These highly detailed maps show all the administrative boundaries, settlements as small as isolated farms, the road network down to unfenced roads and country tracks, and field boundaries (hedges and drystone walls) which make navigation across the countryside much easier. Steep gradients on roads are indicated. Various landmarks, e.g. powerlines, archaeological sites, windmills, churches and lighthouses are shown and additional graphics indicate natural terrain features such as cliffs, scree, mud and vegetation variations. The contour interval is 5 metres in the lower parts of the country and 10 metres in the uplands, and spot heights are marked. Each map covers an area of 30 x 20km (i.e. approx. 19 x 12 miles), with some double-sided maps covering more, as indicated in the individual descriptions. The maps are fully GPS compatible, with the National Grid shown at 1km intervals and latitude and longitude indicated by margin ticks at 1'.