| S.No. | Field / Checkpoint | Reference | Status |
|---|---|---|---|
| A. CONTROL POINT NETWORK | |||
| A1 | Reference datum — GTS / city grid / project-specific Acceptance: Documented | Per project survey contract | OK NC NA |
| A2 | Control point ID + coordinates (E, N) + RL + monument type Acceptance: Permanent monument | Per project network | OK NC NA |
| A3 | Established by — surveyor + date + instrument used Acceptance: Calibrated instrument | DGPS / Total Station | OK NC NA |
| B. VERIFICATION | |||
| B1 | Inter-point distance + bearing checks Acceptance: Per accuracy class | Closure ± 10mm + 5 PPM (Total Station) | OK NC NA |
| B2 | Witness mark + photo + protection (boundary stone) Acceptance: Per drawing | Permanent + visible | OK NC NA |
| C. USAGE LOG | |||
| C1 | Date + activity + surveyor + readings taken Acceptance: Per activity | Daily log | OK NC NA |
| C2 | Annual re-verification + recovery if disturbed Acceptance: Verified | Per project standards | OK NC NA |
Construction surveying establishes a network of survey control points — known coordinates (x, y, z) on the ground that serve as references for laying out all building features. The Control Point Register is the master log of these points: identification, coordinates, accuracy, monumenting (how marked), date of establishment, and verification history.
Without a maintained register, control points get lost, disturbed, or never properly recorded. Subsequent surveying / setting out has no reliable baseline → cumulative errors → buildings out of alignment with neighbours, services missing target chambers, parking strips offset from drawings.
For major infrastructure projects (highways, metros, large layouts), survey control is the absolute foundation. IRC SP 19:2001 (Manual on highway surveys) mandates documented control networks for all road projects.
Per-control-point entry: - Point ID (sequential or descriptive — CP-01, BM-Stadia-North) - Coordinates (typically UTM x, y, z) and / or chainage + offset for linear projects - Datum reference (WGS-84 / Indian Geodetic Datum) - Type (primary / secondary / temporary) - Monumenting (concrete pillar, steel plug, painted X) - GPS / total station baseline used - Accuracy (mm or m) per measurement protocol - Date established + surveyor - Verification cycles (annual / per major construction phase) - Status (active / disturbed / re-established)
Typical control point networks: - Primary control: 3-5 points; high accuracy (GPS / GNSS); permanent monumenting - Secondary control: 10-20 points per site; medium accuracy; semi-permanent - Temporary control: 50+ points; for daily setting out; concrete-cast or stake markers
Verification: monthly during construction; immediate re-survey after major earthwork / blasting / monsoon events.
1. Insufficient density — control points too far apart; high precision in setting-out impossible. 2. Lost / disturbed points — bulldozer / vehicles damage monumenting; not detected until reused. 3. No verification history — assumed coordinates correct; cumulative drift undetected. 4. Wrong datum — different surveyors use different datums; inconsistent results across project phases. 5. No QA on initial survey — first survey errors propagate everywhere; impossible to correct retroactively. 6. No archive — when surveyor changes or project closes, historical data lost. 7. No backup copies — primary control monumenting destroyed; no backup network.
Companion formats: - Total Station Reading Sheet (FMT-SUR-003) — daily survey output - Cross Section Format (FMT-SUR-005) — cross-sectional survey - Setting Out / Line Out Register — for building corners + axes - Survey calibration certificates — for equipment accuracy verification
Standards + practices: - IRC SP 19:2001 — Manual on Highway Surveys - IS 1080:1985 — Code of practice for design and construction of shallow foundations (requires site survey) - IS 13900:1993 — Code of practice for procedures for safe operation of mobile cranes - GPS standards: WGS-84 datum; Indian projects use UTM Zone 43-46 depending on region - Geodetic Survey of India — primary geodetic reference network