Topographic maps: the mountain standard
These are the ones with contour lines, the lines joining points at the same altitude. With a little practice they tell you at a glance where the pass is, whether a climb is gradual or a wall, and which way water would run. For planning in mountain terrain they are irreplaceable.
IGN Topo
The official map of Spain's Instituto Geográfico Nacional, equivalent to the printed MTN series. For Spain it is the best reference available: rigorous place names, waymarked trails, shelters, springs and protected-area boundaries. Its one weakness is that it updates slowly: a new forest track can take years to appear.
OpenTopoMap
A topographic map built on OpenStreetMap data, with worldwide coverage. Outside Spain it is one of the best free options, and inside it has one clear advantage over IGN: being collaborative, it reflects changes on the ground sooner. In exchange, its quality depends heavily on how many people have mapped that area.
World Topo Map
Esri's topographic map. Consistent, very readable and with solid global coverage. It works well as a second opinion when IGN and OpenTopoMap disagree.
Switch between all nine base maps over your own route and compare.
Open the GEPYX editorSatellite: what is actually there
Aerial imagery does not interpret the terrain, it shows it. It is the definitive tool for the question no map answers: does that dotted-line trail still exist?
IGN Satellite (PNOA)
Spain's official orthophoto, at excellent resolution. You can make out trails, stone walls, scree fields, even whether a meadow has been mown. For checking access roads and parking it is the best there is.
ESRI Satellite
Worldwide coverage at good resolution across most of the planet. It is the natural complement once you leave Spain.
Satellite imagery has two limits: you see nothing under the forest canopy, and a summer image tells you nothing about the winter state of the same terrain.
Vector maps: Bright, Liberty and Positron
These are street maps: fast and razor-sharp at any zoom. They have no contour lines, so they are no use for reading relief, but they are unbeatable for logistics — getting to the village, finding the car park, reading a street name.
Positron deserves a special mention: it is nearly grey, with very little contrast, and precisely because of that it is the best background when what you want to see clearly is your track, without the map competing with it.
CyclOSM, for tracks and surfaces
Designed for cycling, it highlights surface type with its own colour code: tarmac, dirt track, path. Even on foot it is very useful for telling at a glance whether a section is a wide track or a narrow trail.
The strategy that works
Do not pick one map: use three and compare. The tried-and-tested method is this:
- Topographic to design the itinerary and understand the relief.
- Satellite to verify the doubtful sections and the access.
- Vector or CyclOSM for logistics and surface type.
In GEPYX you have all nine maps and can switch between them without losing your track, with hillshading available on top. When two maps disagree about something, that is usually exactly the spot worth looking at twice before you set off.