The warning comes from the Swedish authority for mapping, cadastral and land registration, Lantmäteriet, which produces the official maps.
And the digital property map does give an impression of being exact, with clear coordinates and razor sharp lines, showing buildings, different ground types, roads and property boundaries.
But the detail is deceptive, says Susanna Collin, head of the national mapping agency Lantmäteriet in Visby on the island of Gotland, of the Swedish east coast.
"Well, what happens is that people erect houses on the wrong spot. Sometimes it does not matter that much, but sometimes it matters more, when the plot is narrow, and it is close between the buildings," she says.
Other examples are when people have decided to chop down some trees, only to discover that it in fact was trees that belonged to the neighbour.
"Oh, yes, that has happened of course. At other times people get a shock when they think that a plot boundary goes straight through their house. But when we look at it, we realise something has is wrong, and normally it is the map that has shifted a bit," she says.
So it may be good to know that the plot boundaries on the digital map are not always correct, and they are not legally binding. According to Lantmäteriet the margin of error varies from a few centimetres to an average of some ten metres. The worst examples Susanna Collin has seen are from Fårö, a smaller island north of Gotland. There the discrepancy is about 40 metres between the map and reality.
But that is the extreme, says Susanna Collin, and notes that the digital maps are constantly complemented and updated. But there is still room for improvement.
"You should be a bit careful how you use it," she says "and always check the digital map against the original maps at the land registry - and if you are still unsure, you should check the markings that are out on the plot itself, because they are the ones that are referred to in the law."