LECTURE 3 Flashcards
Give at least 1 method and instrument for
determining horizontal distance
- Pacing
- Tacheometry
- Graphical and
Mathematical Methods - Mechanical Devices
- Photogrammetry
- Taping
- EDM
- Global Positioning
Systems
What are the factors to be considered in choosing methods
- Purpose of the measurement
- Required Accuracy
- Cost
Consists of counting the number of steps in a required distance
Pacing
Length of a step in walking
Pace
Factors Affecting Length of Pace
- Speed of pacing
- Roughness of the ground
- Weight of clothing and shoes
- Fatigue on the part of the pacer
- Slope of the terrain
- Age and sex of the individual
Pace counter worn on the belt that simply records the number of steps made based on the body’s movement (hips)
Pedometer
Registers a pace by impact each time a
foot touches the ground
Passometer
Methods in Tacheometry
- Stadia Method
- Subtense Bar Method
Method in Tacheometry which uses a telescope with 2 horizontal cross hairs
Stadia method
Method in Tacheometry in which a bar is set up at a distant station while a theodolite at the end of the line measures the horizontal angle subtended by the distance between the two targets
Subtense bar method
Attached to a wheel for purposes of
roughly measuring surface distances
Odometer
Mechanical device used for determining distance along irregular or curved lines and
boundaries.
Measuring wheel
Similar to odometer except that
it is a more portable and self contained device.
Measuring wheel
Indirect method of measuring horizontal
distances. It is based on the optical geometry of the instruments used.
tacheometry
mechanical device that determines distances approximately by focusing
Optical rangefinder
