1.13.1. Measurement of distance by chain or tape

The distance could be measured on level ground or sloping ground with a chain or a tape in a similar manner. On the ground, the line to be measured is marked at both ends and also at intermediate points, wherever necessary, in the same alignment direction.

This chunk introduces the basic concept of measuring distance using chains or tapes. It states that measurement can occur on both level and sloping ground. To correctly measure distance, surveyors first identify and mark the starting and ending points of the measurement. Additionally, if necessary, they may mark intermediate points to maintain a straight alignment throughout the measurement process.

Imagine walking a straight path to a friend's house. You mark out where your house is (start) and where your friend's house is (end). If the path has bumps (like sloping ground), you might also place markers along the way to keep your path straight. This way, when you measure the distance, you ensure a more accurate result.

The chain or tape is laid on the ground in the alignment direction, and a peg is inserted at the other end. The chain or tape is again brought where the peg was inserted and full chain/tape length is again measured and another peg is inserted. The process continues till end point of the line is reached. The total distance is thus computed by adding up all the distances.

After marking the points, the surveyor lays the chain or tape along the predetermined line direction. A peg is driven into the ground at the end of the chain or tape. Then, the surveyor brings the other end of the chain or tape to this peg to measure the full length again, inserting a new peg to indicate the new measured endpoint. This process is repeated until the final endpoint is reached, and the total distance is calculated by summing all the measured lengths. Essentially, the surveyor is progressively measuring small segments and compiling them for a total.

Think of stretching a jump rope from your house to your friend's house. You first place a marker at the end of your rope and then look back to see how much more rope you need to reach their house. Every time you find a new mark, you add that to your total distance. Finally, when you collect all the segments, you see how far apart you are.

On uneven or sloping ground, the distance is directly measured in small stretches by keeping the chain/tape horizontal (by eye judgement only). This distance is measured and the chain/tape point at other end is projected on the ground with the help of a plumb bob, and marked with a peg.

When the ground is not level, surveyors adapt their technique. They try to keep the chain or tape horizontal, which may require visual estimation, as the equipment cannot be directly laid flat. After measuring a segment, they project where the opposite end should be on the ground, often using a plumb bob, which is a tool that shows the vertical downward line from a point. A peg is then placed to mark this projected point, and the process is repeated until the endpoint is reached.

Imagine climbing a hill while trying to measure how far you climb horizontally. Just like trying to keep a string level while walking up a slope, you measure small sections carefully to keep your distance accurate. The plumb bob acts like dropping a string from your hands down to know where to put your next marker.

The total distance is thus computed by adding up all the distances. Since, this approach provides rough measurements, now-a-days this method is not used on sloping ground.

After measuring different sections, the surveyor sums all the segments to find the total distance. It's noted that while this method was practical, modern surveying technology has made it less popular for sloped terrain due to potential inaccuracies in estimation. As technology has evolved, methods like Electronic Distance Measurement (EDM) have provided more precise distance measurements.

If you were to assemble multiple pieces of string to measure a longer distance, you’d add up the lengths of each piece to get the total. However, if you had a tool like a measuring wheel that could do it all at once, you would likely prefer that for efficiency and accuracy.

If the length to be measured is very large, the direction of measurement is determined by a process called ranging so that all the measurements fall in a straight line.

For longer distances, surveyors use a technique called 'ranging'. This process helps ensure that measurements maintain a straight line over long distances. Instead of repeatedly measuring small sections, ranging establishes accurately spaced points in a straight path for the measurements to fall in line. Newer tools like Electronic Distance Measurement (EDM) devices and Total Stations have made this even more efficient and accurate.

Consider playing a game of darts where you want to hit a target. Initially, you might line up each dart individually, but eventually, you'd want to find a better tool or set-up that helps you aim and hit that target accurately from a distance, ensuring every throw counts!

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