Chapter 1 Basics of Surveying

What are two applications of surveying? (NOT covered in lecture, from textbook ppt)

1) Measure the location of ground features to prepare a map or plan of the area 2) Locate design features in the field by distance, angle, and/or positioning measurements shown on a map or plan

Name 3 classes of surveys

1. Preliminary Survey (data gathering) 2. Layout Survey 3. Control Survey

Name 3 types of COMBINED preliminary, layout, and control surveys

1. Route surveys 2. Cadastral/ Property/Land surveys 3. Aerial surveys

Right-angle offset tie

Point P is located relative to known line AB by determining CB or CA, the right angle at C, and distance CP

Hydrographic Surveys

Refers to the surveying of bodies of water for navigation, water supply, or subaqueous construction purposes Used to tie in underwater features to surface control points. Usually of shorelines, marine features, and water depths.

What are the benefits of using satellite positioning receivers in surveying?

Satellite positioning provides positions with much greater speed, accuracy and economy.

What types of surveys do not have high accuracy as a prime requirement and what data collection methods can you use then?

Some geographic information systems (GISs) surveys and many mapping surveys do not have as a prime requirement high accuracy. In these cases, data can be efficiently collected from less precise satellite positioning receivers and, as well, from satellite and airborne imaging platform.

How has advanced technology affected the collection of data during surveying?

Survey data once laboriously collected with tapes, transits, and levels (recorded manually in field books) can now be quickly and efficiently collected using total stations and precise satellite positioning receivers.

Theoretically correct location

Determined from repeated measurements or mathematical analysis.

Simple dimensions in stationing (offset distances)

Distances at right angles to the baseline established with stationing.

Route Surveys

Linear construction surveying Surveys that range over a narrow but long strip of land. Typical projects that require route surveys are lines of transport (highways, railroads, canal, pipelines) or communication (electricity transmission lines, and channels)

What are some benefits of design software?

Once the coordinates of all field data have been determined, the design software can then compute the coordinates of all key points for the surveyor perform a construction layout survey in the field showing the contractor how much cut and fill (for example) is required to bring the land to the proposed elevations and locations. Additionally, the design data can be transferred to construction machine controllers for machine guidance and control functions in heavy engineering projects.

What are the two main types of surveying ?

Plane and Geodetic surveying

Mistakes

Mistakes are blunders made by the survey personnel. Examples of mistakes include transposing figures (recording a tape value of 68 as 86), miscounting the number of full tape lengths in a long measurement, measuring from the wrong point and so on.

Plane surveying

Most common survey done. Assumes the surface being surveyed is flat and horizontal (except for leveling) Earth surface considered - plain Line formed by joining any two points are considered as the same angles are plain Suitable for small area surveying Survey accuracy - low Method - Economical and easy survey method

Error of closure

The difference between the measured location and the theoretically correct location. The error of closure will be composed of random errors BECAUSE relevant systematic errors and mistakes can and should be eliminated from all survey measurements,

Transit:

An optical instrument or telescope, complete with a built-in spirit level that is mounted on a tripod

What angles do surveyors measure?

Angles in the horizontal and vertical planes.

As a rule, why is it important for a surveyor to immediately check and repeat measurements?

**IMPORTANT: As a rule, every measurement is immediately checked and repeated. (This immediate repetition enables the surveyor to eliminate most mistakes and, at the same time, improve the precision of the measurement)

Name 4 types of Surveying References

1) Geographic reference 2) Grid reference 3) Legal reference 4) Vertical reference

Photogrammetric Surveys

Aerial photographs used to locate positions and distances

What are the two largest fields of surveying?

Boundary/property surveying and engineering surveying.

How must Field notes be recorded?

Field notes must be recorded: Neatly Accurately and honestly Legibly Clearly Self Explanatory and self checking

What must field notes include?

Field notes should include the following information: • Type and description of survey - Title • Location of survey • Date of survey • Party members • Weather conditions • Equipment used - type and number • Sketches or remarks Right hand side of page • Sketches always show a north arrow • Tabulated values and field data Left hand side of page

Layout surveys

Involve marking on the ground (using wood stakes, spikes, etc.) the features shown on a design plan. The layout could be for property lines, foundations, roads, pipelines, bridges, etc. Data will also be given for the proposed design elevations which are referenced to sea level.

