Parallels between classical and modern topographic surveying methods

History of topographical measurements

Drawn up as a means of illustrating Michael the Brave’s battles against the Turks, the first informative maps of the Roman Lands appeared in 1596 in Italy and Germany. The first maps illustrated by romanians were those made by the stolnic Cantacuzino in 1700 for Valahia Mare and that of Moldavia by Dimitrie Cantemir in 1737. The map of Moldavia had the geographical meridians and parallels drawn on it.

Throughout history, the progress made in science in the world has had echoes in our country, concerns in this field gradually materializing with the first map of Moldavia drawn up by Dimitrie Cantemir and printed in The Hague in 1737, the first large-scale topographic surveys in Moldova and Muntenia, between 1872-1892, to meet the needs of the army.

After 1989, Romania aligns itself with modern technologies and introduces the Global Positioning System (GPS), total stations, satellite remote sensing records and state-of-the-art scanning and computing equipment.

Efforts in this direction accelerate the automation of systems, help increase measurement accuracy and data processing speed, and contribute significantly to the modernisation of the topographic measurements performed.

Classical measurement methods

The development of the science of land surveying, and of topography in particular, must also be seen in close connection with the emergence and continuous improvement of geotopographic instruments.

In surveying work, tape measures are used for direct measurement of distances, usually made of special steels.

The rollers have lengths of 2m, 10m, 20m, 30m and are used to measure short distances, the height of the device in the station and topographic signals.

The ribbons are made of 15 – 20 mm wide steel strip and are 50m or 100m long, guaranteed at 200C.

Optical distance measurement is carried out using a specific instrument with a telescope and a graduated ruler. Tachometers are instruments where the measured base is at the target point and rangefinders have the base built into the instrument.

Modern measurement methods

Modern surveying instruments (total stations, GPS system) are based on the indirect measurement of distances using waves in the electromagnetic radiation spectrum as the carrier of the measurement signal.

Total stations

Electronic distance measurement is carried out at the total station with the EDM (Electronic Distance Measurement) device, using waves from the electromagnetic spectrum. It allows convenient, fast and highly accurate measurement of both angles and distances, their automatic display and recording and transfer to a computer, as well as having built-in specialised software for solving lifting and plotting problems.

GPS system

The Global Positioning System (GPS) is based on the measurement of distances by waves, and is accepted and used today almost exclusively, the results generated positioning it as clearly superior to classical triangulation in terms of accuracy, yield and economic efficiency.

Distance measurement using laser radiation

Alignment and positioning lasers can also be used for certain categories of construction work. The procedure involves making alignments by quickly positioning a point within a local axis system and accurately measuring distances.

Alignment lasers are used to achieve a rigorous straight line. The instruments used emit an automatically horizontalising/verticalising laser beam from a helium-neon gas tube.

Positioning lasers are portable or rotating and allow the planimetric position of a point to be determined within a local coordinate system at distances of up to 50-60m. They collect data from three bar-coded sights via a rotating beam and calculate the x, y plane coordinates within seconds.

3D laser scanning is a modern measurement method used to generate the complete digital 3D model for buildings or objects, with precise measurements including high scanning beams (up to 340m) and easily generating the 3D BIM (Building Information Model) so useful for architects, designers and builders.

Among the benefits of the modern 3D laser scanning measurement method we can find:

 

  • Rapid measurement
  • Maximising safety for all party involved (data is collected from a safe distance on the ground).
  • Significant time and cost savings
  • True picture of the project
  • As-Built plans completed in a very short time
  • High data capture speed
  • Recording millions of measured points in seconds
  • Safe measurement in hard to reach or dangerous areas (can be done up to 340 m from the measured target)
  • Detailed information contained in a single point cloud.

How can Eurosurvey help you?

Eurosurvey provides its clients with state-of-the-art professional equipment and full technical support provided through its team, accumulated experience and expertise in the field of topographic measurements.

The services provided ensure the highest level of competence in engineering practice, the results achieved are testament to the professionalism, vision and experience that recommend us.

We invite you to consult our page for all the information you need and to contact us for any queries you may have about the subjects and projects we can be involved in.

Despre autor

Land surveyor / Team leader 3D laser scanning department

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