Civil Engineering Reference
In-Depth Information
Chapter 2
Getting Started
2.1 Land Surveying Types
A broad definition of land surveying is that surveyors make measurements on or
near the surface of the earth. These measurements have traditionally consisted of
angles and distances made using optical surveying instruments. Global Navigation
Satellite Systems (GNSS or GPS), which use signals emitted by satellites to fix
locations on the earth, are supplementing, or in some cases even replacing, tradi-
tional techniques and equipment.
Land Surveying can be grouped into several general classifications, such as
boundary surveying, topographic surveying, construction surveying, and control
surveying. Topographic surveys deal with physical features found at a site and the
elevation of the earth's surface. A topographic plan will commonly show build-
ings, fences, shorelines, sewers and utilities. Topographic plans show contour lines
which depict the ground elevations at the site (Fig.
2.1
). These plans are often used
by developers, engineers and architects for the design and siting of roads, build-
ings and other structures.
Construction surveys establish control and layout for road and highway lay-
outs, bridges, buildings, sewers and other man-made improvements. Hydrographic
surveys are made to acquire data on water depths, locations of rocks, sandbars,
coastline erosion and other features associated with oceans, bays, harbors, lakes or
rivers.
Control surveying is used to establish precise networks of control points for fix-
ing horizontal and vertical positions. After the control points are established, they
can be used for other types of survey projects such as topographic, boundary, route
layout and mapping surveys. Control surveys were originally performed using
