Intro to Surveying

Laser Scanner

Can collect tens of thousands of positions to in fraction of time compared to traditional surveying methods with no reduction in accuracy.

GPS Receivers

Can determine 3 dimensional positions to under 1 centimeter

Total Station

Can measure angles to 1 second and distances to 3 mm + 3ppm

Chain

Capable of measuring precise distances.

Transit

Capable of turning both horizontal and vertical angles and directions precisely.

Compass

Capable or determining directions and rudimentary angles.

2500 B.C.

Archaeologists have found Babylonian maps on tablets of that estimated age Evidence has also been found in the historical records of India and China that show that surveying was practiced in those countries in the same time period.

1800 A.D.

The importance of "exact boundaries" and the demand for public improvements (i.e. railroads, canals, roads) brought surveying into a prominent position.

Metric Chains

- 20m and 30m - Tallies every five meter length - brass rings every meter length

Gaunter's Chain or Surveyors Chain

- Length: 66ft (22 yards), No. of links = 100, Each link = 0.66' - Used for measuring distances in miles or furlongs (220 yards), acre (area)

Check lines

- Or proof line is a line joining the apex of a triangle to some fixed points on any two sides of a triangle. To check accuracy of the framework. - The length measured on the ground should agree with its length on the plan.

Instrumental Method

Some instruments like Speedometer of an automobile, Pedometer etc. may also be employed to find the distance approximately. Speedometer gives better results than pacing provided the route is smooth as along a highway

direct measurement

Under linear surveying, where distances are measured using Chain or Tape measurements or Ranging

Electronic Methods

Under linear surveying, where measurements are through propagation, reflection and subsequent reception of either radio or light waves

Measurement by Optical Means

Under linear surveying, where observations are obtained through telescope and distances are determined through computation

As-built surveys

are made after a construction project is complete to provide the positions and dimensions of the features of the project as they were actually constructed. Such surveys not only provide a record of what was constructed but also provide a check to see if the work proceeded according to the design plan.

Mine survey

are made to obtain the relative positions and elevations of underground shafts, geological formations, and so on, and to determine quantities and establish lines and grades for work to be conducted.

Forestry and geological surveys

are probably much more common than the average layperson realizes. Foresters use surveying for boundary locations, timber cruising, topography, and so on. Similarly, surveying has applications in the preparation of geological maps.

Five Main Areas of Surveyor's Work

1. Research, analysis, and decision making. 2. Field work (Data acquisition). 2. Field work (Data acquisition). 4. Mapping (Data representation). 5. Stake-out.

Geomatics

In 1988 the Canadian Association of Aerial Surveyors introduced the term __________ to encompass the disciplines of surveying, mapping, remote sensing, and geographic information systems.

Construction Survey

Survey made to control the horizontal and vertical positions, dimensions, and configuration of a design.

Fully Graduated, First Foot, Extended Foot

Three standard type of modern surveying chains:

Cloth or Linen, Metric Steel, Invar, Synthetic

Types of Measuring Tapes:

Remote sensing

is another type of aerial survey. It makes use of cameras or sensors that are transported either in aircraft or in artificial satellites.

Plane Surveying

Assumes that the survey area is a flat plane. Generally covers small areas (less than 300 sq. mi.).Most common method used.

Engineer's chain

- Length- 100 ft., No. of links=100, Each link = 1' - Used in all Engineering Surveys

Revenue Chain

- Length= 33 ft, No of links = 16 - Commonly used for measuring fields in cadastral survey

Route Survey

A survey for the reconnaissance or to select the most feasible route for a highway, railroad, transmission line, or types of corridor facilities.

Cadastral Survey

A survey relating to land boundaries and subdivisions made to create units suitable for transfer or to define limitations of title. - Original surveys - Retracement surveys - Subdivision surveys

Topographic Survey

A survey which has for its major purpose the determination of the configuration of the surface of the earth and the location of natural and artificial objects thereon.

Control Survey

A survey which provides data, such as horizontal position and vertical elevation data for the support of subordinate surveys or for mapping.

perpendicular offset

an offset wherein the measurements are taken at right angle to the survey line

Photogrammetric surveys

are those in which photographs (generally aerial) are used in conjunction with limited ground surveys (the latter being used to establish or locate certain control points visible from the air).

Base Lines

It is main and longest line, which passes approximately through the center of the field. Detailing work carryout with respect of this line.

Marine surveys

It is related to hydrographic surveys, but they are thought to cover a broader area. They include the surveying necessary for offshore platforms, the theory of tides, and the preparation of hydrographic maps and charts.

offsets

It is the lateral measurements from the base line.

Surveying

It is the science of determining the dimensions and contour (or threedimensional characteristics) of the earth's surface by measurement of distances, directions, and elevations.

Chain Survey

It is the simplest method of surveying. Only measurements are taken in the field and the rest of work are done in the office.

Judging Distance and Time Measurements

For very approximate results such as in reconnaissance survey, the distances may be determined by judgement only. The distances are also roughly determined by knowing the average time taken per km by a person at walk or a horse at trot and the total time taken to cover that distance.

120 B.C.

Greeks developed the science of geometry and were using it for precise land division. Greeks developed the first piece of surveying equipment (Diopter). Greeks standardized procedures for conducting surveys.

Hydrographic survey

It pertain to lakes, streams, and other bodies of water. Shorelines are charted, shapes of areas beneath water surfaces are determined, water flow of streams is estimated, and other information needed relative to navigation, flood control, and development of water resources is obtained.

Swinging, Using cross staffs, Using optical or prism square

Methods for setting perpendicular offsets:

oblique offset

Offset at some angle

Geodetic Surveying

Takes into account the theoretical shape of the earth. Generally high in accuracy, and cover large areas.(greater than 300 sq. mi.).

1400 B.C.

The Egyptians first used it to accurately divide land into plots for the purpose of taxation.

Pacing

The method consists in walking over a line and counting the number of paces.

Chaining

The operation of measuring distance with the help of a chain or a tape. It is the most accurate of all the methods of measuring distance and is commonly used.