How to set up survey control on large construction projects in Riyadh
Every coordinate on a construction site is only as good as the control network behind it. This guide explains how a survey control network is designed, observed, checked and maintained on large projects in Riyadh and across Saudi Arabia.
IllustrationThe short answer
Establish a primary network of stable monuments, observed with static GNSS and tied to the Saudi national reference frame (KSA-GRF17), adjust it by least squares, then densify it with total station traverses and precise levelling close to the work areas. Re-check the points regularly, above all after earthworks or dewatering, and keep a written control report.
Why survey control comes first
Setting-out, as-built checks, laser scanning and monitoring all take their positions from the control points. An error in the control network is copied into every element that is set out from it, so it is the cheapest place to get things right and the most expensive place to get them wrong.
On large projects several contractors and survey teams often work at the same time. A single, documented network is what lets their work fit together at the interfaces.
Step by step
A typical workflow for a large site in Riyadh:
- Design the network: place primary points outside the zone of excavation and heavy traffic, with clear sky view for GNSS and lines of sight between neighbouring points for total stations.
- Monument the points: concrete pillars or anchored survey markers that will not move with the ground, protected and clearly labelled.
- Observe the primary network with static GNSS: long sessions on every point, with redundant baselines, connected to the national reference frame KSA-GRF17 published by the General Authority for Survey and Geospatial Information (GEOSA).
- Adjust the observations by least squares and check the residuals; reject or re-observe any point that does not fit.
- Define the project grid: Riyadh lies in UTM zone 38N; many projects also use a local grid with a scale factor so that grid distances match distances on the ground.
- Densify: secondary points near the work areas by closed total station traverses, and heights by precise digital levelling from the project benchmarks.
- Issue a control report with coordinates, heights, accuracies, descriptions and photos of each point, and share it with every party working on site.
- Maintain: re-observe at set intervals and after any event that could disturb a point, such as nearby excavation, dewatering or heavy plant movement.
Common mistakes
- Points placed too close to the excavation, where settlement moves them unnoticed.
- A network with no redundancy, so a disturbed point cannot be detected.
- Mixing grid and ground distances, which creates scale errors over long alignments.
- Each contractor running its own control instead of one shared, documented network.
- No re-checks after earthworks, dewatering or long gaps in the programme.
How YAZ Development helps
YAZ Development provides survey control networks as part of its surveying and construction geomatics services in Riyadh and across Saudi Arabia, using Leica and Trimble GNSS receivers and Leica total stations, and supplies equipped survey teams to contractors. YAZ provided survey control on projects including King Fahd Stadium, King Salman Park and the Dairab Road project.
Last updated: 20 October 2026 · YAZ Development
Common questions
What reference frame should a project in Saudi Arabia use?
Most projects tie their control to the national reference frame KSA-GRF17, published by the General Authority for Survey and Geospatial Information (GEOSA), and then work in UTM or a local project grid defined from it. The project specification decides the exact grid.
How often should survey control points be checked?
At the intervals set in the project survey plan, and in addition after any event that could move a point: nearby excavation, dewatering, piling or heavy plant. Points used daily for setting-out are usually checked against each other at every setup.
Can RTK GNSS replace a control network?
RTK is fast for setting-out and topographic work, but it should still be checked against a network of known points. Precise structural setting-out and monitoring are normally done with total stations from fixed control.
More guides
- Construction surveying and setting-out for infrastructure projects in Saudi Arabia Construction surveying transfers the design onto the ground and checks the result: it covers control checks, setting-out of alignments and structures, levels, as-built surveys and survey records for quality control.
- How accurate is 3D laser scanning for construction, and how to choose a provider Modern terrestrial scanners measure single points to a few millimetres at short range, but project accuracy depends on registration, ties to survey control, range and surface.
- How structural monitoring keeps excavations safe on Saudi infrastructure projects Before digging starts, a baseline is measured on the retaining walls, the ground and nearby buildings.
- The benefits of GIS in large-scale urban development in Saudi Arabia GIS gives a large development one shared, location-based source of truth: survey, drone, utility, design and asset data in a single coordinate system.
- Scan to BIM vs a traditional measured survey: which one does your project need? A traditional measured survey records selected points and dimensions and suits simple spaces and small scopes.
- GPR utility detection before excavation: how it works and what to expect A utility survey starts with existing records, then sweeps the area with electromagnetic locators for metallic services and scans it with GPR in a grid to find metallic and non-metallic pipes, ducts and voids.
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