Surveying

Electronic Distance Measurement

(EDM)

the surface of a large body of water at rest.

A level surface is best visualized as being...

Baseline

A line of reference for survey work

Meridian

A line on the mean surface of the joining the north and south poles

Benchmark

A permanent point of known elevation.

Turning Point

A point temporarily used to transfer an elevation

Backsight

A rod reading on a point of a known elevation to establish the elevation of the instrument line of sight.

Foresight

A rod reading taken on a turning point, benchmark, or temporary benchmark to determine its elevations

Temporary Benchmark

A semi-permanent point of known elevation

Culvert

A structure designed to provide an opening under a road or other feature, usually for transportation of storm water

Geodetic Surveying

A survey of such high precision or covering such a large geographical area that computations must be based on the ellipsoidal shape of the earth.

Property Surveys

A survey to retrace or establish property lines, or to establish location of buildings within property limits.

Automatic Level

A surveyor's level in which line of sight is maintained automatically in the horizontal plane, once the instrument is roughly leveled.

Active Control Station

ACS

Horizontal directions

All _____ are referenced to meridians

Absolute Positioning

Also called point positioning

Digital Level

An automatic level (pendulum compensator) capable of normal optical leveling with a rod graduated in feet or meters

Benchmark

BM

Backsight

BS

Bearing Angles

Can be measured clockwise or counterclockwise, is always accompanied by the letters that locate the quadrant in which the line falls (NE, NW, SE, SW)

Fiberglass Tapes

Can give accuracies in the half-centimeter range

Steel Tapes

Can measure to the nearest hundredths of a foor or the nearest millimeter

Control Surveys Preliminary Surveys Layout Surveys

Classes of Surveys

Surveyor's Level

Consists of crosshair-equipped telescope and an attached circular bubble, or spirit level tube, all of which are mounted on a sturdy tripod.

problems that become apparent only after construction is underway.

Design changes result from

Differential Leveling

Determining the difference in elevation between points using a surveyor's level.

Pacing Odometer Electronic Distance Measurement (EDM)

Distance Measuring Techniques

1. Leveling techniques 2. Total station techniques 3. GPS vertical positioning techniques 4. Remote-sensing techniques

Elevations can be determined using:

Foresight

FS

As-Built Drawing

Final plan

EDM instruments

Function by sending a light wave or microwave along the path to be measured

meridians of longitude

Geographic meridian is also known as

1. To refer to a proposed elevation 2. To refer to the slope of a profile line 3. To refer to cuts and fills

Grade meanings:

1. Ease of calculation (plane geometry and trigonometry) 2. The availability of one common datum for X and Y dimensions in a large (thousands of square miles) area

Grid Reference Advantages

Central Meridian

Grid reference meridian

Height of Instrument

HI

Drag Tapes

Heavy Duty Steel Tapes

theodolite or total station

Horizontal angles are usually measured with _____whose precision usually ranges from 1 to 20 seconds of arc

Intermediate Sight

IS

Vertical Line

Line from the surface of the earth to the earth's center. It is also referred to as a plumb line or line of gravity

Level Line

Line in a level surface

Grid Meridians

Lines that are parallel to a grid reference meridian (central meridian)

Mean Seal Level

MSL

Geographic Meridian

Meridian is known as

Total stations or other EDM devices

Most distances are now measured using..

Plane Surveying

Most engineering and property surveys

Stadia

Obsolete form of indirect measurement that uses a cross hair configuration to assist in determining distances.

partial payments completion and acceptance of the project

On most construction projects, ______ are made to the contractor at regular intervals, and final payment is made upon _____

Magnetic Meridians

Parallel to the directions taken by freely moving magnetized needles, as in a compass

the project inspector and the construction surveyor

Payments are based on data supplied by

Final ("as-built") Surveys

Post construction survey that confirms design execution and records in-progress revisions.

Aerial Surveys

Preliminary and final survey using traditional aerial photography and aerial imagery.

Topographic Surveys

Preliminary survey used to tie in the horizontal and vertical positions of natural and constructed surface features of an area.

