Horizontal Distance Measurement

Using tape to measure plan distances

Standard Equipment

The standard instrument used for measuring horizontal distances is the Steel Tape. A Constant Tension Handle is usually applied as well. Since both ends of the tape need to be firmly and accurately held, taping is usually a two man operation.

Basic Measurement between 2 points

  1. Locate the two points. Make sure your tape is long enough to reach between them.
  2. At the zero end of the tape, it is easier to hold the tape with 1m at the first point rather than zero. This is generally referred to as "one metre on". This end of the tape should be held firmly against the first point.
  3. Ensure that the tape is not kinked or twisted, and is in a staright line.
  4. Using the constant tension handle, pull the tape taut at the second point. read off the distance on the tape, but don't forget to subtract the extra metre. Note this in the record, ie. " xxxxx - 1", to remind yourself that the correction has already been applied.
  5. Always measure the distance independantly at leats twice.

Correction Factors

Whilst the basics of measuring a distance with a tape are very simple, there are a number of correction factors that can be taken into account.

Corrected Distance =
Measured distance + (1) + (2) + (3) + (4) + (5),

Where (1) to (5) are:-

  1. Slope Correction
  2. Standardisation
  3. Tension Correction
  4. Temperature Correction
  5. Sag/Catenary Correction

For accuracies of 1:5000 to 1:10000 you need only apply (1) and (2).
For 1:10000 to 1:20000 apply (1), (2), (3), and (4).
For accuracy greater than 1:20000 use all 5 corrections.

Or select Back to return to the main selection screen.