Concepts / generalizations

1. Distance can be measured by Pacing

The length of a person’s pace may vary.
The average of a person’s pace can be used to measure between two places by counting the number of paces and using that with the average length of the pace to measure the distance.
A person can measure the length of a pace by counting the number of paces a person makes over a known distance and find an average.

2. The position of an object can be located from a baseline if the distance along the baseline, from a benchmark/ datum, is known and the distance to a point at a 90-degree angle from the baseline.

A baseline is a straight line from a benchmark/ datum.
A baseline can be visualized with a string or cord attached to a benchmark/ datum and pulled straight.

3. Positions of objects or features can be located to a benchmark/ datum, by triangulation. Triangulation is a procedure used to locate positions by dividing a region into a series of triangular pieces based on lines of known length that intersect at the point to be located; and the other ends of the lines join the base of a triangle of known length between a benchmark/ datum and another know point (another selected benchmark/ auxiliary datum)

4. Positions of objects can be located from a benchmark/ datum with a direction (azimuth) and distance. Direction of an object can be measured in degrees using a transit located at a benchmark to measure the angle of declination from north (azimuth). Distance can be measured from the same benchmark to the object using paces or measuring cord.

5. Contours can be mapped by measuring distance from a baseline. A baseline used to measure contours can be made by extending a cord over the contour so that it is level, measuring intervals of distances from a benchmark/ datum/ (start of the baseline) along the cord and then measuring the distance from the points on the cord of each interval distance to the point on the contour directly below (perpendicular to) the cord/baseline.

6. The height of a tree, flagpole, building or some other object can be measured with a grade/slope/angle/ and a known distance.

The grade/slope/angle of a surface can be measured with a clinometer.