Getting Tasmanian LiDAR contours and cadastre into Civil 3D and QGIS

To set up a Tasmanian site in Civil 3D, QGIS or ArcGIS, you need three things in the right coordinate system: an elevation surface (a DEM or TIN) to build a design surface from, contours to read the slope, and the cadastre so the lot boundary sits where the survey says it does. Tasmania's statewide LiDAR, the LIST (Land Information System Tasmania) cadastre and the Tasmanian Planning Scheme overlays are all public, but they come in different formats and different projections, and the order you load them in decides whether they line up. This walkthrough runs the task from address to imported surface for a lot in Hobart, Launceston or Devonport.

Work in GDA2020 MGA Zone 55 for almost every Tasmanian site, and use AHD (Australian Height Datum) for heights. The one exception is western King Island, which sits west of the 144 degree meridian: it is commonly mapped in Zone 55 with the rest of the state, but GPS and some survey data there comes out in Zone 54. Check the zone each source dataset is actually supplied in and transform from that, rather than assuming Zone 55. Fix the projection first and most of the alignment problems below never appear.

Step 1: Confirm the lot and the datum before you download anything

Start from the property address or the title reference and confirm the parcel on the LIST map. Note the plan number and lot identifier so you can match the exported polygon later. Decide your working coordinate system now: GDA2020 MGA Zone 55 (EPSG:7855) for eastings and northings, AHD for elevation.

Gotcha: older Tasmanian datasets and some survey plans are in GDA94 MGA Zone 55 (EPSG:28355), not GDA2020. The two differ by roughly 1.8 metres on the ground in Tasmania. That is enough to throw a boundary off a fence line. If you mix a GDA94 cadastre with a GDA2020 surface, everything looks fine until you scale in. Read why the coordinate system matters before you assume the files agree.

Step 2: Choose contours or a DEM for the elevation

Decide what you need the elevation for. If you want to read slope and drainage lines for a desktop review, vector contours are faster to load and easier to label. If you are building a design surface to model earthworks or a driveway grade, you want the raster DEM or a TIN, because contours discard the data between the lines.

Dataset	Format it comes out in	Use it for
Contours	DXF, Shapefile, GeoPackage, KMZ	Reading slope, drainage, early plans
DEM (elevation grid)	GeoTIFF raster	Building a surface, cut and fill, catchment
TIN surface	DXF only	Dropping straight into a Civil 3D surface

Gotcha: do not build a design surface from contours if the raster is available. Interpolating a surface back from contour lines reintroduces error the LiDAR already resolved. For the reasoning, see contours or DEM.

Step 3: Pick a contour interval that suits the terrain

Tasmanian sites range from flat reclaimed ground on the Hobart waterfront to steep dolerite slopes on the flanks of kunanyi / Mount Wellington and the hills behind Launceston. On a steep block a 1 metre interval turns into a wall of unreadable lines. On flat ground a 1 metre interval shows almost nothing.

As a starting point: 0.5 m on flat lowland lots, 1 m on typical suburban slopes, and 2 m on steep bushland blocks where you only need the shape. Generate the interval from the DEM rather than downloading a fixed one, so you can regenerate it if the first choice is too dense or too sparse.

Gotcha: the LiDAR ground model still carries small artefacts under dense vegetation, which is common on the treed slopes around Hobart. Very tight contours on a wooded block can show noise, not ground. Widen the interval before you assume the ground is that irregular.

Step 4: Export the cadastre in a format your software reads cleanly

Pull the lot boundary and the surrounding parcels. For Civil 3D, DXF drops the boundary straight onto a layer. For QGIS or ArcGIS, GeoPackage or Shapefile keeps the parcel attributes (plan number, area, lot ID) attached, which DXF loses.

Gotcha: Shapefile truncates field names to ten characters and has no single-file structure, so a Shapefile is really four or more files that must stay together. GeoPackage is one file, keeps full attributes and full field names, and is the better choice for QGIS and ArcGIS. Use DXF only where you specifically need geometry in CAD. This is covered in more depth in getting cadastre into Civil 3D and QGIS.

Step 5: Add the planning and hazard overlays for context

For a desktop review, load the zone and the hazard overlays from the planning scheme in force for that municipality. Where the Tasmanian Planning Scheme is in effect, read it together with that council's local provisions schedule; in Kingborough, use the Kingborough Interim Planning Scheme 2015 instead. Take the landslip layer from the scheme's own overlay source, since the mapped extent differs from council to council. On sloping Tasmanian sites the landslip hazard overlay is the one to check: it flags land where movement is a known risk and can trigger a geotechnical assessment before development. Much of the steeper ground around Hobart, the Tamar valley slopes near Launceston and parts of the north-west coast sits inside a landslip hazard band.

Gotcha: the overlay is a planning trigger, not a site verdict. It tells you an assessment may be required; it does not measure the stability of your specific lot. Export it as a KMZ or GeoPackage to sit under the cadastre and read the boundary against the mapped hazard.

Step 6: Import in the right order and check the alignment

Load the DEM or TIN first, then the contours, then the cadastre on top, then the overlays. In Civil 3D, bring the TIN in as a surface and the DXF cadastre onto its own layer. In QGIS or ArcGIS, set the project CRS to EPSG:7855 before you add a single layer, so everything draws in a common frame. That is display only: check each layer's own source CRS, and reproject or export the data itself to EPSG:7855 before you edit it, measure off it, run analysis on it or hand it to anyone else.

Gotcha: if the cadastre lands offset from the surface by a metre or two, you have a GDA94 versus GDA2020 mismatch (Step 1), not a bad download. Reproject the offending layer rather than nudging it by hand. The full list of import traps is in eight mistakes importing site data.

Step 7: Sanity-check before you design on it

Spot-check two or three known elevations against a benchmark or a survey mark, confirm the lot area matches the title, and confirm the boundary follows the features you expect. A desktop surface built from LiDAR is right for feasibility, grading concepts and early set-out. It is not a substitute for a boundary survey or a geotechnical site investigation, and on a landslip-overlay lot the field assessment still has to happen.

Once those checks pass, you have a Hobart, Launceston or Devonport site set up in the correct datum with elevation, contours, cadastre and overlays that agree with each other, ready for the first design model.

You can export site data for any address in Tasmania in these formats, or see a sample export to check the structure before you download.

LayeredGeo lets you download site data for Queensland, New South Wales, Victoria, South Australia, the ACT and Tasmania - contours, cadastre and more - in DXF, Shapefile, GeoPackage, KMZ and raster formats, ready for Civil 3D, QGIS and ArcGIS.

About this article. Published by LayeredGeo. It is general information about how property and ground conditions are assessed in Australia, not engineering, planning, legal or financial advice, and it is not specific to any property. Check anything that matters against the source dataset or a suitably qualified professional before you rely on it. If you spot something wrong, tell us at hello@layeredgeo.com.au and we will fix it.

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