Recording Field Notes

Engineers and surveyors have developed a standard practice for recording surveying information because it is important that the notes be clear, complete and easy to read. Professional surveyors use electronic instruments when every possible. These instruments record the data and down load it to a data collector or computer for post processing and/or use. On electronic instruments the manufacturers of the equipment establish the process and form for collecting and recording the data.

For small projects and when mechanical equipment is used, the traditional field book is still used. The field book is divided into right- and left-hand pages. The left-hand page contains the title, the location, and the data. The right-hand page of the notes is used to record information about the weather, survey party, equipment and describe the location of the bench marks, turning points, creeks, fence or property lines, or other conditions that might influence the design of the structure for which the survey is being made. The location of the benchmark, or starting point, is also described in the notes. A sketch of the general area, showing the location of the beginning and ending stations of the survey, bench marks, ditches, roads, and other landmarks, also is helpful, Figure 15.8.

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FIGURE 15.8. Standard from for field notes.

FIGURE 15.8. Standard from for field notes.

Good surveying practices dictate that the data be checked if at all possible. In differential leveling, the accuracy is checked by "closing the loop." Closing the loop, or just closure, means surveying or measuring back to the beginning. When completing a differential leveling activity, surveying from BM2 to BM1 should find the same difference in elevation as the first leg of the survey from BM1 to BM2. This is rarely the case, however, because some errors are always present in leveling. The amount by which the original BM1 elevation and the BM1 elevation calculated from loop closing fail to agree is called the error of closure. The closing of the survey is conducted following the same procedure as the first leg of the survey. The instrument is picked up and moved, leveled and a backsight is taken on BM2. The survey is completed using the necessary foresights and backsights to survey back to BM1.

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