What distances do surveyors measure?

Horizontal distances, slope distances, and vertical distances.

What do surveyors do?

Take and analyze measurements.

Satellite positioning receiver.

Captures signals transmitted by four or more positioning satellites to determine position coordinates (e.g., northing, easting, and elevation) of a survey station.

GLONAS

The Russian satellite positioning system

Global positioning system (GPS)

The U.S. NAVSTAR positioning system

Precision

The ability to repeat the same measurement with consistently small variations only NOTE: a more precise method will result in the more accurate measurement, but precise methods can also be inaccurate because random errors from the surveyor can lower precision.

What does the accuracy and thus reliability of the survey depend on?

The accuracy, and thus reliability, of the survey depends the surveyor's field expertise and understanding of the scientific principles underlying and affecting all forms of survey measurement.

Surveying

The art and science of measuring distances, angles, and positions (northing, easting, and elevation), on OR near the surface of the earth. Rigorous mathematical techniques are used to analyze and adjust the field survey data.

Why is a survey grid reference limited in size?

The grid is limited in size so that no serious errors will accumulate when the curvature of the earth is ignored.

Accuracy

The relationship between the value of a measurement and the "true" value

Geodetic Reference System (GRS80).

Three-dimensional positions of points on or near the earth's surface referenced to a defined ellipsoidal model of the earth

Name 7 types and subtypes of Surveying Fields

Type of layout survey · Construction surveys: for engineering works Types of preliminary surveys · Topographic surveys: · Hydrographic surveys: Similar to preliminary surveys · Final ("as-built") surveys: Types of combined preliminary, layout, and control surveys · Route surveys · Property surveys · Aerial surveys

Galileo

The European Union satellite positioning system

Global Navigation Satellite System (GNSS)

A term used world-wide to describe the various satellite positioning systems now in use, or in various stages of implementation and planning.

Legal description of property

A way to accurately locate and define a particular piece of property

What is the most used vertical reference in surveying?

Although vertical dimensions can be referenced to any datum, the reference datum most used is that of mean sea level (MSL).

1.8 Describe the term error; how does this term differ from mistake?

An error is any difference between the true value and the measured value. A mistake is one type of error that is caused by human blunders.

Total station

An instrument that combines electronic distance measurement (EDM) with an electronic theodolite. The highly sensitive electronic bubbles along with laser plummets allow this total station to be set precisely over a point

Theodolites

An instrument using photoelectric sensors that measures horizontal and vertical angles and establishes linear and curved alignments in the field. Laser plummets are used to center the instrument over the station mark.

1.5 Describe an integrated survey system (geomatics data model).

An intergrated survey data system is a geomatic data model which shows each branch and specialization tied together with a common factor of measuring earth data using computer science and information technology. Field surveying and remote sensing is done and the databases are entered and processed by a computer in order to plot the geodata into plans and maps.

What must bound books for field notes have?

Bound Field Books must have: 1. Name, address, e-mail address, and phone number should be in ink on the outside cover. 2. Pages should be numbered consecutively throughout. 3. Space is reserved at the front of the field book for title, index, and diary. 4. Each project must show the date, title, surveyors' names, and instrument identification numbers.

Permanent point

Elevations that have been precisely determined (benchmarks) are available in most areas for survey use.

Systematic errors

Errors whose magnitude and algebraic sign can be determined. The fact that these errors can be determined allows the surveyor to eliminate them from the measurements and thus improve the accuracy. An error from the effects of temperature on a steel tape is an example of a systematic error. If the temperature is known, the shortening or lengthening effects on a steel tape can be precisely determined.

Control Surveys

Establish a network of horizontal and vertical monuments The network can be used as a reference framework for other surveys

Control surveys

Establishes a network of precise locations of horizontal and vertical monuments/positions that serve as a reference framework of which preliminary and layout surveys can be based on

What is the standards of how field notes must be done?

