Basics of the Surveying
- Surveying is defined as the science of making measurements especially of the earth surface. This is being done by finding out the spatial location (relative/absolute) of points on or near the earth surface.
- Different method and instrument are being used to facilitate the work of surveying.
Objective of Surveying
- To collect field data.
- To prepare plan or map of the area surveyed.
- To analyze and calculate the field parameters for setting out operation of actual engineering works.
- To set out the field parameters at the site for further engineering works.
Modern Surveying Equipment
- Revolutionary changes have taken place in last few years in surveying instruments that are used for measuring level differences, distances and angles.
- This has become possible because of introduction of electronics in these measurements. With rapid advancements in the technology and availability of cheaper and innovative electronic components, these instruments have become affordable and easy to use.
- Recently electronic digital levels have evolved as a result of development in electronics and digital image processing.
- Digital levels use electronics image processing to evaluate the special bar-coded staff reading.
- This bar-coded pattern is converted into elevation and distance values using a digital image matching procedure within the instruments.
Salient Features of Digital Level
- Fatigue-free observation as visual staff reading by the observer is not required.
- User friendly menus with easy to read, digital display of results.
- Measurement of consistent precision and reliability due to automation.
- Automatic data storage eliminates booking and its associate errors.
Components of Digital Level
- The following discussion on digital levels has been primarily taken from Schoffield(2002).
- Main components of digital level consist of two parts: Hardware (Digital level and leveling staff) and Software.
- Both digital level and associate staff are manufactured so that they can be used for both conventional and digital operation.
- Typically digital level has the same optical and mechanical components as a normal automatic level.
- However, for the purpose of electronic staff reading a beam splitter is incorporated which transfers the bar code image to a detector diode array.
- The light, reflected from the white elements only of the bar code, is divided into infrared and visible light components by the beam splitter.
Capabilities of Digital Levels
- Measuring elevation.
- Measuring height difference.
- Measuring height difference with multiple instruments positions.
- Setting out with horizontal distance.
- Levelling of ceilings.