Find the ground elevation at any point in New Zealand

Who uses this

• Owners and plumbers. Work out the fall from a tank to the house.
• Surveyors. Sanity-check a level against the national model.

When to use it

• You need a spot height for a floor level, a tank, a pump or a survey check.
• You want to confirm the height difference between two places quickly.
• You need a handful of spot heights in a spreadsheet, a GIS or a CAD drawing.
• You want a grid of spot heights over a section or a building site, for a level plan or a CAD surface.

Which tool for your job

Point Elevation 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. Open Point Elevation and click the map. The point is numbered on the map and listed in the panel with its elevation, coordinates and cell size.
2. Click again to add more points, up to 200. Remove one with its ×, or Clear all. The list stays while you pan, zoom, switch to 3D or use another tool.
3. Download the list as CSV, GeoJSON or DXF. Downloading needs a pass. Use Elevation Profile for a whole line.
4. For a grid, switch to Grid in an area, choose the area (a parcel from the Property tool, a box, a polygon or an uploaded boundary) and a spacing of 1, 2, 5, 10 m or any other you type. The panel shows how many points that makes before anything is read; a grid is limited to 50,000 points. Read the heights, then download the grid. You can cancel a run part way.

Step by step: Mt Iron, Wānaka

We read three spot heights down the summit ridge of Mt Iron, then a 10 m grid over the whole reserve.

What it showed

• For a line of heights use Elevation Profile; for a whole file of points use Elevate a File.

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

The LINZ elevation tiles, which store bare-earth heights in 0.1 m steps, are read in the browser around the clicked coordinate at the cell size the panel shows. The height is interpolated between the four nearest cells so the value is not snapped to a grid.

The files hold the values in the list, unchanged: elevation to 0.1 m, longitude and latitude, NZTM2000 easting and northing, and cell size, with the source, height datum and LINZ attribution written inside. GeoJSON is WGS84 points with the height as Z; the DXF is NZTM2000 points at their heights, each with a text label; the CSV has both coordinate systems.

A grid is laid in NZTM2000 from the south-west corner of the area, rows from the south, and keeps the points inside the area, including points on its edge. Each point is turned into latitude and longitude and read from the same tiles, the same way, as a click there; on areas up to about 3.5–4 km across the cells are the same size too, so a grid point and a click at the same spot give the same height. The files keep each point’s NZTM position to the millimetre, so the spacing reads true.

Reading the results

Metres above the LiDAR vertical datum, which is close to mean sea level. Compare with a survey benchmark before using it for design levels.

Limits and warnings

• The panel shows the cell size read, not which survey a height came from: Data Here lists the LiDAR surveys at a point. Where no LiDAR has been flown, LINZ’s heights come from the national 8 m model, interpolated from 20 m map contours and not fit for site-scale decisions.
• Bare ground only. On a deck or a roof the value is the ground beneath it.
• A grid spacing finer than the cells read (about 1.8 m) adds points interpolated between the same cells, not more detail. Areas more than about 3.5–4 km across are read from coarser tiles; the panel and files give the cell size.
• Heights are indicative, not survey-grade. The tiles hold 0 m over the sea, so a point on water reads 0.0 m, flagged in the list: it is not a seabed depth. Outside the tiles a point is listed with no height and the reason.

Data and attribution

Heights come from the LINZ elevation tiles: bare-earth heights stored in 0.1 m steps, read in your browser at the cell size the panel shows (about 1.7–1.9 m in New Zealand). 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

Related

Neighbouring tools

• Terrain Stats — Summarises the minimum, maximum, mean and range of ground elevation across an area, with a chart of how much land sits at each height.
• Elevation Profile — Produces a cross-section of the ground along any line, with distance, total climb and descent, and gradient.
• Elevate a File — Adds accurate ground elevation to the coordinates in a GPX, KML, GeoJSON, JSON or CSV file you already have, replacing missing or noisy GPS altitude.

Guides

• Elevation Lookup for New Zealand