Design baseline
Freeze the issued-for-construction geometry — alignment, levels, structural setting-out — with a revision register, so there is one thing to certify against.
Ghana construction assurance / Capability 04
BuildGhana™
See divergence while it is still cheap to correct.
Independent design-versus-as-built assurance, progress measurement and funder-ready evidence for infrastructure delivery.
DecisionCertify · hold · escalate
ControlMeasurement before payment
CoverageAll 16 Ghana regions
Design vs as-built layer / Ghana Live
Design · measured · deviation
Element / tolerance / measured deviation / disposition
Operating model
Built as drawn?
Prove it, element by element.
Ghanaian infrastructure is paid on certificates, and certificates are signed against drawings. BuildGhana tests whether the measurement behind a certificate can actually carry it — before retention is released and the defects period starts running.
Control audit
Test the project survey control before trusting any deviation. Legacy War Office 1926 coordinates and GNSS work disagree unless the transformation has been observed and published.
Reality capture
Measure the works as built — total station, GNSS, LiDAR or controlled UAV — matched to the tolerance each element has to meet.
Deviation computation
Compare measured geometry to design, report the signed deviation per element, and separate datum error from construction error.
Disposition
Every out-of-tolerance item is accepted, reworked or redesigned by a named decision-maker, with the reason recorded.
Certification evidence
Issue the deviation register, hold-point releases, control records and measurement statement that a funder or auditor can follow end to end.
Measurement layers
Every method states
what it cannot prove.
Total station traverse from fixed control
Discrete points only; slow over long chainage.
Resolves tolerances above ±10 mm with 95% coverage.
GNSS RTK from a base or CORS
Fast over corridors; degrades under canopy and near structures.
Resolves tolerances above ±30 mm with 95% coverage.
Terrestrial or mobile LiDAR
Dense surfaces and structural geometry; needs registered control.
Resolves tolerances above ±16 mm with 95% coverage.
UAV photogrammetry with surveyed ground control
Whole-site surfaces, volumes and progress; GCAA authorisation required.
Resolves tolerances above ±60 mm with 95% coverage.
UAV photogrammetry, onboard GNSS only
Useful for visual progress; not defensible for level or position claims.
Resolves tolerances above ±300 mm with 95% coverage.
Tape, level and staff records
Traditional site record; rarely traceable back to a datum.
Resolves tolerances above ±100 mm with 95% coverage.
Service boundary
BuildGhana measures and evidences deviation. It does not certify works, approve payment or accept structural adequacy. Certification stays with the supervising engineer, structural judgement with a qualified engineer registered in Ghana, boundary and control certification with a licensed surveyor, and payment with the employer.
Why control comes first
Much of Ghana's engineering and cadastral control sits on the War Office 1926 ellipsoid and the Ghana National Grid, while site GNSS reports ITRF/WGS84 coordinates. Mixing them without an observed transformation produces apparent deviations of metres that are datum error, not construction error. Every assurance case here is tested against the control you actually hold.
BuildGhana™ assurance desk / Ghana
Measure what was built.
Certify only what is proven.
Assurance confidence25/ 100 · High exposure
Within tolerance90.8%
Value at riskUS$385k
Evidence readiness53%
Measurement uncertainty±90 mm
01 / Contract and works
What is being certified, and under which form
02 / Element classes under assurance
Each tolerance is tested against what your survey can actually resolve
03 / Measurement chain
Control, capture and design baseline
Evidence basis
No files, captures or land records are on file for this site yet. The chain below is what you state, not what is evidenced. Upload the design set, control record, as-built survey and check register in the data studio and this case scores from them instead.
GNSS RTK from a base or CORS: Fast over corridors; degrades under canopy and near structures. Stated 1σ positional uncertainty 15 mm.
War Office 1926 / Ghana National Grid, transformation untested: Systematic offsets of metres are common when the transformation is assumed rather than tested.
2D CAD drawings with coordinate schedules: Comparison depends on interpreting drawings into geometry.
