The second month's learning and practical journey: Initial experience of Topographic (Topo) Surveying
In my second month of working in the Definition Surveying team, I had my first encounter with Topo surveying. David, as usual, entrusted the task to me and asked me to plan and complete it myself. This put a lot of pressure on me, but I am well aware of the importance of hands-on experience. It looks easy when you watch, but it is easy to mess up when you try for the first time. David emphasizes the value of hands-on practice by letting me do it myself, I believe this is a rare learning opportunity. I know that David is facing various pressures, and he has created this opportunity for me. I appreciate and cherish the opportunity to learn this way.
After David provided an overview and brief about what was required, I began to sort out the ideas for completing the task.
Preparation work
1. Understanding customer needs:
Firstly, I carefully read the information provided by the client to fully understand their needs. In this particular case the task is to complete a topo survey so that a design could be carried out to allow for the entry of large vehicles to a site. Due to the small size of the original intersection, a corner of the intersection had to be widened, so a Topo survey of the area was required.
2. Learning relevant knowledge:
In order to ensure the smooth completion of the work, I reviewed a large amount of materials and videos to gain a deep understanding of the process and precautions of Topo surveying, and ensured that no details are missed or data deviations occur.
3. Collecting information:
Through Google Maps and Land Information New Zealand (LINZ), I collected information on the measurement area, grasped its features, determined the Control mark and Check mark, and planned the measurement steps and sequence.
4. Safety preparation:
The biggest risk during the measurement process is highway surveying. This is a live State highway, although not a main road, there are still vehicles passing by. Before departure, David instructed me to always pay attention to passing vehicles and ensure my own safety when measuring on the road. In addition to wearing high visibility clothing, it is also necessary to observe the movement of vehicles through sound and light, and never rely on the driver's attention for safety. When discovering vehicles, it is important to stay away from the road in a timely manner and not take risks due to the rush to collect data. We used our approved generic Traffic Management Plan and followed the requirements to complete the task. We had a truck with a flashing light and used a spotter to complete the survey pick up next to the road.
Measurement work
After preparing, I brought the equipment to the site. Although the process was generally smooth, two issues were encountered:
1. Selection of measurement location:
The measurement area includes roads, drainage ditches, fences, and grasslands, with frequent changes in height and angle. I hesitated when determining the measurement location, which led to confusion when using Codes to create the line work for site features.
2. Difficult to find road junctions:
Sealed and unsealed roads had been in use for a long time, and the junction points is difficult to distinguish.
In order to comprehensively reflect the characteristics of the measurement area, I tried to measure as many as possible and ultimately collected data from 537 measurement points.
The Trimble TSC7 Data Collector (TSC7) can display the basic appearance of the measurement area. But after we imported the data into Trimble Business Center (TBC), it was filled with small red flags, indicating that there was an issue with some of the points I recorded. David checked TSC7 and the data, sorted out my work process, and did not find any problems with what had been done but the order of the pick up meant that I spent a long time modifying the codes at night, but I still have doubts about what I had done. So the next day I proposed the idea of measuring some points again to David. He smiled meaningfully (as if everything was under his control). He has already prepared the drone and was ready to go back to the site to capture an up to date aerial photo and teach me how to do the codes better.
In the second measurement process, David first demonstrated his surveying method, and I carefully observed and raised questions. He answered my questions with professional knowledge based on his experience.
Director and LCS David leading the way.
Lessons Learned
1. Correct use of codes:
When surveying on site you need to take note of where the features, heights and angles change. Measurements must be carried out and a beginning code must be used to start line strings so that the points can accurately reflect the appearance of the measurement area. These can ensure that the graphics displayed on TSC7 are neat and tidy and reduce the workload of later data processing.
2. Distinguish road intersections:
For situations where the junction points between sealed and unsealed roads cannot be distinguished by features, it can be determined by angle changes, as the settlement speed varies depending on the materials used for the road.
3. Solve the Little Red Flag problem:
David noticed that I made an error while selecting the Rover measurement mode, resulting in the data being marked with a small red flag.
Following his guidance, I quickly completed the work with minimal modifications required for post-processing the data. Subsequently, David demonstrated how to combine photos taken by drones with measurement data to create a topographic plan. He explained that using drone photos instead of Google Maps is because Google Maps may sometimes have deviations, and the shooting time may differ significantly from the actual measurement time, so changes may have occurred in the area.
Through this experience, I have gained a comprehensive understanding of topographical surveying and mapping terrain with a GPS. I have also learned many skills and noted areas that require special attention in practical operations. Thanks again to David’s careful guidance and tolerance, I have been able to grow rapidly and take another step developing my skills as a Surveyor.