Route Surveys

Preliminary, control, or construction surveys that cover a long but narrow area, as in highway and railroad construction.

Azimuths

Range in magnitude from 0-360 degrees

Construction surveyor

Records items that require a surveying function (excavation quantities, concrete placed in structures, placement of sod)

Project inspector

Records items, such as daily progress, staff, and equipment in used, and materials used.

Intermediate Sight

Rod reading taken at any other point where the elevation is required

100 ft

Steel tape length that is most commonly used

Horizontal Line

Straight line perpendicular to a vertical line

Layout Surveys

Survey in which they surveyor marks on the ground the features shown on a design plan.

Plane Surveying

Survey of such limited size that computations can be based on plane geometry and trigonometry for all horizontal positioning.

Control Surveys

Survey taken to establish or reestablish reference points, elevations, and lines for preliminary and construction surveys.

Hydrographic Surveys

Surveys designed to define shoreline and underwater features.

Construction Surveys

Surveys that provide line and grade.

Temporary Benchmark

TBM

Turning Point

TP

Tilting Level

The (mostly obsolete) tilting level is roughly leveled by observing the bubble in the circular spirt level.

Surveying

The art and science of measuring distances, angles, and positions, on or near the surface of the earth.

accuracy

The conformity of a measurement to the "true" value

Azimuths

The direction of a line a given by an angle measured clockwise (usually) from the north end of the meridian.

Height of Instrument

The elevation of the line of sigh through the level

revisions are made during the construction process.

The final plan, known as the as-built drawing, is usually quite similar to the design plan, with the exception that...

relocate the horizontal and vertical control used in the preliminary survey

The first on-site job for the construction surveyor is to:

Preliminary Surveys

The gathering of data (distance, position, an dangles) to locate physical features, so that they can plotted to scale on a map or a plane.

Leveling

The procedure for determining differences in elevation between points that are some distance from each other.

Elevation

The vertical distance above or below a given datum; also known as orthometric height.

Mean Sea Level (MSL)

Traditional vertical reference datum

1. Land surveying (boundary or property surveying) 2. Engineering surveying

Two Largest fields of surveying

Heavy Duty - 5/16" x 0.18" (8mm x 0.45mm) Normal Usage - ¼" x 0.012" (6mm x 0.30mm)

Two cross-sections of steel tapes

Automatic Level Digital Level Tilting Level

Types of Surveying Levels

Plane Surveying Geodetic Surveying

Types of Surveys

Steel Tapes

Used for precise tape measuring

Taping

Used for short distances and in many construction applications

System of Geographic Coordinates

Used in navigation and geodesy, but those engaged in plane surveying normally use their coordinate grid systems or the original township fabric as a basis for referencing

Fiberglass Tapes

Used when lower precision is acceptable

Steel Tapes

Were used in route surveys and are designed for use off the reel

Angles in the horizontal and vertical planes

What angles so surveyors measure?

Horizontal, slope, and vertical

What distances do surveyors measure?

Take and analyze measurement

What do surveyors do?

Distances, angles, and positions

What do surveyors measure?

1. Two-dimensional points 2. Elevation dimensions referenced to mean sea level (MSL) 3. Three-dimensional positions of points

What positions do surveyors measure?

North America - Must be licensed by the state or province in which they work Engineer Surveyors - must have a civil engineering license

Who can perform surveys?

Benchmark

______ are established by using precise leveling techniques and instrumentation.

Temporary Benchmark

______ can be flange bolts on fire hydrants, nails in the roots of trees, top corners of concrete culvert headwalks, and so on

Benchmark

______ elevations and locations are published by federal, state or provincial, and municipal agencies, and are available to surveyors for a nominal fee.

Temporary Benchmark

______ elevations are not normally published, but they are available in the field notes of various surveying agencies.

Latitude

east/ west, parallel to the equator, measured 90 max

Level Surface

is a curved surface parallel to the mean surface of the earth.

Longitude

north/south, perpendicular, measure 180 max