Linear shooting is one of the most basic shooting methods and does not require angle measurement. Although it is often overlooked in favor of high-tech theodolites and GPS equipment, it can be used to build individual objects or entire cities. However, it is most suitable for small projects, since accuracy may suffer in large areas, but it offers a cheap alternative to sophisticated, but expensive, measuring equipment.
How does linear surveying work?
This method involves establishing a linear baseline across the area to be measured / constructed. At short distances this can be achieved with a tape between two rods, but at longer distances the base line is best constructed by a team of at least two surveyors. One surveyor can stand on the previous rod and ensure that the next rod is placed in the ground in a row with others.
Once a completely straight baseline is established, you can take another tape from the baseline to the point you want to measure / build. The key is that this line is taken exactly 90 degrees from the baseline. This can be achieved using a standard surveyor triangle.
The two linear measurements that need to be taken are the distance from the point along the baseline and, secondly, the distance from the baseline. Having these measurements from all the required points, you can then build them and create a drawing of the site.
For larger or more complex sites, it is recommended to install several baselines throughout the site, and ideally each point is measured from several baselines to improve accuracy.
What equipment is needed?
Linear shooting requires only very basic equipment:
- Tape Measures
- Triangle tracking
- Measuring rods
- Notebook to record results
- Bundles (to secure the crane to the rods to help in providing a straight line)
Disadvantages?
- Accuracy can suffer over large areas (it is difficult to provide a direct baseline)
- The environment can affect the ability to establish a baseline (water obstacles, uneven terrain, etc.),
- You must install several baselines so that you can verify and assist with accuracy.
Thus, in conclusion, linear imaging is a traditional survey method that can provide accurate results with careful observation and using several baselines to confirm measurements. However, in fact, it is used only as an academic exercise or on small sites where accuracy is not critical.
Otherwise, it is more appropriate to use more modern approaches, including theodolites and GPS equipment.
