is an imaginary level line that connects points of equal elevation. This is also the most common method of representing the topography of an area.
Contour lines
is taken on a rod held on a point whose elevation is to be determined.
Foresight reading
are used in the maps intended for purposes of navigation to show peaks and hilltops along the cost lines.
resemble contours, but are not drawn with the same degree of accuracy.
Form lines
are a series of short lines drawn in the direction of the slope. It gives a general impression of the
configuration of the ground, but they do not give the actual elevations of the ground surface.
Hachures
In stadia surveying, it is required to determine the elevation of the line of sight
Height of the Instrument
is defined as the length of a step in walking. It may be measured from heel to heel or from toe to
toe.
Pace
consists of counting the number of steps or paces in a required distance
Pacing
is the science of mapping out a big tract of land and consist in taking overlapping photographs
from airplane flown at adequate altitudes.
Photogrammetry
An instrument or device used to determine the area of any irregular figure plotted on a map that is drawn to scale.
Planimeter
refers to a geographical feature where two adjacent hilltops or ridges slope downward on both sides, creating a low point or dip between them. This low point resembles the shape of a saddle, hence the term.
Saddle
provides a rapid means of determining distances. The equipment for stadia measurement consists of a telescope with two horizontal hairs called stadia hairs and a graduated rod called a stadia rod.
Stadia Method
is another procedure of obtaining horizontal distances. It is based on the optical geometry
of the instruments employed and is an indirect method of measurement.
Tachymetry (or tacheometry)
is the method of measuring or laying out horizontal distances by stretching a calibrated tape between two points and reading the distance indicated on the tape.
Taping
It refers to the line of lowest elevation within a valley or watercourse, which typically represents the path of
a river or stream’s current
Thalwegs
is the correction to be applied to the latitude or departure of any course is to be the total error of latitude or departure as the length of the course is to the length of the traverse is one way of balancing a traverse.
Transit rule
a point where the vertical produce upward, pierces the celestial sphere.
Zenith
