Elevation profile and gradient along any line

Who uses this

• Owners and designers. Check a driveway or a path meets the grade before it is drawn up.
• Farmers. Test a track, race or fence line.
• Walkers, runners and riders. Get the climb on a route.

When to use it

• Planning a driveway, a track, a pipe run, a fence line or a race.
• Checking the climb on a walk, a ride or a run.
• Seeing whether water will flow the right way along a proposed drain.

Which tool for your job

Elevation Profile 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 Elevation Profile and tap out the line, corner by corner. Undo removes the last point.
2. Finish the line. The profile chart appears in the panel.
3. Hover, tap or drag along the chart to read distance, elevation, gradient and position at any point; a marker follows on the map. Pointing at the line on the map moves the chart too, and with the chart selected the arrow keys step along it.
4. With a pass, download the profile as CSV, 3D GeoJSON or KML (WGS84), or a 3D DXF polyline (NZTM2000). Saving a picture of the chart is free.

Step by step: Mt Iron, Wānaka

We draw a cross-section from the houses at the foot of Mt Iron up over the top.

What it showed

• Hover, tap or drag the chart to read distance, height and gradient at any point, with a marker on the map. With a pass, download it as CSV, 3D GeoJSON, KML or DXF; a picture of the chart is free.

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 line is sampled at close, even spacing, plus every corner you placed, and the LiDAR bare-earth model is read at each sample, interpolating between cells. Ascent and descent ignore ups and downs of less than 2 m along the way, so terrain-model noise does not inflate the totals; whatever is still climbing or falling at the end of the line is counted, so ascent minus descent always equals the change from start to finish. Gradient at a point is rise over run between the samples either side of it.

Reading the results

Gradient is in percent: 10 % is 1 m of rise for every 10 m along. Driveways over about 16 % are hard for cars; 20 % is the usual council limit.

Total ascent and descent add up every climb and drop of 2 m or more, so a rolling line shows more climb than the difference between its ends. Smaller wiggles are treated as terrain-model noise.

Limits and warnings

• Lines up to 25 km.
• 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.
• Bare ground only. A bridge or a culvert shows as the valley beneath it.

Compare quotes without ringing around

Elevation Profile 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 earthworks contractors, 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

Related

Neighbouring tools

• Measure — Measures the length of a line you tap out on the map, corner by corner, as a flat map distance.
• Route Explorer — Finds a route from a start to a finish, through any stops you add, that favours gentle grades and stays under a maximum grade you set, offers a smoothed version of it, and shows both on the map and the elevation chart.
• Sightline — Checks whether one point is visible from another, and if not, where the view is first blocked and by how much.
• 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 Profile Generator
• How to Create an Elevation Profile