Plane Table Size: Understanding the Standard Dimensions

Plane table surveying is a graphical method used in fieldwork where the surveying instruments are mounted on a plane table, allowing direct plotting of field details onto a drawing sheet. The size of the plane table is an important specification that affects its portability and the scale at which details can be plotted.

Why Plane Table Size Matters

The dimensions of the plane table are chosen to balance portability for fieldwork with sufficient surface area for accurate drawing and plotting at a reasonable scale. A larger table allows for plotting at a larger scale or capturing more detail in a single setup, but it can be heavier and less convenient to handle in the field.

Analyzing the Options

The question asks for the standard size of a plane table. Let's look at the common dimensions provided:

• Option 1: $750 \text{ mm} \times 900 \text{ mm}$
• Option 2: $600 \text{ mm} \times 750 \text{ mm}$
• Option 3: $450 \text{ mm} \times 600 \text{ mm}$
• Option 4: $300 \text{ mm} \times 450 \text{ mm}$

Standard Plane Table Dimensions

In practice, the most commonly used and standard size for a plane table board is $600 \text{ mm} \times 750 \text{ mm}$. This size provides a good working area for most surveying tasks, allowing for plotting at scales typically used in topographic and cadastral surveys. While smaller or larger tables exist for specific purposes, the $600 \text{ mm} \times 750 \text{ mm}$ dimension is widely adopted as the standard.

The other sizes listed are less common as standard sizes. For instance, $450 \text{ mm} \times 600 \text{ mm}$ might be considered a smaller, more portable option, while $750 \text{ mm} \times 900 \text{ mm}$ would be quite large for typical field use. The $300 \text{ mm} \times 450 \text{ mm}$ size is generally too small for effective plane table work.