Surveying Glossary.

The official national reference framework used to measure ground heights, levels, and elevations across Australia. It is based on a calculated mean sea level assigned as 0.000 metres. Local councils and certifiers require your building levels to be recorded in AHD to guarantee your structures conform to local roof height restrictions and flood level policies.

The statutory New South Wales government board responsible for regulating the land surveying profession, managing formal registrations, and protecting public safety. Under state law, only individuals fully registered with BOSSI are authorized to locate, determine, or mark legal property boundaries.

A formal legal reporting procedure that measures an existing completed building and physical fences relative to your legal title boundaries. The resulting plan and report identify any structural encroachments or boundary line mistakes, providing the official mathematical proof required by banks for home loans and certifiers for final sign-offs.

A physical field marking service where a registered land surveyor calculates your true lot corners and drives high-visibility wooden pegs, survey pins, or nails directly into the earth. This shows your builders or fencing contractors exactly where your legal property lines run on the ground before physical work starts.

A specialized, legal branch of surveying focused entirely on defining, managing, and recording property boundaries, land shapes, and lot areas. Cadastral surveys are highly regulated and can only be executed by a NSW Registered Land Surveyor.

An older property plan or map that was drawn up by copying and combining historical land records rather than executing a fresh, electronic on-site field survey. Many pre-1936 land titles in Sydney rely on compiled data, which can often contain dimension mistakes or disagree with real-world fences.

An architectural planning layout that maps out the physical features of your land. It records ground slopes, terrain levels, notable trees, visible utility services, and existing buildings. This provides your architect or building designer with a clean digital foundation for drafting Development Applications (DA).

A specific compliance survey executed after a new concrete driveway crossover or public layback is poured. It takes millimetre-accurate measurements of the finished surface to prove to your local council's engineering team that the driveway gradients and crossfalls match safety codes and won't cause cars to scrape.

A legally binding right carved out over a specific section of a property title that allows an external party-such as a neighbour, a municipal council, or a utility provider (like Sydney Water)-to use that part of your land for a specific purpose (e.g., access driveways, electricity pillars, or deep stormwater drainage pipes). You are strictly prohibited from constructing permanent buildings over registered easements.

A serious legal error where a physical structure from one property builds over, hangs over, or crosses the legal boundary line onto a neighbouring allotment. Common examples include brick garage walls extending over lines, concrete driveways poured on a neighbour's soil, or roof gutters hanging over fences.

The lowest internal height or floor level of an underground drainage pipe, culvert, or stormwater pit. Measuring invert levels accurately during a survey is vital for civil engineers to guarantee that wastewater will flow downhill smoothly using natural gravity.

The formal legal and technical process of combining two or more adjacent pieces of land into one single lot under a brand-new title. It is the exact opposite of a land subdivision. It permanently erases internal boundary lines so a new home or commercial complex can be built legally across the old lines.

The central government registry responsible for managing and maintaining the official land titles, public property deeds, registered deposited plans, and ownership frameworks for the state of New South Wales.

A specific compliance audit that measures the internal physical volumes, partition walls, and water orifice plates of a newly constructed stormwater storage tank. The data is required to prove the property can safely hold and control the flow of heavy rainfall during storm events.

A complex legal procedure where a registered land surveyor mathematically re-establishes outdated, unreliable property borders, marks them on site, and registers a brand-new, modern map at the NSW LRS. This permanently updates public records and gives the owner a completely secure, state-guaranteed boundary framework.

A formal legal document that is lodged at the NSW LRS right alongside a final Plan of Subdivision or Consolidation. It is used to officially create, vary, or remove property restrictions, shared rights-of-way, and utility easements across the newly formed lots.

A mandatory civil engineering check where newly built drainage networks and tanks are measured post-construction. The real-world measurements are overlaid in a contrasting red colour directly onto the original approved engineering drawings to prove to council inspectors that the drainage functions safely exactly as designed.

A legal property division that splits a building into private internal cubic airspaces (like apartments, townhouses, or industrial units) while designating shared structures, main roofs, common driveways, and main garden blocks as common property looked after by an owners corporation.

The legal process of permanently splitting a single piece of land into two or more independent property lots where every owner has exclusive ownership of both the building and the ground below, with no shared infrastructure or ongoing body corporate fees.