Contour lines are the language of terrain. A New Zealand contour map translates a three-dimensional landscape — peaks, valleys, ridges, and plains — into two dimensions on a printed or digital surface. For trampers, planners, geologists, and anyone working outdoors, reading contour lines accurately is a foundational skill.
How Contour Lines Work
A contour line connects all points at the same elevation. If you were to walk along a contour line, you would neither climb nor descend — you would stay at exactly the same height above sea level. The vertical distance between adjacent contour lines is called the contour interval, and it is consistent across each map.
On New Zealand’s standard Topo50 maps, the contour interval is 20 metres in most areas, with 10-metre intervals used in lower-lying terrain to capture subtle relief. Every fifth contour is an index contour — drawn thicker and labelled with its elevation — making it easy to count up or down from a known height.
Reading Terrain from Contour Lines
Several terrain features are immediately recognisable in contour form:
- Ridges and spurs: Contours form V or U shapes that point downhill (away from higher ground).
- Valleys and stream channels: Contours form V or U shapes that point uphill (toward higher ground). Streams nearly always flow in these V-pointing-uphill gaps.
- Summits: Concentric closed loops, with the innermost loop at the highest point.
- Cliffs and bluffs: Contour lines so close together they appear to merge — sometimes shown with special cliff symbols on NZ topo maps.
- Saddles and passes: An hourglass shape where two sets of concentric contours narrow toward each other. Most tramping passes cross at saddles.
- Plateaus: Wide spacing with very few contour lines across a large area.
Contour Intervals and What They Mean for Tramping
Choosing the right contour interval matters depending on the terrain and your purpose. For route-finding in steep alpine terrain, a tight interval (5-10 m) reveals gullies and rock bands that a 20-metre map would obscure. For planning a long-distance tramp across rolling hill country, 20 metres is enough to show the shape of the land without cluttering the map.
The NZ Elevation Tools contour map generator supports intervals from 0.5 m to 50 m, so you can tailor the detail to your need. Draw a rectangle around any area of New Zealand — a specific valley, a track section, or a mountain range — and it generates contour lines directly from LINZ LiDAR data.
New Zealand Terrain Features in Contour Form
New Zealand’s geology produces terrain types that are particularly recognisable on contour maps:
- Volcanic craters: Near-perfect concentric circles, often with a slight depression at the summit shown as a closed contour with tick marks pointing inward.
- Glacial cirques: A steep-walled, bowl-shaped depression at the head of a valley — tightly packed contours on three sides opening to a valley below.
- Canterbury braided rivers: Flat, wide floodplains show up as large gaps between contours, with river channels barely changing elevation across hundreds of metres of width.
- Fiordland walls: Near-vertical contour lines in some of New Zealand’s most dramatic terrain, with fiords cutting thousands of metres from ridgeline to sea level within a few kilometres.
Using Contour Maps for Tramping Safety
Contour maps underpin all backcountry navigation in New Zealand. Before any tramp, read the contour map to identify where the track crosses open ridges (exposure to weather), where it descends into valley floors (river crossing risk), and where bluffs might block an off-track escape route.
For an overview of the major elevation zones across the country, see the New Zealand elevation map guide. For the full context of everything else a topographic map shows beyond contour lines, see the guide to New Zealand topographic maps. If you are planning a specific Great Walk and want elevation profiles rather than just contours, the New Zealand hiking and tramping maps guide has those covered.
