Sightline

When to use it

• Will this deck see the mountain, the sea or the neighbour's new shed?
• Is there line of sight for a wireless link or a camera between two places?
• How much would a building need to rise to clear a ridge?

How to use it

1. Open Sightline and tap the observer, then the target.
2. Set the observer and target heights above ground.
3. Finish the line. The panel draws the terrain profile with the sightline over it and reports clear or blocked.

How it works

The terrain is sampled along the straight line between the two points and compared with the line joining the two eye heights, with earth curvature and refraction applied. The first place the ground rises above that line is the blocking point, and the height by which it blocks is reported.

Reading the results

Blocked by 3 m at 1.2 km means raising the observer or target by about 3 m would just clear the terrain there.

The profile shows every bump along the way, so you can see whether the block is a ridge or a small rise close to one end.

Limits and warnings

• Bare ground only. Trees and buildings along the line are not tested; use Viewshed with the surface option for that.
• 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

Related

Neighbouring tools

• Viewshed — Shows which ground within 1 to 10 km can be seen from a point, for a chosen eye height, with earth curvature and refraction allowed for and, optionally, trees and buildings blocking the view.
• Elevation Profile — Produces a cross-section of the ground along any line, with distance, total climb and descent, and gradient.