for which operation on maps and plans?

Introduction / Context:Classical surveying and drafting employ mechanical aids to prepare drawings at different scales. Among them, the pantograph enables the accurate reproduction of a plan at an enlarged or reduced scale without redrawing each feature by hand. This question asks you to identify the chief function of a pantograph in the workflow of mapping and drafting.

Given Data / Assumptions:

• A pantograph is a linked-arm mechanism with adjustable pivot points.
• It transfers motion proportionally from a tracing point to a drawing point.
• Scale ratio is controlled by the geometry of the linkages and fixed points.

Concept / Approach:

By fixing the tracer, pivot, and pencil points at specific holes in its arms, a pantograph creates a mechanical similarity transformation. Tracing over an original plan produces a copy whose lengths are multiplied by a constant factor (greater than 1 for enlargement, less than 1 for reduction). This is particularly handy for producing plan sets at different scales for presentation or site use.

Step-by-Step Solution:

Verification / Alternative check:

Drafting manuals list the pantograph under copying and scaling devices, distinct from planimeters (for area measurement) or chains/tapes (for distance measurement).

Why Other Options Are Wrong:

Measuring distances/areas: Distances are measured with scales or tapes; areas with planimeters or counting methods, not a pantograph.

Setting out right angles: That is done with optical squares, theodolites, or cross-staffs.

Common Pitfalls:

Confusing pantographs with planimeters; expecting direct area outputs rather than scaled copies; ignoring setup geometry that controls the scale factor.

Final Answer:

Enlarging or reducing existing plans to a different scale