Consist of stretching a calibrated tape between two points and reading the distance indicated on the tape

use of graduated tape of measuring or laying out horizontal distances

is based on the optical geometry of the instruments employed and is an indirect method of measurement.

Unknown distances may be determined through their relationship with known distances geometrically.

These methods are widely employed in plane table surveys, and in triangulation work

the use of odometer and measuring wheel

Refers to measurement of images on a photograph.

consists of a telescope with two horizontal hairs called stadia hairs and a graduated rod called stadia rod

The bar which is precisely 2 meters long, consists of a rounded steel tube through which runs a thin invar rod. At each end of the frame the target marks are housed. It is mounted horizontally on a tripod and placed perpendicular to the line of sight

a simple device that can be attached to a wheel for purposes of roughly measuring surface distances

Wheel is rolled over the distance to be measured and the number of revolution of the wheel is directly registered by device.

it is a more portable and self-contained measuring device

consists of a small wheel which is attached to rod and handle, and can be pushed by an operator. As the wheel of the device is rolled along a line to be measured, a built-in calibrated recorder automatically gives a distance read out in meters and decimal of a meter

Can be used to determine distances approximately simply by focusing

In using the device, the operator looks through the eyepiece and sight a distant object such as a flag or range pole which defines the other end of a line to be measured

is a curved surface which is at any point perpendicular to the direction of gravity or the plumb line.

is a curved line in a level surface all points of which are normal to the direction of gravity and equidistant from the center of the earth.

is a plane that is tangent to a level surface at a particular point.

a vertical line at any point is a line parallel to the direction of gravity.

is an imaginary surface of the sea which is midway between high and low tides. It is taken as the reference surface to which most ground elevations are referred.

is any convenient level surface coincident or parallel with mean sea level to which elevations of a particular area are referred.

vertical distance above or below mean sea level or any other selected datum.

difference in elevation between two points is the vertical distance between the two level surfaces in which the points lie.

is used to fix the direction of the horizontal line of sight. It is commonly employed method of determining the elevation of points some distance apart by series of set ups of a leveling instrument along a selected route.

is the process of accurately determining the difference in elevation between two intervisible points located at a considerable distance apart and between

makes use of phenomenon that differences in elevation are proportional to differences in the atmospheric pressure.

used to determine differences in elevation between points at designated short measured intervals along an established line to provide data from which a vertical section of the ground surface can be plotted.

This method of leveling is employed in determining by trigonometric computations the difference in elevation between two points from measurements of its horizontal or slope distance and vertical angle between the points.

combines features of direct leveling with those of trigonometric leveling.

Short profiles at right angles to the line of work are usually plotted at regular intervals

method od determining the relative elevations of points in borrow-pit excavations for the purpose of calculating volumes of earthwork

telescope tube permanently fastened to the level bar

simple and useful device for roughly determining differences in elevation.

use in setting of concrete forms, batter boards, and in establishing grades for earthwork.

it has a self-leveling features. It does not use a level vial and its ability to level to level itself depends upon the action of complex pendulum and prism device.

errors are attributed to imperfections in the instruments either from faults in their manufacture of from improper adjustments.

occurs largely due to the limitations of the senses of touch, sight, or hearing of individuals, the skills, training, and teamwork of the members.

due to natural sources

point of more or less permanent character, the location and elevation of which are known

It serves as a point of reference for elevation

is a fixed point or object, often temporary in character, used in leveling where rod is held first for a foresight, then for a backsight

a sight or rod reading taken on a point of known elevation.

is a sight or rod reading taken on a point of unknown elevation or a point whose elevation is to be determined

is the elevation of the line of sight of the telescope when the instrument is leveled.

line to which the direction of all lines of a survey are referred.

north-and-south line passing through the geographical poles of the earth.

refers to the angle between the true meridian and the magnetic meridian

refers to the direction of any line with respect to a given meridian

direction as given by the angle between the meridian and the line, measured in a clockwise direction usually from the south point of the meridian

refers to the angle between a line and the prolongation of the preceding line.

refers to the angles between adjacent lines inside the figures of a close polygon

refers to the series of straight lines connecting a series of established points along the route of the survey