Surveying Instrumentation

• This lesson covers basic instrumentation used in surveying.
• The objectives are to know the basic instrumentation used, and to identify the use of each instrument.

Instrumentation

• Surveyors use a variety of tools, instruments, and techniques to obtain data and represent it in a plan.
• High-precision instruments facilitate the surveyor's work.
• It is important to know the use and limitations of each instrument for proper selection.
• Instruments have evolved with technology, becoming more precise and multifunctional.

Instrument Categories

• Instruments can usually be divided into three main categories:
  • Measuring angles
  • Measuring distances
  • Measuring slope

Instruments for Measuring Angles

• Compasses: used for orientation
• Transits
• Theodolites

Instruments for Measuring Distances

• Measuring tape
• Odometers
• Distance meters
• Total station

Instruments for Measuring Slope

• Levels
  • Hand levels
  • Line level
  • Electronic levels

Field Book

• Contains all field annotations, data, diagrams, and descriptions.

Compass

• A handheld instrument is used for orientation.
• Determines Earth’s magnetic north (always indicates magnetic north using Earth's magnetic field).
• It has a magnetized needle mounted on a pivot with a calibrated circle (compass rose) that rotates freely on the axis and points north.
• Measurements with compasses can be affected by elements such as high tension cables potentially affecting or locally altering the magnetic field.

Plumb Bob

• Instrument in the shape of a cone, cylinder or prism.
• Constructed generally of bronze.
• Attached to a rope, hanging freely and follows the direction of the vertical line.
• Uses the gravity of the earth to mark the vertical line.
• Used to measure the verticality of walls, and alignment.

Stakes

• Stakes are made of wood or iron
• It’s a sharp object that is nailed into the ground used to mark or establish limits.

Needles

• Steel rod, 30 cm long with a diameter of 1/4".
• Painted in alternating red and white stripes.
• Sharp metal object that is nailed into the ground.
• Used to mark or set boundaries
• Usually come in sets of 11 needles

Nails

• Used to mark points on asphalt or concrete.

Measuring Tape

• Useful for measuring short distances on the ground
• To mesure the height of an instrument
• In terms of the 'wincha' measuring tape.
  • It is used for distances greater (50 to 100 m).
  • It's flexible.
  • It’s used for measuring horizontal distances.

Odometer

• Consists of a wheel with a perfectly defined diameter (1.20 m in circumference).
• Has a device to count turns.
• Is used to measure distances.

Sledge Hammer

• Used to place stakes and nails.

Paints

• Used for marking or identifying points on surfaces.

Jalon

• Long rod with a cylindrical or prismatic section.
• Can be made of wood or metal with a steel tip for nailing into the ground.
• Originally, it was a long rod of wood.
• Used for locating fixed points and drawing alignments.
• The prism is placed on top.
• It has a bubble level so it can be kept level when taking measurements.

Prisms

• Accessories for making measurements (mirrors).
• Typically placed on the rod.
• Reflects the beam emitted by different instruments, allowing measurements to be taken.

Tripods

• An auxiliary instrument that serves as a base for the different topographic equipment.
• It has three legs and a base that is circular or triangular that allows for positioning the instruments.
• The plate has a screw used to secure the equipment.
• Can be made of wood, aluminum, or a combination of materials with adjustable legs to accommodate the operator.
• The tips of the legs are metal and end in an iron point to be able to step on it and nail it in the ground.

Levels

• Levels are designed to measure the height difference between two points or the height difference between points, also known as vertical distance.

Hose Level

• The simplest method to determine slopes between two points.
• Water is introduced into a transparent hose, and both ends are raised.
• The water will be at the same level at both ends due to simple balance.

Hand Level

• A simple instrument where horizontality is measured through a drop in a glass bubble.
• Is a tubular structure about five inches in length.

Line Level

• Simple instrument made up of a bubble of glass over a frame.
• Frame is placed on a thread (line) to measure horizontality.

Mechanical Level

• Were the first instruments used in topographic measurements.

Automatic Level

• More practical to manipulate.
• Have an optical compensator.

Electronic Level

• State-of-the-art.
• Requires special bar code targets to perform readings.
• Measurements are fast and save appreciation or reading errors because they have memory to store and process data.