Field Notes 1. Entries are to be in pencil in the range 2H to 4H. The harder pencil (4H) is more difficult to use but will not smear. The softer pencil (2H) is easy to use for most people but will smear somewhat if care is not exercised. Most surveyors use 2H or 3H lead. Pencils softer than 2H are not used in field notes. 2. All entries should be neatly printed. Uppercase lettering can be reserved for emphasis, or it is sometimes used throughout. 3. All arithmetic computations are to be checked and signed. 4. Sketches are used to clarify the field notes. Although the sketches are not scale drawings, they are usually drawn roughly to scale to help order the inclusion of details. 5. Sketches are not freehand. Straightedges and curve templates are used for all line work. 6. Sketches should be properly oriented by the inclusion of a north arrow (preferably pointing up the page or to the left). 7. Avoid crowding the information onto the page. This practice is one of the chief causes of poor-looking notes. 8. Mistakes in the entry of measured data are to be carefully lined out, not erased. 9. Mistakes in entries other than measured data (e.g., descriptions, sums, or products of measured data) may be erased and reentered neatly. 10. Show the word "COPY" at the top of copied pages. 11. Lettering on sketches is to be read from the bottom of the page or from the right side. 12. Measured data are to be entered in the field notes at the time the measurements are taken. 13. The notekeeper verifies all data by repeating them aloud as he or she is entering them in the notes. The surveyor who originally gave the data to the notekeeper will listen and respond to the verification call-out. 14. If the data on an entire page are to be voided, the word "VOID," together with a diagonal line, is placed on the page. A reference page number is shown for the location of the new data.

Preliminary surveys (data gathering)

Gathers geospatial data (distances, positions, and angles) to locate physical features so that the data can be plotted to scale on a map or plan. Differences in elevation (vertical distances) are also determined so elevations and contours may also be plotted. Example: Digital Terrain Model (DTM) represents elevation data of terrain. Physical features include water boundaries, trees, roads, structures, or property markers, manholes, etc.

Why do surveyors still use handwritten field notes despite the availability of advanced technology?

Hand-written field notes can be very useful to 1. Describe key points and/or a sampling of point positioning data 2. Field notes are invaluable as a check on critical aspects of the fieldwork, and as an aid in the data editing that always occurs in the data processing stage of an electronic survey.

How were legal descriptions of properties created in North America?

Historically public lands in North America were originally laid out for agricultural use by the settlers. 1. Lands divided into townships In the United States and Canada, the townships were laid out in 6-mile-square (and contain 36 square sections). The townships were subdivided into sections and ranges (lots and concessions), each uniquely numbered. 2. Townships divided into sections or lots Each basic township section or lot were 1 mile square (Easy to remember because in each township of 6 mile square there are 36 square sections of which each section is 1 mile square). 3. Sections or lots subdivided into real estate developments The sections are then further subdivided in real estate developments and this is how legal descriptions of properties are created.

MSL (mean sea level)

MSL is assigned an elevation of 0.000 feet (ft) (or meters), and all other points on the earth are usually described as being elevations above or below zero.

What are the coordinates in most grid systems referenced to and why?

The coordinates in most grid systems can be referenced to a zone's central meridian and to the equator so that translation to geographic coordinates is always accomplished.

Name 8 specialized surveys

1. Cadastral Surveys 2. Control Surveys 3. Hydrographic Surveys 4. Engineering and Construction Surveys 5. Mine or underground Surveys 6. Photogrammetric Surveys 7. Route Surveys 8. Topographic surveys

Name 7 types of instruments most commonly used in field surveying?

1. Satellite positioning receiver, GPS (Global Positioning Satellites) 2. Robotic total station (combines EDM with electronic theodolite) 3. Level and rod - determine elevation 4. Theodolite 5. Steel tape - chain 6. Transit 7. EDM (Electronic Distance Measurement)

What positions do surveyors measure?

1. The two-dimensional positions of points on or near the surface of the earth referenced to a defined Cartesian grid or to a geographic grid (latitude and longitude) 2. Elevation dimensions referenced to mean sea level (MSL) 3. Three-dimensional positions of points on or near the earth's surface referenced to a defined ellipsoidal model of the earth called the Geodetic Reference System (GRS80).

Name 2 types of preliminary surveys

1. Topographic surveys: 2. Hydrographic surveys

What is the main purpose of surveying efforts?

