Every site plan, footing layout and concept drawing starts with the same line: the lot boundary. And in most offices it still gets there the slow way. Someone opens the state mapping portal, screenshots the parcel, traces it in CAD, and hopes the scale is right.
This guide covers where cadastral boundary data actually comes from in each state, why the official portals hand you a whole region instead of one lot, and how to get a single boundary as a DXF in metres in about ten seconds.
Where the cadastre lives, state by state
Each state maintains its own Digital Cadastral Database (DCDB). They all publish it, but almost all of them publish it in bulk.
| State | Source | What you get from the portal |
|---|---|---|
| QLD | QLD Globe / QSpatial | Whole-LGA or suburb clip as SHP, TAB, FGDB, KMZ, GPKG. No DXF. |
| NSW | SIX Maps / Spatial Collaboration Portal | Clip & Ship by rectangle as SHP or TAB. Map image export only from SIX Maps. |
| VIC | Vicmap Property via DataShare | Statewide or LGA extract, hundreds of MB. Some DXF only for Melbourne metro. |
| ACT | ACTmapi | Block Dimension Report as PDF. No vector export. |
| SA | SAPPA / Location SA | Map PDF, WFS for GIS users. |
| WA | Landgate / SLIP | Bulk cadastre via subscription or WFS. |
| TAS | LISTmap | Region extract as SHP. |
| NT | NT Atlas / NTLIS | WMS/WFS layers. |
The pattern is the same everywhere. The data is free or cheap, but it is packaged for GIS analysts working on a region, not for a draftsperson who needs one parcel by lunchtime. So the “cadastre download” step turns into a GIS conversion step: download, unzip, load into QGIS, filter to the lot, reproject, export to DXF, then check the units in CAD.
Why a screenshot trace is worse than it looks
Tracing a boundary from a portal image introduces three separate errors:
- Scale. Portal tiles are not at a known scale, so the traced polygon has to be rescaled to a measured dimension. Any error in that dimension propagates to every line.
- Bearing. Screen north is usually true or grid north depending on the portal, and the trace inherits whichever it was.
- Vertices. A curved or irregular boundary gets simplified to whatever the tracer could see at that zoom.
For a concept sketch this is fine. For anything that will be dimensioned, it is not.
The fast path: one lot, one DXF
PlanInsight generates a DXF for a single property from the state cadastre, already converted to metres. You search an address, the lot is identified against the title record, and the boundary is written to a BOUNDARY layer in a DXF R12 file that opens in AutoCAD, Civil 3D, BricsCAD, DraftSight and QGIS without a plugin.
You can try this without an account. The free property boundary DXF tool returns the boundary layer for any Australian address.
With an account, the same download includes the rest of the site data on separate layers:
BOUNDARYandPARCEL_LABEL(lot on plan text)BUILDINGandBUILDING_FILL(existing footprints)CONTOUR_INDEX,CONTOUR_MAJOR,CONTOUR_MINORwith elevation labelsWATERCOURSE,WATER_BORE, andWATER_BODYin NSW
Full layer list is on the features page. The file is in metres, centred on the lot, so it drops straight in with no unit conversion.
Things to know before you rely on it
Coordinates are local, not grid. The DXF uses a local metre origin at the lot centroid rather than MGA2020 eastings and northings. That makes it drop-in for a site plan, but if you are combining it with a survey in grid coordinates, move it to the surveyed control first.
The DCDB is not the boundary. Every state says this in its own words. NSW Spatial Services puts it plainly: the DCDB is not the point of truth for the legal property boundary. That is always the plan of survey. Cadastral data is graphical, and in rural areas the positional accuracy can be off by metres. Use it to scope and design, and get a registered surveyor to set out.
Check the surveyed status. The PlanInsight property record shows whether the parcel is surveyed or compiled. A compiled parcel is a stronger reason to be careful with the DCDB lines.
A workflow that takes minutes, not an afternoon
- Search the address. Confirm the lot on plan and land area match the title.
- Download the DXF. Pick the layers you need in the dialog.
- Open in CAD. Everything is in metres on named layers.
- Check the planning zone, overlays and any live DAs on the same property screen before you quote.
That is the whole job. The consulting engineers page walks through how geotechnical, civil and structural teams use this to scope a site before anyone leaves the office.