Civil Engineering Survey Review, 3ed
Including many examples and problems with solutions, this detailed guide will help to prepare for the Special Civil Engineer (CE) Exam which is required for all civil engineer examinees.
TABLE OF CONTENTS Civil Engineering Survey Review, 3ed
Chapter 5: Topographic Survey
Overview
Topographic survey is the determination of the location of objects on the surface of the earth. It may be done by aerial or ground method. The first requirement of topographic survey is a good control survey.
The Federal Geodetic Control Committee (FGCC) establishes the following orders of control accuracy in 1974.
| Order | Closure in length | Principal uses |
|---|---|---|
| First-order | 1 part in 100,000 | National Control Netwok (Primary Control) |
| Second-order | ||
| Class I | 1 part in 50,000 | High-value land areas (Secondary Control) |
| Class II | 1 part in 20,000 | Lightly developed areas (Supplemental Control) |
| Third-order | ||
| Class I | 1 part in 10,000 | Local construction |
| Class II | 1 part in 5,000 | (Local Control) |
| Order | Maximum | Closure | Principal uses |
|---|---|---|---|
| First-order | |||
| Class I | 3 mm | | Basic Net A |
| Class II | 4 mm | | Basic Net B (Basic Framework) |
| Second-order | |||
| Class I | 6 mm | | Metropolitan areas (Secondary Network) |
| Class II | 8 mm | | Local project (General Area Control) |
| Third-order | 12 mm | | (Local Control) |
where K is the distance between Bench Marks in Kilometers
There are two types of control surveys: Horizontal and Vertical. Horizontal control may be done by triangulation, traverse, or trilateration survey. For small areas, traverses furnish satisfactory control. For large areas, such as over a state, triangulation or trilateration furnishes the most economical horizontal control. Vertical control may be done by barometric, trigonometric, or differential leveling. The required accuracy for a control survey depends on its purpose.
Cartography...
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