04 / Funder evidence pack
What a disbursement review will ask for
Issued-for-construction design baseline with revision registerIn place
Primary control record, adjustment report and surveyor's certificateOutstanding
Instrument calibration certificates for the capture methodIn place
As-built survey covering the certified worksOutstanding
Tolerance check register with design, measured and verdict per itemIn place
Independent check survey and reconciliation statementOutstanding
Deviation register with disposition (accept, rework, redesign)In place
Signed hold-point releases against the inspection and test planIn place
05 / Inspection and test plan
Hold points still to be released
Horizontal alignment / setting out
Not provable — ±90 mm measurement against a ±50 mm tolerance. Tolerance-to-uncertainty ratio 0.56.
Release authority: Ghana Highway Authority · supervising engineer
Formation and subgrade level
Not provable — ±90 mm measurement against a ±25 mm tolerance. Tolerance-to-uncertainty ratio 0.28.
Release authority: Supervising engineer · Ghana Highway Authority
Pavement layer thickness
Not provable — ±90 mm measurement against a ±10 mm tolerance. Tolerance-to-uncertainty ratio 0.11.
Release authority: Ghana Highway Authority materials laboratory
Drain and channel invert level
Not provable — ±90 mm measurement against a ±15 mm tolerance. Tolerance-to-uncertainty ratio 0.17.
Release authority: Department of Urban Roads · Hydrological Services
06 / Assurance action register
Resolve before the next valuation
Priority 01
Test the War Office 1926 to GNSS transformation before trusting any offset
Occupy at least three known Ghana National Grid stations with GNSS, publish the residuals, and adopt a project transformation. Until then, apparent deviations may be datum error rather than construction error.
Priority 02
Upgrade measurement for horizontal alignment / setting out
A ±50 mm tolerance cannot be proven with a ±90 mm method. Use total station or LiDAR observation from fixed control for this element class.
Priority 03
Upgrade measurement for formation and subgrade level
A ±25 mm tolerance cannot be proven with a ±90 mm method. Use total station or LiDAR observation from fixed control for this element class.
Priority 04
Upgrade measurement for pavement layer thickness
A ±10 mm tolerance cannot be proven with a ±90 mm method. Use total station or LiDAR observation from fixed control for this element class.
Priority 05
Upgrade measurement for drain and channel invert level
A ±15 mm tolerance cannot be proven with a ±90 mm method. Use total station or LiDAR observation from fixed control for this element class.
Priority 06
Raise as-built survey coverage before the next valuation
Only 45% of completed works has been measured. The unmeasured remainder is where retention and defects liability exposure accumulates.
Priority 07
Appoint an independent check surveyor
Deviation evidence produced solely by the contractor is routinely challenged at valuation and in dispute. Independent check observation makes the record defensible.
Priority 08
Reconcile re-measurement quantities to the as-built surface
Under a re-measured contract the paid quantity must follow the measured work. Tie earthworks and layer quantities to the surveyed surface, not the claimed one.
Build stage / the chain
Nothing here
stands alone.
BuildGhana™ answers “Does the built work match the design?”. It produces the deviation register and funder evidence pack — and that record is exactly what the next desk refuses to work without.
Feeds in
LandIntel™The land interest the works are certified againstTerraGhana™Design platform levels and earthworks baselineSubsurface Ghana™Proven service positions the as-built survey must clearSkyGhana™Dated capture epochs measured against the programmeInfraGhana™Certified quantities and hold points the element check is run against04 / now
BuildGhana™
Independent design-versus-as-built assurance, progress measurement and funder-ready evidence for infrastructure delivery.
As-built QADeviationFunder reporting
Connected intelligence
Evidence, research
and access.
The public evidence library and licensing catalogue stay connected to this capability. New published material appears here automatically.
From analysis to site
Brief one decision.
We resolve the ground.
Submit the assurance case for control verification, as-built capture, deviation computation and independent check. We return the measurement plan, hold-point schedule, dependencies and the evidence standard a funder will accept.