A lot of surveying effort is to measure points of interest relative to some reference line so that these points may be shown on a scaled plan.

Name a type of layout survey Similar to preliminary surveys Final ("as-built") surveys: ties in just been constructed features for a final record of the construction and to check that the construction has proceeded according to the design plans.

Construction surveys: for engineering works

Topographic surveys

Contours of land surface both natural and unnatural Used to locate and map the natural and manmade surface features of an area. The features are located relative to one another by tying them all into the same control lines or control grid.

What types of surveys usually require high accuracy?

Control surveys, engineering surveys, and land surveys

Mine or underground Surveys

Control, locate, and map underground and surface works related to mining operations

What do surveyors measure?

Distances, angles, and positions.

1.4 (assigned question) How is a total station different from an electronic theodolite?

Electronic theodolites are less expensive and less precise instruments compared to a total station. Theodolites only measure horizontal and vertical angles. Theodolites are comprised of a telescope mounted on two rotating disks or dials (marked with degrees from 0 to 360). This telescope can be rotated horizontally and vertically to measure angles. Laser plummets are used to center the instrument over the station mark. A total station is a multipurpose surveying instrument that combines an electronic theodolite with EDM (electronic distance measurement). Total stations also measure angles, but also measure slope, distances, and elevations with high precision. Slope distance is integrated with the vertical angle to compute both horizontal and vertical distances. Highly sensitive electronic bubbles along with laser plummets allow the total station to be set precisely over a point.

Engineering and construction Surveys

Performed to layout, locate, and monitor public and private engineering works

1.1 How do plane surveys and geodetic surveys differ?

Plane Surveying neglects the spheroidal shape of the earth and considers the mean surface of the earth as a plane. The reference base taken as a flat horizontal surface on a single plane. All vertical measurements are taken relative to this horizontal plane. The level line is considered straight. All plumb lines and direction of gravity are considered parallel. All angles that are taken as plane angles. All triangles formed by survey lines are considered plane triangles. Doing so allows calculations to be done with plane geometry and trigonometry. Plane surveying is not used extensive areas because Earth's surface cannot be taken as a plane for such areas. In contrast, Geodetic surveys considers the ellipsoid shape of the earth. The surface lines are curved lines. The triangles are spherical triangles. Computations involves spherical trigonometry. Geodetic surveys involve a high degree of precision and work of a larger magnitude. (additional information from internet) Datum is used in surveying and geodesy where an approximation of the Earth's surface is used as a reference system against which positional measurements are made to compute locations. Horizontal datums are used to describe a point on the Earth's surface, in latitude and longitude or another coordinate system.

Intersection tie

Point P is located relative to known line AB by determining either the angles at A and B to P or by determining the distances AP and BP.

Angle-distance tie

Point P is located relative to known line AB by determining the angle (θ) at A and the distance AP

1.7 Describe how a very precise measurement can be inaccurate.

Precision is the ability to repeat the same measurement with consistently only small variations. a measurement of repeatability. If the equipment has certain errors (systematic) associated with a particular measurement, that measurement will not be accurate but easily may be repeatable. For example, temperature variations can shorten or lengthen a steel tape. Precise methods can also be inaccurate from random errors from the surveyor that lower precision.

Aerial surveys

Preliminary and final surveys using both traditional aerial photography and aerial imagery (includes the use of digital cameras, multispectral scanners, LiDAR, and radar)

1.2 Are preliminary (or data-gathering) surveys plane surveys or geodetic surveys? Explain your response.

Preliminary surveys can be both plane surveys and geodetic surveys. However, preliminary surveys are generally plane surveys. Some preliminary surveys done with geodetic surveys due to what equipment is used or when an extensive area is being surveyed.

1.3 (assigned question) What kinds of data are collected during preliminary surveys?

Preliminary surveys gather data that includes distances, positions, and angles of the positions of objects or points between objects (man-made or natural). Then this geospatial data is used to plot to scale the locations of physical features on a map or plan. Data is also collected about vertical differences so that elevations and contours can be plotted.

