What marking indicates Class E airspace beginning at 700 feet AGL?

Class E airspace that begins at 700 feet Above Ground Level (AGL) is depicted on aeronautical charts with a dashed magenta circle. This marking indicates that the airspace is controlled and extends upwards to higher altitudes, starting at the 700 feet AGL level.

The use of a dashed magenta circle visually signals to pilots that they will enter Class E airspace at this specific altitude when transitioning from uncontrolled airspace. This delineation is essential for pilots to understand the type of airspace they are navigating through, as it helps them adhere to the appropriate flight rules and ensure safety during their operations.

The other markings mentioned refer to different classifications of airspace. Solid blue circles represent Class B airspace, solid magenta lines suggest the boundaries of Class D airspace, and notched circles indicate Class C airspace. Each of these is distinctly relevant within the NAS but serves to denote different types of controlled airspace with specific operational requirements.