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Read a specific slope from topographic contours
Contour lines encode slope steepness, direction, and specific landforms if you know how to read them.
Topic summary
Contour lines encode slope steepness, direction, and specific landforms if you know how to read them.
Intended uses
Navigation skill (all levels, ~10 min practice)
Step-by-step
Check the map's contour interval (usually 20, 40, or 100 feet) — every line represents that much elevation change.
Close-packed lines mean steep terrain; widely spaced lines mean gentle terrain.
V-shapes pointing uphill are drainages and streams; V-shapes pointing downhill are ridges.
Concentric closed loops mean summits; loops with tick marks pointing inward mean depressions or basins.
Estimate slope steepness: contours a millimeter apart on a 1:24,000 map with 40-foot intervals mean roughly a 45° slope — near the limit of walkable.
Tip: Trace a proposed route with your finger and count contour crossings — every crossing is one contour interval of climb or descent.
Related outdoor skills
Educational reference only. Wilderness conditions change fast — practice in low-stakes settings, take a certified wilderness first-aid course, and confirm regional regulations before you rely on any of these skills in the field.