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Maps & Atlases

2 min read

Salvage topographic maps of your region and likely travel routes, road atlases, geological survey maps and hydrological maps, because each answers a different question: where the land rises and water runs, which roads connect towns, what rock and soil lie underfoot, and where groundwater and watersheds are. Check any map against the land before trusting it, since roads, bridges and watercourses change.

Part of Tier 1: Books That Save Lives This Week

Each kind of map answers a different question, from terrain and routes to rock, soil and groundwater.

Four Kinds Of Map, Four Questions

  • Topographic maps. USGS or an equivalent national survey. They show elevation, water features, roads, trails, structures and vegetation. Each sheet covers a limited area, so collect the sheets for your area and likely routes.
  • Road atlases. County and state level atlases show roads, towns and distances.
  • Geological survey maps. Rock types, mineral deposits, water tables and soil types. They help locate clay for pottery and construction, limestone for mortar and agriculture, iron deposits, coal and groundwater.
  • Hydrological maps. Watersheds, aquifers, well depths and water flow, essential for planning a community water supply.

Method: Choosing And Using

Step 1: Collect by area first. The sheets around where you are and where you may go.

Step 2: Prefer the larger scale for travel. Detailed topographic sheets show terrain features that an atlas does not.

Step 3: Check the date. Old maps are better than none, but verify roads, bridges and settlements on the ground.

Step 4: Orient before you rely on it. See Navigation Without Technology and Map Making.

Step 5: Protect them. Keep maps dry and out of the sun. See Book Preservation & Storage.

Common Mistakes

  • Taking only the road atlas. It shows no terrain.
  • Believing a printed bridge. Bridges, roads and dams may be gone.
  • Folding a wet map. Wet paper tears at the folds.

Safety

A map does not show what is no longer there

Collapsed bridges, flooded roads, unstable slopes and washed-out crossings are not on a printed map. Scout ahead, and do not commit to a crossing or a descent because the map shows one.

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