N and T Geomatics

17/07/2026

Still at it, detail survey

12/07/2026

Leveling Staff Reading

A leveling staff is used with a dumpy level or automatic level to measure ground elevation. The correct staff reading is taken at the point where the middle horizontal crosshair intersects the staff. This reading is then used to calculate the Reduced Level (RL) accurately for surveying and construction work.

11/07/2026

Detail survey contouring

28/06/2026

RTK Survey – How It Works

RTK (Real-Time Kinematic) Survey is a high-precision GNSS surveying method that provides 1–3 cm accuracy in real time. A base station receives satellite signals and sends correction data to a rover receiver, allowing the rover to calculate an extremely accurate position instantly. RTK is widely used for construction layout, road projects, topographic surveys, and land mapping.

28/06/2026

Hillside RL Calculation (Rise & Fall Method)

The Rise & Fall Method is used in leveling to calculate the Reduced Level (RL) of points on sloping ground.

Formula: RL(new) = RL(previous) + Rise − Fall

If BS > FS, the ground rises.

If FS > BS, the ground falls.

In this example: BS = 2.10 m, FS = 0.85 m.

Rise = 2.10 − 0.85 = 1.25 m.

Therefore, RL(B) = 245.50 + 1.25 = 246.75 m.

This method ensures accurate elevation calculations for surveying, road, and hillside construction projects.

22/06/2026

Our website is up and running for your perusal.

N&T Geomatics is a professional land surveying and geospatial services company specialising in Cadastral Surveying, Geographic Information Systems (GIS), and Photogrammetry.

22/05/2026

Total Station Surveying Methods

Total station surveying uses an electronic instrument to measure angles, distances, and coordinates with high accuracy. Common methods include radiation, traverse, resection, offset, remote elevation, and stakeout methods for mapping, construction layout, and land surveying. It improves survey speed, precision, and digital data recording in modern civil engineering projects.

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22/05/2026

Hillside Surveying RL Calculation Using Theodolite

In hillside surveying, a theodolite is used to measure vertical and horizontal angles on sloping ground. Reduced Level (RL) calculation helps determine the height difference between points.

Basic Formula:

HI = RL of Benchmark + Back Sight (BS)

RL = HI − Staff Reading

Process:

1. Set the theodolite on stable ground.

2. Take a Back Sight (BS) reading on the benchmark.

3. Calculate Height of Instrument (HI).

4. Take Intermediate Sight (IS) or Fore Sight (FS) readings on hillside points.

5. Calculate RL of each point.

Uses:

Road construction

Hill cutting and filling

Contour mapping

Bridge and retaining wall projects