MODULE 2 CE101

Angles measured are classified as either ______ or _______

In surveying, directions are given by ________ and _______.

Based on degrees, minutes, and seconds

Based on gradians

based on radians

based on milliradians

Direction of Lines Conversion

The direction of a line is defined by a horizontal angle between the line and an arbitrarychosen reference line called a ______.

Types of Meridians:

north-southreference line that passes through amean position of the Earth’sgeographic poles.

defined by a freelysuspended needle that is onlyinfluenced by the Earth’s magneticfield.

a fixed line of referenceparallel to the central meridian of asystem of plane rectangularcoordinates.

established by merelyassigning any arbitrary direction.

north point of the true meridian.

established by means of a magnetic compass needle when there are nolocal attractions affecting it.

north point which is established by lines on map which are parallel to aselected central meridian.

used to portray the location of any arbitrary chosen north point.

the acute horizontal anglebetween a reference meridian andthe line

observed from either north orsouth toward the east or west.

horizontal angles observedclockwise from any referencemeridian

horizontal angle observed from geodetic meridian to the magnetic meridian.

Magnetic Declination is also called _____________ of the compass

Types of variation:

slow gradual, but unexplainable shift in the position of the Earth’smagnetic meridian over regular cycle.

also called as ________. It is an oscillation of the compass needles through a cycle from its mean position over a 24 hour period.

periodic swing which is less than 1min of an arc and can be neglected.

unpredictable magnetic disturbances and storms can cause short-term irregular variations of a degree or more.

basic observations needed for determining the direction of lines.

horizontal angle that the line makes with an established line ofreference.

Horizontal angles most commonly observed in surveying are:

angles between adjacent lines in a closed polygon.

- measured clockwise or counterclockwise

Interior Angle formula

located outside a closed polygon and are referred to as explements ofinterior angles

- the sum of interior and exterior angles at any station is equal to 360°.

measured clockwise from the rear to the forward station and can beeither interior or exterior angles of a closed traverse.

angle between a line and the propagation of the preceding line.

- positive for clockwise, negative for counterclockwise

- always less than 180

series of lines connecting successive points whose length and directions havebeen determined from field measurements.

process of measuring lengths and directions of the lines of a traverse for thepurpose of locating the position of certain points.

any temporary or permanent point of reference over which theinstrument is set up. It is usually marked by a peg or a hub. Also called angle points because an angle is usually measured at such stations.

lines connecting traverse stations and whose lengths and directions are determined.

is used principally in land surveying. The usual practice inmeasuring interior angles is in clockwise direction.

is employed when numerous details are to be located from thetraverse station. It is measured clockwise from the back line to the forward line.

is used frequently for location survey of roads and other similarsurveys. The horizontal angle is measured clockwise (positive) and counter clockwise(negative).

is measured clockwise either from the north or south end of a selected reference meridian to the line.

Is one of the most basic and widely accepted practiced method ofdetermining the relative location of points where a high degree if precision is required.

Types of Compass Surveys:

consists of a series of lines of known lengths andmagnetic bearings which are continuous but do not return to the startingpoint or close upon a point of known position.

consists of a series of lines of known lengths andmagnetic bearings which forms a closed loop, or begin and end at pointswhose positions have been fixed by other surveys of higher precision.

line projection onto the reference meridian or north-south line

line projection onto the reference east-west line.

The procedure for computing the linear error of closure and applying corrections to theindividual latitudes and departures is referred to as________ ________.

Methods of adjusting traverse:

Is based on the assumption that all lengths were measured with equal careand all angles were taken with approximately the same precision.

is based on the assumption that all angular measurements are more precisethan the linear measurements.