NSPS CST Level IV - Office Track
Office Track tests advanced office production: records research, boundary resolution, coordinate systems, least-squares adjustment, mapping and plat standards, and QA of deliverables. Level IV questions emphasize defensible decisions and traceable computations.
Core office rules
- Research first: deeds, plats, easements, highway plans, and control records. Build a chain of title and compare calls; resolve conflicts by evidence, intent, and senior rights-not by CAD convenience.
- Boundary versus topographic or ALTA/NSPS work: boundary resolution is legal and evidence based; ALTA/NSPS surveys add Table A requirements and title/adjoining-owner issues.
- Coordinate systems: state plane/NSRS, datum and epoch, units, convergence, and scale. Apply the combined factor correctly.
- Adjustments: least squares requires realistic weighting; inspect residuals and standardized residuals; never hide a blunder with a low-weight observation.
- Deliverables: layer and name standards, metadata, point/line connectivity, closure, and independent check plots.
Worked example
A ground distance is 500.000 ft. The project combined factor (grid/ground) is 0.999700. Grid distance = 500.000 × 0.999700 = 499.850 ft. To go from grid to ground, divide by 0.999700. If a CAD line was drawn as 500.000 ft on grid, it is 0.150 ft too long on the ground-small, but significant at a property corner. Record the factor and source in the project metadata.
Traps
- Applying the scale factor in the wrong direction.
- Mixing state plane epoch or grid coordinates with ground coordinates.
- Treating a plat line as a boundary without deed and evidence analysis.
- Ignoring easements or junior/senior rights.
- Reporting least-squares coordinates without residual review.
- Omitting metadata so another surveyor cannot reproduce the result.