What do the lines on a weather map that join areas of equal pressure represent?

The lines on a weather map that join areas of equal pressure are known as isobars. They help in visualizing the distribution of atmospheric pressure over a particular area, providing valuable information for weather forecasting and understanding wind patterns. When isobars are closely spaced, it indicates a steep pressure gradient, which often results in stronger winds. Conversely, widely spaced isobars signify a gentle pressure gradient and typically lighter winds. Understanding isobars and their implications is essential for pilots, as they aid in predicting weather changes that can significantly affect flight safety and operations.

The other terms do not represent lines of equal pressure: isotherms relate to temperature, isoclines deal with magnetic declination, and isohyps are used in topography to represent lines of constant elevation above sea level, making them unrelated to atmospheric pressure readings on weather maps.