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Graphical Notice to Air Missions (NOTAMs) may appear as circles instead of detailed polygons or airspace shapes. This article explains why this occurs and how graphical NOTAM geometry is generated.

Overview

Graphical NOTAMs are created using location and geometry data included in the International Civil Aviation Organization (ICAO) NOTAM message. In some cases, the system can automatically generate a detailed shape from the NOTAM text or associate the NOTAM with a known airspace. When this is not possible, the NOTAM is displayed as a circle.

How Graphical Shapes Are Generated

The system prioritizes geometry data contained in the NOTAM Q-line. The Q-line commonly includes:

• A center coordinate.
• A radius defining the affected area.

When only coordinate and radius information are available, the graphical NOTAM is displayed as a circular area.

If additional information is available and can be reliably interpreted, the system attempts to generate a more accurate graphical shape by parsing the NOTAM text for boundary coordinates or shape definitions.

Why Some NOTAMs Default to Circles

A NOTAM may display as a circle for several reasons:

• The ICAO NOTAM only provides a coordinate and radius in the Q-line.
• The NOTAM text does not contain sufficient information to construct a polygon.
• The NOTAM text format cannot be automatically parsed.
• The referenced airspace cannot be confidently identified.

In these situations, the circular depiction represents the best available graphical interpretation of the NOTAM.

Manual Shape Corrections

When possible, graphical NOTAM shapes may be reviewed and corrected manually to improve map accuracy. However, manual corrections depend on the clarity and completeness of the source NOTAM information.