There are several kinds of surveys which you may perform for construction projects and real estate developments. Mainly, a survey involves marking an underground utility location, locating a property boundary, and finding an existing building dimension.
All types of surveys need a different kind of professional. If a survey project uses control points, then those surveys will be connected to a unified environment, which references the real-world location.
Around four survey control points are normally required to properly align projects to the real-world coordinates collected on a job site.
But knowing how to carry out control point surveys will ascertain that there is a high level of precision. You can learn how to do a control point survey through the following:
1. Know the Main Requirements
There are several requirements for GCPs (ground control points). The major requirement for GCP is the visibility you may find in your photographs.
Basically, ground control points need to be about half a meter and painted in contrasting colors to vary from the surroundings. The center point needs to also be identified easily. You may create a GCP yourself or even consider buying them.
2. Lay Control Points
The laying process of both kinds of control points, including CHPs and GCPs, remains the same. But if you are looking to effectively lay control points, you might want to do the following:
- Evaluate your mission’s altitude
- Put a minimum of three or four ground control points around the perimeter of your job site
- Place a CHP around your job site
3. Add a Control Point to Existing Maps
Working hand in hand with professional surveying means creating a control point from a calculated coordinate can be simple.
Using an expert’s help will also simplify copying and pasting the calculated value into the existing workspace with reference data.
The workspace may as well have template layers. Those layers may not have data at this stage, but you can use it in the field to ascertain proper information gets exported as a file.
4. Choose Location Where to Place GCP
If you want to survey a perfect square, choosing a location where you can place ground control points will be simple.
But things are seldom – it is that simple. This is why when choosing a location where to place GCP, you might want to consider tips, like staying low and being keen when choosing naturally occurring GCPs.
5. Measure the Location
It is imperative to measure ground control points as the center of every GCP. In order to accomplish this, you will use either a PPK (Post Processing Kinematic) or RTK (Real Time Kinematic) GPS receiver.
Leica and Trimble products are mostly used for accurate GPS measurements. Lower-cost and newer alternatives have come up in the market too. Working with a surveyor to measure the location of GCP can be an option as well.
For a simple job site assessment or quick survey, consider installing a survey control point temporarily for the task. But for a recording survey, knowing the basics will be best to know how to control point surveys.