Topographic Surveys:

The purpose of a Topographic Survey is to gather survey data about the natural and man-made features of the land, as well as its elevations. From this information a three- dimensional map may be prepared. You may prepare the topographic map in the office after collecting the field data surveying instruments or prepare it right away in the field by plane table.

The work usually consists of the following:
1. Establishing horizontal and vertical control that will serve as the framework of the survey

2. Determining enough horizontal location and elevation (usually called side shots) of ground points to provide enough data for plotting when the map is prepared

3. Locating natural and man-made features that may be required by the purpose of the survey

4. Computing distances, angles, and elevations

5. Drawing the topographic map Topographic surveys are commonly identified with horizontal and/or vertical control of third- and lower-order accuracies.

Route Surveys

The term route survey refers to surveys necessary for the location and construction of lines of transportation or communication that continue across country for some distance, such as highways, railroads, open-conduit systems, pipelines, and power lines. Generally, the pre- liminary survey for this work takes the form of a topographic survey.

In the final stage, the work may consist of the following:

1. Locating the center line, usually marked by stakes at 100-ft intervals called stations

2. Determining elevations along and across the center line for plotting profile and cross sections

3. Plotting the profile and cross sections and fixing the grades

4. Computing the volumes of earthwork and preparing a mass diagram

5. Staking out the extremities for cuts and fills

6. Determining drainage areas to be used in the design of ditches and culverts

7. Laying out structures, such as bridges and culverts

8. Locating right-of-way boundaries, as well as staking out fence lines, if necessary Special Surveys As mentioned earlier in this chapter, Special Surveys are conducted for a specific purpose and with a special type of surveying equipment and methods. A brief discussion of some of the special surveys familiar to you follows. Land Surveys

Land Surveys (sometimes called cadastral or property surveys) are conducted to establish the exact location, boundaries, or subdivision of a tract of land in any specified area. This type of survey requires professional registration in all states.