A Better Way To Understand Theodolites

Since ancient civilizations in Mesopotamia, Egypt and Rome, man has used tools to measure and keep his boundaries and separate himself from his neighbors. While the use of such tools were all but lost in the Middle Ages, the Renaissance saw a resurgence in interest and need in tools to survey and parcel the land around them. Many tools still used today are much like those used to map and survey the initial settlements of america. We are at the dawn of a brand new era, alternatively, where technology that has not drastically changed within the past hundreds of years will be introduced to the computer age, which has served to only make man's estimations even more accurate than before.

In its earliest forms, one of the main tools for conducting land surveys was a chain (sometimes called a Gunter's chain) of a particular length. These chains will be pulled taut, and attempts were made to hold the measure level in order to improve accuracy.

Leaps and bounds in accuracy in surveying were made with the introduction of such equipment as the surveyor's compass and theodolite. The surveyor's compass, or circumferentor, consisted of a brass circle and an index; on the circle was a compass. It was used to measure horizontal angles. A theodolite could measure both horizontal and vertical angles. Due to the greater accuracy, the theodolite was the preferred tool for surveyors throughout Europe through the early 1800s. On the flip side, due to its bulk, the surveyor's compass was still employed in heavily wooded areas, leading to its resurgence in popularity during the Colonial period within the usa.

Theodolites, though more sophisticated versions, were still used as late as the 1990's for simple surveys, as well as other equipment to improve the accuracy. More recently, modern electronics have improved on the theodolite with the addition of an electronic distance measurement device, or EDM; these tools are referred to as total stations. In a short period of time, total stations have gone from being mechanical/electronic devices to purely electronic systems with onboard computer and software.

Linear surveying is one of the most basic methods of surveying and involves no measurement of angles. Whilst often now overlooked in favour of hi-tech theodolites and GPS equipment, It may be used to plot single features or whole towns. However it really is most suited for small scale projects as accuracy can suffer over larger areas but it does give a cheap alternative to sophisticated but expensive measurement equipment.

How Does Linear Surveying Work? This method involves establishing a linear baseline throughout the area which is to be measured/plotted. Over short distances this can be achieved with a tape between two rods but over longer distances the baseline is best constructed by a team of at least two surveyors. One surveyor can stand at the previous rod and ensure the next rod is put in the ground in-line with the others.

Once a perfectly straight baseline is established then another tape can be obtained from the baseline to an point that needs to be measured/plotted. The key is the fact that this line is taken at exactly a 90 degree angle from the baseline. This can be ensured through the use of a standard surveyors triangle.

The 2 linear measurements that need to be taken are the distance of the point along the baseline and secondly the distance from the baseline. By having these measurements from all of the points required, it really is then possible to plot them and produce a drawing of the site.

For larger or maybe more complicated sites it is strongly recommended to set up multiple baselines throughout the site with ideally each point being measured from more than one baseline to improve accuracy.

Global Positioning Systems have also entered the arena of land survey, as well as have steadily gained in knowledge and use in the non-public field. For land surveying, alternatively, they may be not absolutely as accurate as the surveyor would wish. Although they have increased the speed of surveying, GPS systems will be just horizontally accurate to 20mm and vertically accurate to about 30mm. What's more, GPS systems have problems functioning properly in heavily wooded areas. In lots of cases, surveyors will still depend upon their total stations in conjunction with other equipment such as laser scanners. Where the budget is big enough, a helicopter equipped with a GPS system can verify the findings on the ground.

While the technology utilized by land surveyors has been changing and moving forward by leaps and bound within the last 25 years, even the most advanced technology may only do so much. Land surveying remains an art, with the help of the surveyor can't be replaced by technology. The surveyor must investigate and infer just what the true boundaries associated with any property might be using both the technological and historical information they have at hand.