How to read a topographic map and navigate

Navigation is not about guessing which way is north: it is about knowing where you are on the map at all times. Contour lines, scale, and a basic compass will handle almost everything.

Scale

On a 1:25,000 map, one centimeter represents 250 meters on the ground; on a 1:50,000 map, it represents 500 meters. For hiking, 1:25,000 is the useful standard because it shows trails and terrain details.

Contour lines

• Each contour line connects points at the same elevation; the contour interval (often 10 m) is shown in the legend.
• Closely spaced lines mean a steep slope; widely spaced lines mean gentle terrain.
• Concentric closed lines indicate a summit; a “V” pointing uphill marks a ravine, while one pointing downhill marks a spur.

True north and magnetic north

A compass points to magnetic north, which does not exactly match true north on the map. That difference is magnetic declination, and it varies by location and year; on the Iberian Peninsula it is a few degrees, enough to lead you off course over long distances. Look it up for your area and apply it when plotting bearings over long distances.

Taking a bearing

1. Place the edge of the compass on the map so it connects your position and your destination.
2. Turn the rotating bezel until its lines are parallel to the map's meridians, with the N pointing toward north on the map.
3. Read the degrees at the index mark and adjust for declination.
4. With the compass in your hand, turn your body until the needle aligns with the orienting arrow, then walk in the direction of the direction-of-travel arrow, using visible landmarks to guide you.

Using your phone as a GPS: yes, but with ground rules

Your phone's GPS receiver works without cell service; downloading the map is what requires service. That is why you need to download it beforehand. Carry a power bank, turn on power-saving mode, and protect your phone from the cold, which greatly reduces battery life. And do not rely on a single device: a paper map and compass do not run out of battery.

The National Geographic Institute publishes Spain's official topographic maps, which are useful for planning hikes and printing a map of the area.