Laser Level

• A novelty
• Projects a laser beam that allows alignment.
• Mostly used in interior jobs because they project a line on the wall and outdoors the projection of the line is difficult to see.
• Can be used by one person

Surveying Rod

• Calibrated rod with rectangular section that allows to measure the difference in elevation (height) or vertical distances.
• Can be made of wood, fiberglass or aluminum.
• Usually 4 or 5 meters divided into 1-meter foldable sections for easy transport and storage.

Mechanical or Electronic Theodolite

• Optical instrument similar to a telescope for measuring angles.
• Used to obtain vertical and horizontal angles.
• Can measure distances using other auxiliary tools.
• Configuration consists of a telescope mounted on a single support with two graduated circles, one vertical and one horizontal.
• The first theodolite was built in 1571 by the Englishman Leonardo Digges.

EDM (Electronic Distance Measuring)

• It is a distancemeter - electronic device for measuring distances.
• Emitting a light beam, either infrared or laser.
• Beam bounces off a prism or directly on the surface.
• The distance is determined, depending on how long it takes the beam to travel.
• Only measures the inclined distance.
• To measure horizontal distance and unevenness, some have a keyboard to enter the vertical angle.
• Some distance meters have a port for receiving information directly from an electronic theodolite to obtain the vertical angle.

Handheld Distance Meter

• Portable
• Easy to handle

Total Station

• An electro-optical instrument that incorporates an electronic distance meter and theodolite to measure horizontal angles, vertical angles, and distances.
• Used for staking out
• All measurements and additional information can be recorded.
• Handle with care, move properly by loosening the screws.

GPS (Global Positioning System)

• A global navigation system that allows determining at all times the position of a point on the surface of the earth (latitude and longitude) with high precision.
• Makes use of a network or constellation of satellites orbiting the earth and transmit signals to a GPS receiver.
• GPS can have one band (L1) and dual band (L1, L2).
• The difference in price of a GPS of a band against a two-band GPS can be very large, and it is all the more so when the two-band GPS include the RTK (Real Time Kinematic) function
• GPS does not replace the total station in most cases they complement each other
• GPS is practical in large-scale surveys since it has space with a view to the sky and improves reception and it increases productivity, since data collection is faster.
• There are portable models (handheld), whose precision is lower and there are models that are installed on tripods for data collection over longer periods in which a data rectification process occurs.

3D Scanner

• This instrument allows to collect and capture data from the environment in 3D.
• Capture precise and three-dimensional information from an object or a group of objects of the real world, or from an environment, using laser as source of light.
• Projecting laser light on scanner produces clouds of points that define the position of the object in space with measured precision, and is capable of collecting vast amount of data in a short time period.
• Requires high capacity equipment (computers).
• It’s costly.

Drones

• Collects data quickly.
• Has the ability to collect large amounts of data in a single flight is possible to conduct surveys and topographic surveys with the same quality with the traditional methods.
• Maps areas that otherwise would be inaccessible.
• Complemented with aerial photos.
• Requires a flight plan.
• Cost varies according to use is proposed, precision and compatibility of accessory that can be added.

Advancements in Technology

Are resulting in new approaches and methods for surveying.

Recommended Footwear

• Recommended waterproof boots
• Leather: Provides better support and protection to the foot and ankle
• Rubber: Typically cover more and are easy to clean.

Recommended Clothing

• Use of long pants is highly recommended.
• Short pants or skirts should be avoided
• Long sleeved shirts are preferred.

Head Protection Safety

• A hat helps protect not only the face, but also the neck and ears from the sun's rays.
• A baseball cap doesn't provide the same protection, it only protects part of the face.

Eye Protection Safety

• Eye protection is important through using safety glasses, preferably.

Skin Protection Safety

• Is recommended to include a sunscreen.

Hydration Safety

• Drink water regularly (15-20 minutes).
• Fresh water, not cold.
• Do not wait until you are thirsty to drink water.
• If a worker experiences heat stress, transport them to a cool area with shade.
• Lay on your back with your head slightly elevated.
• Give fluids, if possible containing salt and sugar.
• Apply cold compresses or even ice.

First Aid Kit

• Wet wipes
• Analgesics
• Antihystaminic (ointment and pills)
• Bottled water
• Toilet paper
• Energy bars
• Bandages
• Alcohol
• Peroxide