Drawing the isobaric contours (curves that connect places with the same atmospheric pressure) the meteorologist defines the low (L) and high (H) barometric systems, as well as areas of smooth barometric field. Then they look for the position of fronts and examines the areas that would be affected by the fronts and low barometric systems.
These maps refer to meteorological data that are marked down on isobaric surfaces of 1000hPa, 850hPa, 700hPa, 500hPa, 300hPa, 200hPa as well as the tropopause, and maximum wind maps. In these maps, e.g. of 500hPa, after the analysis of the map with the contours of equal height of the 500hPa, the meteorologist locates low (L) and high (H) barometric systems, troughs of low pressure and ridges of high pressure, areas of strong winds and the areas of important temperature gradient.