The professionals there are certain techniques that allow to understand, what exactly is it that hides the snow-smooth surface. Striking the keys and springs are visible at any time of year, it is difficult to not notice. A stream or river, hidden under the snow, can be recognized by a relatively flat line of trees, which grow with the two sides of the channel. Also visible in the winter and reeds, denoting waterlogged territory.
Related article: KSCA auctioned 7 zemuchastkovIf growing pines, oaks, and maples that it is dry place. Spruce and birch trees can grow in a more humid soil, but this is not the swamp. Aspen and birch with a little putrefactive bark and moss on it suggests that the soil here is marshy.
Finally, many questions can be clarified not even on watching, and pre - not leaving from the house. There is always the possibility of a preliminary study of the terrain, topography, ask the presence of nearby wetlands and water bodies, nature of the soil. These cards will be found in open sources, you can gather the information in the Internet. Do they make sense in any time of the year to the viewing be armed to the teeth.