How to distinguish low pressure trough, high pressure ridge and saddle, and what are their characteristics?

Judging high pressure ridge (line) and low pressure trough (line):

High pressure ridge (line): where the isobar bends the most, the high pressure ridge is the value from high to low (similar to the ridge in the contour map).

Low pressure trough (line): the place where the isobar bends the most, and its value points to the low pressure trough from low to high (similar to the valley in the contour map).

Judging the saddle: at the intersection of two high pressures and two low pressures in the saddle country, the air pressure value is lower than the high pressure center and higher than the low pressure center.

Low pressure trough, high pressure ridge, saddle. The narrow area extending from the low pressure area is the low pressure trough, which is similar to the valley on the contour line, and its characteristic is that the air pressure in the trough is lower than that on both sides. The connection line at the maximum bend of each isobar in the groove is the low pressure groove line, which is referred to as the groove line for short. The long and narrow area extending from the high pressure area is the high pressure ridge, which is similar to the ridge on the contour map. It is characterized in that the air pressure in the ridge is higher than that on both sides, and the connecting line at the maximum bend of each isobar in the ridge is the ridge line of high pressure, which is called ridge line for short. The middle area between two high pressures and two low pressures is a saddle-shaped pressure field, which is called saddle for short.