Find the best house site on your land

Who uses this

• Rural and lifestyle-block owners. Decide where the house, shed or glasshouse should go.
• Buyers. Check that a large block actually has a buildable, sunny platform on it.
• Designers and solar installers. Short-list candidate sites before a site visit.

When to use it

• Finding candidate house sites or building platforms on a rural block.
• Locating flat, sunny ground for a shed, a glasshouse, an orchard block or solar panels.
• Screening a large property down to the few places worth walking.

Which tool for your job

Find Matching Areas is one step in a bigger question. These are the jobs it helps with, and the tools that go with it.

How to use it

1. Select a property, draw an area or upload a boundary.
2. Pick a starting point (House site, Solar panels, Orchard or vineyard, Effluent field, Shed pad) or set the conditions yourself.
3. Adjust the numbers. The first three conditions are always on; wetness and room to build are under More conditions.
4. Run analysis. Matching ground is green, everything else grey. The panel shows how much ground each condition removed.
5. Choose Use as area on a patch, then open Cut & Fill, Sunlight, Viewshed or a Property Report to look at just that patch.

Step by step: Mt Iron, Wānaka

We look for ground inside the Mt Iron reserve that is gentle enough to build on and still gets winter sun, then narrow it to real house sites and size the earthworks on the best one.

What it showed

• The funnel shows which condition does the damage. Slope removes the most, and the platform test then cuts what is left from 24 % to 5 %: there is gentle, sunny ground, but little of it stays gentle over a whole 20 m square.
• Use as area is the link between tools: find the spot with one, then size it, check its sun or view with the next.
• This is a terrain filter. Zoning, access, services and ground stability are separate questions.

Screenshots from NZ Elevation Tools. Aerial imagery from LINZ Basemaps. Sourced from the LINZ Data Service and licensed by Environment Southland, Otago Regional Council and Queenstown-Lakes District Council for re-use under the Creative Commons Attribution 4.0 International licence.

How it works

Every cell of the 1 m LiDAR bare-earth model is tested. Slope and facing direction come from the terrain; direct sun hours are modelled for 21 June by tracing the sun and checking whether terrain up to 3 km away blocks it.

Wetness uses the same topographic wetness index as the Wetness Map, ranked within your area, so "not in the wettest 20 %" leaves out the fifth of the ground where the shape of the land gathers the most water.

Room to build keeps only ground where a square platform of the chosen width fits with every cell inside it passing. A long thin strip can pass every other test and still have nowhere to put a house; this removes it.

A cell matches only when every active test passes. Flat ground has no facing direction, so it only passes that test when any way is chosen.

Reading the results

What each condition leaves lists the ground remaining after each test in turn. The condition that removes the most is highlighted: relax that one first if too little is left.

Show ground that misses by one condition adds amber for ground that fails exactly one test, which is where a small change would add the most.

Largest patches lists the five biggest matching patches. Use as area makes one of them the selected area for any other tool.

Winter sun is modelled on bare ground, so a patch shaded by a shelterbelt or a neighbour’s house can still show as sunny.

Limits and warnings

• Terrain criteria only. Not a check of zoning, setbacks, geotechnical stability, access, services or flood hazard.
• Presets are starting points, not rules. Check them against your own plans and the council’s.
• Areas up to 12 km across. Larger areas are sampled more coarsely, so small platforms can disappear; select a smaller area for detail.
• Where 1 m LiDAR has not been flown the tool falls back to the national 8 m elevation model, and the result says what share came from the fallback. The 8 m model was interpolated from 20 m map contours and is not fit for site-scale decisions.

Data and attribution

Results come from the LINZ national 1 m LiDAR bare-earth elevation model, read in your browser, with the national 8 m model filling any gaps. Tools that use the surface model (Sunlight, Viewshed, Object Heights) read the matching LiDAR surface tiles.

Elevation and cadastral data is sourced from the LINZ Data Service and licensed for re-use under the Creative Commons Attribution 4.0 International licence. Copyright in each LiDAR survey belongs to the body that commissioned it — a regional or district council, Waka Kotahi, NIWA and around thirty others — rather than to LINZ, which hosts and processes the national dataset. Every file exported from this site names the licensors whose surveys cover the area, and anything you publish from those files carries the same attribution requirement. See https://www.linz.govt.nz/products-services/data/licensing-and-using-data/attributing-elevation-or-aerial-imagery-data

Questions

Related

Neighbouring tools

• Slope & Aspect — Maps how steep every part of your area is and which compass direction each face points, with a full breakdown of slope classes and aspect shares.
• Sunlight — Models hours of direct sun across a site on any day of the year, with shadows from terrain up to 3 km away and, where LiDAR has been flown, from trees and buildings.
• Cut & Fill — Estimates how much earth would be cut and how much filled to level your area to a flat platform, at a height you set or at the height that balances the two.
• Saved Properties — Keeps up to five places in your browser and compares their elevation, slope, winter sunlight and drainage side by side.

Guides

• Slope Maps for Building on Sloping Land