Surveying Fundamentals

What are some of the various surveying instrumentation?

- Chain and compass - Steel tapes - Level to Autolevel - Transit - EDM & Theodolite - Total station & data collector - Digital level - Robotic total stations & data collector - GPS/GNSS - Photogrammetry / Remote Sensing (Static[laser scanner]) (Kinematic [GNSS/IMU])

What are mistakes? What should we know about them?

- Mistakes are blunders made by survey personnel - Mistakes must be discovered and eliminated, preferably by the people who make them - All survey measurements are suspect until they have been verified ** Verification can be as simple as taking the measurement again or with geometric/triogonometric analysis

What is the Accuracy Ratio?

- Ratio of error of closure to the distance measured - The error of closure is the difference between the measured location and the theoretically correct location - The theoretically correct (estimated/predicted) location can be determined from repeated measurements or mathematical analysis - Since relevant systematic errors and mistakes can and should be eliminated from all survey measurements, the error of closure will be composed of random errors

What are two applications of surveying?

- The location of ground? features are measured to prepare a map or plan of the area - Design features, shown on a map or plan, are located in the field by distance, angle and/or positioning measurements

In science and engineering in general an error is defined as:

- difference between the desired and actual - difference between the measured and true

What are the three classes of surveys?

1. Boundaries 2. Planning & Construction 3. High Precision / Government / Geodetic

What surveyors do.

1. Determine, measure and represent the land, 3D objects, point-fields, and trajectories 2. Assemble and interpret land and geographically related info 3. Use that info for the planning and efficient admin of the land, sea, and structures; and 4. To conduct research into the above practices and develop them

What are the two types of errors?

1. Systematic - errors whose magnitude and algebraic sign can be determined (Fixable) 2. Random - errors are associated with the skill and vigilance of the surveyor (Maybe NOT Fixable) No measurement is free of "error"

Surveying is the art and science of:

1. measuring angles 2. measuring distances 3. measuring positions Also considered the THREE major functions

Survey crews (parties) often comprise a:

1. party chief 2. an instrument operator 3. survey assistant - Two person crews are more common when modern electronic equipment is being used

Precision and Accuracy (ERROR vs. Residual) (Just Read)

Accuracy (of an Error) is the relationship of a measurement and the "true" value (unknown) of the dimension being measured) Accuracy (of an Residual) is the relationship between the value of a measurement and the "estimated" value (predicted) of the dimension being measured Precision describes the refinement of the measuring process and the ABILITY TO REPEAT THE SAME MEASUREMENT WITH CONSISTENTLY SMALL VARIATIONS in the measurements

Accuracy Ratio Illustrated:

Distance Measured: 250.56 ft Previously Known: 250.50 ft Error is 0.06 ft in a distance of 250.50 ft Accuracy Ratio: 0.06/250.50 = 1/4,175 = 1/4,200 (Approx.) The accuracy ratio is expressed as a fraction whose numerator is unity and whose denominator is rounded to the closest 100 units

What is the difference between ERROR and Residual?

Error is the relationship between the value of a measurement and the "true" value (unknown) of the dimension being measured Residual is the relationship between the value of a measurement and the "estimated" value (predicted) of the dimension being measured FOR THIS CLASS WE WILL TREAT THEM THE SAME

Horizontal and slope distances can be measured with a fiberglass or steel tape or with an electronic measuring device

Ok

Stationing (Mostly Route Surveys) - Stations are dimensions measured along a baseline - The beginning point is described as 0+00 - A point 100 ft (m) from the beginning is 1+00 - A point 565.98 ft (m) from the beginning is 5+65.98 - Points measured before the beginning station are 0-50, -1+00, etc. - Metric = 1+000 (Just Read)

Ok

When surveying, the horizontal distance is ALWAYS required; if a slope distance between two points has been taken and recorded, it must then be converted to its horizontal equivalent

Ok

What are the types of surveys?

Plane Surveying - the surface of the earth is considered to be a PLANE for all X and Y dimensions Geodetic Surveying - the earth is considered to be ELLIPSOIDAL for X & Y dimensions

Another definition of surveying

The science, art, and technology of determining the RELATIVE positions of points above, on, or beneath Earth's surface, or of establishing such points

Who can perform surveys?

Two LARGE fields (By Law) 1. Survey (Engineering?) 2. Land (Boundary) Survey?