Terrain · Select a property, draw a box or polygon, or upload a boundary
Slope map: how steep is my section?
This slope map shows how steep every part of a New Zealand section is, from the LINZ LiDAR elevation model, and which way each face points. The panel breaks the site into slope classes, so "how steep is my section" gets a number instead of a guess.
Slope decides whether a site is easy to build on, where retaining and cut and fill will be needed, and whether a council will ask for geotechnical input. Aspect decides how much winter sun the ground gets.
Free to run · pay to download
See the full result on the map free, with no account. Download the slope or aspect grid as a GeoTIFF in NZTM2000 with a pass: NZ$49 for 7 days or NZ$299 for 12 months, one-off, GST included, not a subscription. Every download on the site is included while the pass lasts.
Who uses this
- Buyers. Know how much of a section is actually buildable before making an offer.
- Architects and consent applicants. Describe the site slope for a design brief or a consent conversation.
- Farmers and growers. Find the faces too steep for machinery or prone to erosion.
When to use it
- Checking whether a site is buildable and where earthworks or retaining will be needed.
- Assessing pasture, orchard or vineyard ground for sun and machinery access.
- Answering a building consent or resource consent question about slope.
Which tool for your job
Slope & Aspect is one step in a bigger question. These are the jobs it helps with, and the tools that go with it.
If you’re working on solar panels and sun
Where will panels, a glasshouse or a deck get the most sun?
- 1.Sunlight — Hours of direct sun on any date, with terrain shadows from up to 3 km away. Start with the shortest day.
- 2.Slope & Aspect (this tool) — The aspect view shows which faces point north, and the slope view how steep the mounting ground is.
- 3.Find Matching Areas — Highlights the ground that is flat enough, faces the right way and clears a minimum of winter sun, all at once.
- 4.Object Heights — Tree and building heights, to spot shelterbelts that will shade the array.
If you’re working on choosing a house site
Where on this block should the house go?
- 1.Find Matching Areas — Narrows the block to the patches that are flat, sunny and facing the right way.
- 2.Slope & Aspect (this tool) — Shows where the ground is easy to build on and where retaining will be needed.
- 3.Sunlight — Checks winter sun on the candidate platform, hour by hour.
- 4.Cut & Fill — Estimates the earthworks to level the platform before you ask for quotes.
- 5.Viewshed — Shows what the house will see and who will see it.
- 6.Compare Quotes — When you know what you want, sends the job to up to 3 local pros to quote.
If you’re working on farming, orchards and planting
Which ground suits which use?
- 1.Slope & Aspect (this tool) — Machinery limits and erosion-prone faces.
- 2.Sunlight — Frost pockets and shaded faces in winter.
- 3.Wetness Map — Wet-tolerant planting in the blue, drought-tolerant on the tan.
- 4.Landforms — Exposed ridges, sheltered hollows and well-drained spurs.
How to use it
- Select a property, draw an area or upload a boundary.
- Run the analysis. Switch between the Slope and Aspect views in the panel.
- Read the class breakdown in the panel, or download the slope or aspect grid as a GeoTIFF in NZTM2000 for GIS. Downloading needs a pass.
Step by step: Mt Iron, Wānaka
We map slope across Mt Iron and the suburbs around it.
What it showed
- Under 10° is easy building ground; 10–20° usually means cut and fill or a split-level house; over 25° calls for geotechnical advice.
- Switch to the aspect view to see which faces point north.
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
For every terrain cell the tool fits a plane through the eight surrounding cells of the bare-earth grid read from the LINZ elevation tiles. The tilt of that plane is the slope, in degrees; the downhill direction is the aspect, as a compass bearing.
Slope classes and aspect sectors are then tallied as shares of the analysed area.
Reading the results
Under 10 degrees is generally easy building ground. Ten to 20 degrees usually means cut and fill or a split-level design. Over 25 degrees expect geotechnical input.
The flat share is ground too level to have a meaningful aspect, and is reported separately.
North-facing slopes get the most winter sun in New Zealand; south-facing slopes the least.
Limits and warnings
- Areas up to 12 km across; large areas are sampled more coarsely, which smooths out short steep banks.
- Where 1 m LiDAR has not been flown, the LINZ elevation tiles hold the national 8 m elevation model instead. It was interpolated from 20 m map contours and is not fit for site-scale decisions. The on-map result does not say which one it read: Data Here shows whether LiDAR covers a spot.
- Slope is of the bare ground. Retaining walls, buildings and vegetation are stripped out of the elevation model.
Compare quotes without ringing around
Slope & Aspect gives you a fast, indicative answer. When the job needs pricing, designing or signing off, getting quotes usually means calling around and explaining the same site over and over. Instead, run the tool on your site and choose Compare quotes under the result. Describe the job once and we’ll send it to up to 3 local geotechnical engineers, with an aerial map of the site, a Google Earth file and your results attached, so they can price it properly from the start. They quote you directly. It’s free and there’s no obligation.
Data and attribution
Heights come from the LINZ elevation tiles: LINZ’s national bare-earth elevation model (LiDAR where it has been flown, the 8 m model elsewhere), stored in 0.1 m steps, read in your browser at the finest zoom that fits the area: cells of about 0.5 m on a small area, coarser on a larger one. Over the sea the tiles read 0 m; they hold no seabed.
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
What slope is too steep to build on in NZ?
As a rough guide, under 10° is easy building ground, 10–20° usually means cut and fill or a split-level design, and over 25° expect a geotechnical report. Your council's district plan and building consent requirements set the actual rules.
Can I use this slope map for a building consent?
It helps you understand the site and brief a designer. Most councils want slope shown on surveyed plans for the consent itself.
Can I download the slope map?
Yes. The slope or aspect grid downloads as a GeoTIFF in NZTM2000 for QGIS, ArcGIS or any GIS, with slope in degrees or aspect as a compass bearing in every cell. Running the analysis and saving a PNG of the view are free; the GeoTIFF needs a pass.
Ready to try it?
Open Slope & Aspect on the map →Free to use, no account. Runs in your browser on LINZ open data. Downloading the results needs a pass: see prices.
Missing something you need? Suggest a feature or ask about custom work.