Random errors

Random Errors are associated with the skill and vigilance of the surveyor. Random (also known as accidental) errors are introduced into each measurement mainly because no human being can perform perfectly. The presence of random errors is the cause of low precision.

What is the importance of field notes in surveying?

Recording field data Field notes are a written and permanent record showing pertinent information, measurements, and observations made by the surveyor during the course of the survey. One of the most important aspects of surveying is the taking of neat, legible, and complete hand-written field notes. The notes will be used to plot scale drawings of the area surveyed and used to provide a permanent record of the survey proceedings. An experienced surveyor's notes will be complete without redundancies, well arranged to aid in comprehension, and neat and legible to ensure that the correct information is conveyed.

1.9 (assigned question) Describe several different ways of locating a physical feature in the field so that it later can be plotted in its correct position on a scaled plan.

Surveying measure points relative to a reference to plot these points on a scaled plan. Radial surveying measures the angle, direction, and distance from known control points to determine the location coordinates of physical features with location ties (right-angle, angle-distance, intersection). Stationing establishes a base line to locate physical features by measuring along and perpendicular to the base line. Lastly, aerial imagery using drones, and GPS receivers placed at the point can be used to establish the coordinates of the physical feature's location and then those points plotted on a scaled plan based on their positions.

1.6 (assigned question) Why is it that surveyors must measure or determine the horizontal distances, rather than just the slope distances, when showing the relative locations of two points? (assigned question)

Surveyors must measure horizontal distances rather than just slope distances when showing the relative positions of two points because the horizontal distance between two points does not change even if the ground is disturbed. If the surveyor used slope distances, then the distance between objects and places would change every time the grade changed. In addition, if all distance measurements are done on the same plane, a frame of reference can be established.

Cadastral Surveys

Surveys involved in defining and establishing boundary locations or in laying out new property boundaries lines (also known as cadastral or land surveys)

Geodetic surveying

Takes in account the curvature of the earth. Calculations are based on an approximation of the earth's surface, represented by a spheroid. Earth surface considered - spherical Line formed by joining any two points are considered as the same angles are spherical angles (Arch) Suitable for large area surveying Survey accuracy - high Method - Special instrument needed and long survey method

Beidou, or Compass

The Republic of China's regional satellite system which is now being rapidly expanded to a global positioning system

Accuracy ratio of a measurement or series of measurements

The ratio of error of closure to the distance measured. The accuracy ratio is expressed as a fraction whose numerator is one and whose denominator is rounded to the nearest 100 units NOTE: since a ratio, no units NOTE: It should be emphasized that for each of these specified orders of accuracy, the techniques and instrumentation used must also be specified.

Geomatics

The science and technology dealing with geospatial data (including data collection, analysis, sorting, management, planning and design, storage, and presentation)

Who can perform surveys?

To be licensed to do land surveying (boundary or property surveying) where legal boundaries are established or re-established North American surveyors must first pass state/ provincial exams and obtain years of field training. Engineering surveys are performed by surveyors with a civil engineering (or civil engineering technology) education. The person must also have suitable field experience, and prepared to perform a wide variety of pre-engineering and construction layout surveys. Some programs (including Geomatics) produce "professional" surveyors capable of working in both fields. Some "layout surveys" on large projects, once performed by both engineering and land surveyors, are now being done by construction equipment operators who are guided by in-cab interactive monitors or other line and grade signaling devices.

What is stationing?

When performing route surveys, measurements can be taken along a baseline and at right angles to that baseline. Stations (chainages): Distances along a survey baseline Simple dimensions (offset distances): Distances at right angles to that baseline The beginning of the survey baseline (is the zero end) is denoted by 0 + 000 or 0 + 100. 1,000 unit stations work well with the metric system. In those countries using metric units, most municipalities have kept the 100-unit station (i.e., 1 + 00 = 100 m), whereas many highway agencies have adopted the 1,000-unit station (i.e., 1 + 000 = 1,000 m). **Extra information from the internet A station is both a dimension (fixed length with an associated unit) and a position ( the cumulative horizontal distance along the alignment from its beginning). In the metric system, a station may be 100 m or 1000 m with a corresponding partial station. A point 12,56.02 m along the alignment would be at station 12+26.02 or 1+256.02.