Survey Reference System

In 2004, SLA introduced the Co-ordinated Cadastre system to replace the old land survey system. The new system defines property boundaries by co-ordinates, rather than bearings and distances.

Survey Control Network

SLA has established the land survey control network as the infrastructure to support survey work conducted by all Registered Surveyors. This allows all land lots in Singapore to be geographically linked to each other and to the whole of Singapore.

We maintain 2 types of survey control:

  • Horizontal Control Network
  • Vertical Control Network

Horizontal Control Network

There are two categories of horizontal control: Primary and Secondary control network. As a whole, they are known as the Integrated Survey Network (ISN).

The primary control network consists of about 70 points that are strategically located in Singapore, most of which are on top of HDB flats, to cover the entire area of the island.

The secondary control network comprises of more than 5,000 points, which are mostly found on the ground along major roads for easy access.

Vertical Control Network

The vertical control network consists of physical points on the ground known as Precise Levelling Benchmarks (PLBM). There are about 400 PLBMs located at 1 km intervals along major roads. PLBM information is used to determine heights of locations in Singapore.

You can gain access to horizontal and vertical control network information via Integrated Land Information Service (INLIS).

Positioning with Global Navigation Satellite System (GNSS)

SLA maintains a network of continuously operating satellite reference stations on the ground, known as Singapore Satellite Positioning Reference Network (SiReNT) . SiReNT is a nation-wide infrastructure established and maintained by SLA that supports real-time and post-processed high precision satellite survey and positioning applications. With SiReNT, the establishment of new control points is seamless and easy.

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