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surveying (engr. gaco)
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Gravity
Terms in this set (95)
probability
defined as the number of times something will probably occur over the range of possible occurrence
errors
is define as the difference between the true value and the measured value of a quantity
mistakes
are inaccuracies in measurement which occur because some is performed by the geodetic engineer with carelessness poor judgment and improper execution
quadrantal bearing
measures between 0 deg to 90 deg. it is always measures from the reference meridian (either from north or south)
whole circle bearing
measures from 0deg to 360 it is measured from north in clockwise direction
compass rule
the correction to be applied in the latitude or departure of any course is to the total correction in latitude or departure of any course is ti the total correction in latitude or departure as the length of the course is to the length of the traverse
transit rule
the correction to be applied in the latitude or departure of any course is to the total correction in latitude or departure as the latitude or departure of that course is to the arithmetical sum of all the latitudes or departures in the traverse without regards to sign
linear error of closure
in any closed traverse there is always an error. no survey is geometrically perfect until proper adjustment are made. for a closed traverse the sum of the north and south latitudes should always be zero
horizontal lane
a straight line tangent to a level surface
level surface
a curved surface every element of which is normal to the plumb line
level line
a line in a level surface
stride
it is composed of two paces
upper plate
the principal subdivision of a transit which carries the telescope is known as
secular variation
a long extremely slow swing of the needle of the compass is
dumpy level
an alidade is almost commonly used in conjunction with a
level surface
every element of which is normal to the plumb line
topographic survey
is a survey made in order to secure important data from which a topographic map could be made
relief
configuration of earths surface
contour
an imaginary line of constant elevation on the ground surface
countor line
a line on the map joining points of the same elevation
contour interval
on a given map successive contour lines represents elevation which differs by a fixed vertical distance called contour interval
hachures
artificial shade lines drawn in the direct of steepest slope for the purpose of representing a relief
saddle
a dip at the junction of two ridges
thalwegs
are the lines where the two sides of valley meet
route surveys
are surveys made for the purpose of locating any buildings,highways,canals, power transmission lines,pipe lines, and other utilities which are constructed for purpose of transportation or communication
surface floats
it is designed to measure surface velocities and should be made light in weight and of a shape as to offer less resistance to floating debris wind eddy currents and other extraneous forces.
sub-surface floats
this is sometimes called a double floats. it consist of a small surface float from which is suspended a second float slightly heavier than water.
rod float
is usually a cylindrical tube of thin, copper or brass 25 mm to 50 mm in diameter.
vein
a relatively thin deposit of mineral between definite boundaries
strike
the line of intersection of the vein with a horizontal plane
dip
the certical angle between the plan of the vein and horizontal plane measured perpendicular to the strike
outcrop
the portion of the vein exposed at the ground surface
drift
an inclined passage driven in a particular direction
simple curve
a circular arc, extending from one tangent to the next
arc basis
degree of curve is the angle at the center subtended by an arc of 20 m
chord basis
degree of curve is the angle subtended by a chord of 20 m in metric system or 100 ft in english system
current meter
an instrument used to measure the velocity of flowing water through rivers of lakes
shrinkage
when an embankment is built,the volume of compacted earth is generally less than its volume before excavation from its original location. the difference is usually defined as
sextant
this instrument is well suited to hydrographic work which could measure angles in any plane . its limb includes on sixth of a circle although the arc is limited to 60 def but this instrument can measure to 120 deg.
zenith
the point where the vertical produced upward,pierces the celestial sphere is called
altitude
it is complement of the zenith distance of a heavenly body
mine survey
a kind of survey used for the purpose of locating workings under the surface of the earth
vertical circles
are great circles passing from the zenith through the star or sun
hour circle
are the great circles through the poles
zenith
the point where the vertical produce upward pierces the celestial sphere
horizon
the great circle on the celestial sphere cut by a plane through the earths center at right angles to the vertical
equator
the great circle of the celestial sphere cut by a plane through the earths center perpendicular to the axis
meridian of an observer
the great circle of the celestial sphere which passes through the poles and the observers zenith
ecliptic
the great circle of the celestial sphere which the sun appear to describe in its annual eastward motion among the stars
equinoxes
...
