ON-SITE MEASUREMENT SYSTEMS

As can be seen, four separate measurements could have been taken in the
Figure 6-16
Use a screwdriver to secure one
end of the tape measure. Two people can more accurately locate both ends of the tape measure and pull it taut to ensure correct measurements. However, moving the tape measure con­sumes time and increases the possibility of misreading the tape measure. preceding example (bottom of Figure 6—18). When the circles are drawn on the base map, they will intersect at the center point of the tree. Triangulation The triangulation method of measuring is used to locate a point in relation to two other known points. Simply measure and record the distance from each house corner to the center of the tree. The top half of Figure 6—18 shows the tape measure stretched from the face of a house to the nearby property line. Direct Measuring Direct measurement is the most common method for taking measurements and is used between edges that are parallel to each other. The baseline method of measuring is strongly suggested when measuring the lo­cation of doors and windows of the house. The fence is located 23 feet from the house and extends to a distance of 63 feet from the house. A separate baseline is used for each side or wall of the house. Regardless of the need or amount of on-site measuring required, it is a task that is best accomplished by the designer and an assistant using a metal or cloth tape measure, preferably 100 feet long. One needs to be acquainted with all these techniques because each serves a different purpose in locating existing site elements. Figure 6-22 shows a row of trees that are not parallel to the house. This method of locating specific points is useful in locating other individual elements such as poles, lights, and utility boxes. If the homeowner does the site measuring, the designer should double-check key measurements to verify their accuracy. The tree is located at 79.5 feet from the house and the prop­erty line is 93.5 feet from the house. The tape measure is simply stretched perpendicularly between the two edges, and the meas­urement is read. Figure 6—19 illustrates the tape measure stretched along the side of the house. To locate these trees, both the southernmost tree and the northernmost tree are first independently measured using the triangulation method. Another example of baseline measuring is to locate where the edges of the driveway cross the property line (Figure 6-20). Although this is not always the case, it is usually best not to permit the homeowner to do the site measuring because of the lack of experience and appreciation for precise measurements. For instance, assume there is a tree on a site that needs to be accurately located (Figure 6-21). placed. Figure 6-20
Example of locating the driveway at the property line. Triangulation is also a good method to use when lines or elements are not paral­lel to each other.