For years England has laughed over German theoretical discussions of how best to invade England, and German studies of English coast lines and country resources.
I heard years ago of a young Englishman who disputed in Berlin the war-office plans of his father's estate.

He declared that he thought he ought to know the land where he was born and brought up as a boy, and that there were only two springs of water thereon, instead of three.

The German general staff said their maps of England were correct and were not based on English authority.

The young man found on his return to England that the German maps were correct and that his father's estate had three springs whence men and horses could be watered, although his family had never noted the existence of a third.
Two years ago some friends of mine were playing tennis in an English village and inquired the occupation of two young Germans, who seemed to be good tennis-players, but without family relations or settled business.
The response of the hostess was: "Oh, they are just two German spies of good education and charming manner looking over the country here, and we find them very useful in making up our tennis tournaments." It was looked upon as just a part of the German map-making plans, and England was an open book for anybody to map.

Baedeker published the guide-books of the world: why should n't the Germans make all the maps of the world,--especially if German map-making were cheaper than English map-making?
A banker friend of mine found two young Germans in his village, with no other occupation than motoring the country over and making notes and sketches of cross-roads, railroad junction-points, important buildings, bridges, etc.