Measurement of Angles and Directions Flashcards
Usually defined by the horizontal angle it makes with a fixed
reference line or direction
Direction of a Line
4 TYPES OF MERIDIANS
Generally adapted reference line in surveying practice.
True Meridian
4 TYPES OF MERIDIANS
Passes through the geographic north and south poles of the earth
and the observer’s position
True Meridian
4 TYPES OF MERIDIAN
True Meridian is sometimes also known as?
Astronomic or Geographic Meridian
4 TYPES OF MERIDIAN
A fixed line of reference which lies parallel with the magnetic lines of force of the earth.
Magnetic Meridian
4 TYPES OF MERIDIAN
Its direction is defined by a freely suspended magnetic needle of a compass held at the observer’s position
Magnetic Meridian
4 TYPES OF MERIDIAN
A fixed line of reference parallel to the central meridian of a system of plane rectangular coordinates.
Grid Meridian
4 TYPES OF MERIDIAN
An arbitrarily chosen fixed line of reference which is taken for convenience.
Assumed Meridian
4 TYPES OF MERIDIAN
Usually the direction from a survey station to an adjoining station or some well-defined and permanent point.
Assumed Meridian
UNITS OF ANGULAR MEASUREMENT
The sexagesimal system is used in which the circumference of a circle is divided into 360°.
Degree
UNITS OF ANGULAR MEASUREMENT
The angle of 1° is defined as the angle which requires 1/360 of the rotation needed to obtain one complete revolution.
Degree
UNITS OF ANGULAR MEASUREMENT
The unit of measure in the centesimal system.
Grad
UNITS OF ANGULAR MEASUREMENT
The circumference of a circle is divided into 400 _______.
Grad
UNITS OF ANGULAR MEASUREMENT
It is divided into 100 centesimal minutes and a centesimal minute is further divided into 100 centesimal seconds.
Grad
UNITS OF ANGULAR MEASUREMENT
The circumference is divided into 6400 mils, or 1600 mils is equal to 90°.
Mil
UNITS OF ANGULAR MEASUREMENT
It is commonly used in military operations as in fire direction of artillery units.
Mil
UNITS OF ANGULAR MEASUREMENT
Defined as the angle subtended at the center of the circle by an arc length exactly equal to the radius of the circle.
Radian
UNITS OF ANGULAR MEASUREMENT
It is used in computations such as determining the length of circular arcs and where high speed electronic digital computers are used.
Radian
1 Radian is equal to how much in degrees?
180°/π or 57.2958°
1 Degree is equal to how much in radian?
π/180° or 0.0174533 radian