autmunal equinox
the point where the sun crosses the equator in september
declination
the angular distance from the equator measured on an hour circle through the point
polar distance
is the complement of the declination
altitude
the angular distance below or above the horizon measured on a vertical circle through the point
zenith distance
complement of the altitude
hour angle
the arc of the equator measured from the meridian westward to the hour circle through the point.
nadir
the point where the plumb line of the transit when prolonged downward
celestial sphere
is an imaginary sphere whose center is the center of the earth and whose radius is infinite
superelevation run-off
the length of super elevation development from zero cross-slope to full design super elevation in a circular curve alignment
Surveyors compass
And instrument for determining the horizontal direction of the line with reference to the direction of the magnetic niddle
Compass box
With the circle good waited from 0 to 90 in both directions from the north and south points and usually having the east and west points interchange
sight vanes
Which defines the line of sight in the direction of SN points of the compass box
Magnetic needle
Has the property of pointing a fixed direction namely the magnetic Meridian
Pocket compass
Which is generally held in the hand and bearings are observed used On Reconnaissance or other rough surveys
Surveyors compass
Which is mounted usually an ally tripod or sometimes on a Jacobs stuff a point Stick about 1.5 m long
Transit compass
A compass box similar to the surveyors compass mounted on the upper or venier plate of the engineers transit
Magnetic declination
The angle that a magnetic Meridian makes it through Meridian
Magnetic dip
The vertical angle which the magnetic Needle mixed with the horizontal due to uneven magnetic attraction from the magnetic poles
Isogonic lines
An imaginary lines passing through places having the same magnetic declination
Isoclinic lines
And imaginary line passing through points having the same magnetic dip
Agonic lines
Imaginary line passing through places having a zero declination
quadrantal bearing
Measures between 0° to 90° it is always measured from the reference Meridian either from North or South
Whole circle bearing
Measures from 0° to 360° it is measured from North in clockwise direction
Compass rule
The correction to be applied in the latitude or departure any course it is to the total correction in that it should our departure as the length of the course is to the length of the traverse
transit Rule
The correction to be applied in the latitude or departure of any course is to the total correctin in latitude or departure as the latitude or departure of that course is to the arithmetical sum of all the latitudes or departures in the traverse without regards to sign
linear error of closure
In any closed traverse there is always an error no survey is geometrically perfect until proper adjustments are made for a close traverse the sum of the north and south attitude should always be zero
360
The sum of the deflection angle for the close traverse where"n" the number of the traverse line is
Vertical circles
Are great circles passing from the zenith through the star or sun
hOur circle
Are great circles through the poles
Zenith
The point where the vertical produce upward pierces the celestial sphere
Horizon
The great circle on the celestial sphere cut by a plane to the earth center at right angles to the vertical
Equator
The great circle of the celestial sphere cut by a plane with the earth center perpendicular to the axis
meridian of an observer
The great circle of the celestial sphere which passes through the poles and the observers zenith
ecliptic
The great circle of the celestial sphere which the sun appear to describe its annual eastward motion among the stars
EQUINOXES
The point of intersection of the equator and the ecliptic
Autumnal equinox
The point where the sun crosses the equator in September
Declination
The angular distance from the equator measured on and hour circle through the point
polar distance
Is the complement of the declination
Altitude
The angular distance below or above the horizon measured on the vertical circle through the point
Zenith Distance
Complement of the altitude
hour angle
The arc of that equator measured from the Meridian West Ward to hour circle through the point
nadir
The point where the plumbline of the transit when prolonged downward
Celestial sphere
Is an imaginary sphere who center is the center of the earth and whose radius is infinite
convergency of meridian
Is the meeting of two tangents at each point of different longitude as they recede to the north pole
Angular convergence in seconds
Different in long in seconds X sine middle latitude
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