Those lines are isobars. They indicate the line at which air is at that certain air pressure.
There are several different lines on a weather map. Lines with triangles leading out from them are referred to as cold fronts, while lines with semi-circles leading out from them are warm fronts. There are also lines on a weather map that are called isobars. They connect areas of equal barometric pressure.
Isobars
isobars lines of equal pressure
it is helpful to use different types of weather map because different weather map could help you, like if a map has a part that you need and the other map does not.
isotherms
air pressure
Those lines are "isobars."
the meaning of lines to stand
On a weather map, the lines that connect points with equal barometric pressure are called Isobars.Iso = equalbar = pressure
They are lines on a rainfall map showing areas of equal rainfall, similar to isobars on a weather map.
Such lines are called isotherms.
Occluded front