facts - ES Flashcards by ruby nunns

how to convert degree minutes seconds to degrees

divide minutes by 60 and seconds by 3600 and add to the degrees

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how to convert gons/ gradians to degrees

x 180/200 or x 9/10

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360 degrees = ____ radians

2*pi

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list elements of engineering surveying (max 6)

investigate land
producing plans for design
on-site 3D construction (setting out)
monitoring the construction process
recording the final ‘as-built’ position
providing control points to monitor structural movements

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what is the standard area units (other than m^2)

how does this convert to m^2

hectares

1 hectare = 10,000m^2

or acre = 100m^2 (since hec- =100)

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calculator conversion functions for:

dms to degrees
polar to rectangular and vice versa

button with symbols on it (after each value - INLCUDE zeros)

Pol and Rec (bottom right) via shift key and use shift comma (bracket button) between

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how is leveling used

vertical control systems
setting out
contouring
alignment in designs

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if the error is less than 1 mm per 20m, _________. However if the error is _________, ____________.

don’t adjust the instrument

greater than 1mm per 20m, adjust the instrument (check the compensator)

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Vertical angles above the horizontal plane are said to be _____, and those below ______.

elevation

depression

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radians to seconds

x206265

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What are fiberglass tapes made of

fiberglass strands embedded in PVC

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Properties of fiberglass tapes

stretchy, light, flexible

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List some key properties of steel tapes

fragile/ brittle
must be kept dry

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What is the composition of a steel tape

steel protected by coats of polyester or nylon

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steel tapes are calibrated _____________________.

at a specific temperature and tension

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phase measurements are used for distance between ______ and ____. Timed pulse is used for __________.

200m and 300m, distance up to 2000m

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is accurate alignment necessary in EDM?

no, only ±10% incidence needed

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what is a control network? when is this completed?

a circuit of control points/ stations of known height/ TBMs if necessary which link together as a network

before surveying commences

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what are the three types of control network

horizontal (rectangular co-ordinates based on grid with origin)

vertical (points defined relative to a datum

combined

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which type(s) or north are typically used and not used in surveying

NOT true north

magnetic north (prismatic compass) or arbitrary north (assigned for good grid alignment)

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what are the conventions of whole circle bearings

3 figures
measured clockwise from north

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misclosure tolerance for control traverses

±30*sqrt(n)
n = no. of stations

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advantages of terrestrial laser scanning

creates digital terrain models (DTMs)
non-contact (limited site disruption)
independent of daylight
high precision and accuracy

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disadvantages of terrestrial laser scanning

line of sight dependent
laser diverges at long ranges
dark/ reflective features difficult to map
high power input required

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what are the two main aims of setting out

check the construction is correct in all 3 dimensions avoid delays in construction

what are the 4 types of grids in setting out

survey site structural secondary

what is the distinguishable difference between first and second stage setting out

1st - substructure 2nd - superstructure

List the steps in first stage setting out

define site set foundations fix ground floor levels locate embankments and cuttings

What is involved in second stage setting out

establishing above ground elements (vertical controls)

to what accuracy can optical plummeting devices be

1: 200,000

what are the two different types of lasers and two different instrument types

invisible and visible rotating and alignment

invisible lasers are _____ power and use ___________ wavelengths of approximately _______nm.

low infra-red 780

visible lasers are usually _____ or ______ and have corresponding wavelengths of _____ and _____.

red green 640nm 530nm

how are visible lasers intercepted and received

eye/ plain sight plastic targets photoelectric detectors

lasers are classified into ____ safety categories. the higher the number, the _____ the potential hazard

7 greater

what range of power are lasers typically

1-5mW

class 1 lasers are ____________ to the human eye and are commonly used in ________________________.

completely safe, barcode scanners

class 2 lasers are safe due to ____________. These are what are most commonly used for ___________________________.

blink reflex pipe lasers, laser plummets, visible beam levelling and grading lasers

You should avoid looking in lasers of class _________. 3__ can be viewed in a dull reflection but 3__ (tunnel lasers) only through ____________________.

3 and above 3B 3R (pipe lasers) magnifying optics

laser theodolites have an approximate visibility of ____________ and use lasers of classes _________.

200-600m, 1-3R

precision laser plummets can be used for heights above ______ and utilise class ___ lasers. they are targeted onto _________ and include an automatic _________________.

100m 2 plastic grids levelling system

what accuracy do precision laser plummets have

±2.5mm in 100m or 1 in 40,000

what are the main benefits of pipe lasers (4)

remotely controllable 100% waterproof self level ±5% removes need for sight rails and travellers

what class(es) are tunnel lasers typically

2 or 3R

what is the distance range and accuracy of rotating lasers

30-400m ±2-5mm per 100m

to what accuracy do rotating lasers self-level

±10%

the earth is a....

rotating ellipsoid

the central meridian/ true origin in OS maps is

2° west, 49° north

where is the false origin and why is it used

400km west and 100km north of the true origin essentially to avoid negative values

why does the scale of the map change

curvature as proceed further from the centre

Between the central meridian and the sub-parallels either side, the SF is _______________.

less than 1

if F ________ than 1, the ellipsoid distance is ____________ than the national grid distance.

greater than, shorter

what is the most common GNSS system

Navstar GPS

what was GNSS originally used for

military applications

GNSS uses _________ signals which take approximately ____ms to be received

radio wave 70

the GPS segment compromises 3 elements. list them

space segment control segment user's receiver system

how far away from earth are GPS satellites located

approx. 20,200km

Each satellite carries 4 ____________.

atomic clocks

The GPS space segment consists of a minimum of ____ satellites

Scales for a longitudinal sectional (H and V)

H 1:500 V 1:100

Scales for a cross-sections (H and V)

H 1:200 V 1:50

control traverses FLM aim

1:10,000

when setting out sewer pipes, how frequently should manhole covers be placed

every 100m

invisible beam leveling lasers are usually class ___.

facts - ES Flashcards

(64 cards)