Chart Symbols and Legend
The ICAO chart is only useful if the pilot can decode the symbology reliably and quickly. Symbols and colours are standardised in ICAO Annex 4, with national conventions adding detail.
Source: ICAO Annex 4 Appendix 1 (Chart Symbols).
Topography
| Element | Depiction |
|---|---|
| Elevation | layered colour tinting: green < 500 ft, then yellow, light brown, dark brown, white above 9000 ft |
| Contour line | thin brown lines, every 100/500/1000 ft depending on scale |
| Peaks (mountains) | "+" with elevation in ft AMSL |
| Rivers | blue lines |
| Lakes, reservoirs | blue areas with name |
| Forests | green hatching (often distinguishable only by scale) |
| Cities | grey-pink areas with name |
| Railways | black lines with cross-bars |
| Motorways | red or orange solid |
| Main roads | red, medium-thick |
| High-voltage line | dashed line with "T" symbols (when above threshold) |
Aerodromes
| Symbol | Meaning |
|---|---|
| Magenta circle (ring) | uncontrolled, paved runway |
| Magenta circle with runway | uncontrolled with visible runway |
| Blue circle | controlled (tower/CTR) |
| Magenta/blue star | glider field |
| Helicopter "H" symbol | heliport |
| Cross with "U" | former or restricted aerodrome |
| ICAO code | 4 letters nearby |
| Runway length in m, elevation AMSL, frequencies | usually in aerodrome label box |
Airspaces — ICAO classification
| Symbol | Meaning |
|---|---|
| Magenta line | Class G / Class E border (in many states) |
| Blue line, hatched | CTR (control zone), Class D or C |
| Blue, hatched or dashed | TMA (terminal manoeuvring area) |
| Red hatched | restricted (R), prohibited (P) — entry forbidden / restricted |
| Blue hatched (thin) | danger area (D) |
| Grey / white | Class G, uncontrolled |
| Altitude boxes | lower / upper limit in ft AMSL or FL |
Example box:
code
TMA C
4500
↑ 2500
Means: TMA Class C, upper limit 4500 ft AMSL, lower limit 2500 ft AMSL.
Maximum Elevation Figure (MEF)
- Per chart quadrant: MEF = highest known obstacle/terrain point + 100 ft + rounded up to the nearest 100 ft.
- Given in thousand ft, hundred ft:
33= 3300 ft AMSL;109= 10,900 ft. - Pilot should maintain at least MEF + 1000 ft AGL (or higher per AIP) to safely cross the quadrant.
Source: ICAO Annex 4 Chapter 4.
Radio navigation aids
| Symbol | Meaning |
|---|---|
| Hexagonal circle with rays | VOR (with frequency, identifier, possibly DME, magnetic north marking) |
| Square with cross | NDB (with frequency, identifier) |
| Double circle | VORTAC / VOR-DME |
| Arrow with number | TACAN (military) |
| Symbol with "L" | LOM (locator outer marker) |
Visual reference points (VRP)
- Magenta arrow or red dot with name (often a 2-letter code).
- Important for approach to/departure from controlled aerodromes — pilot must identify and report the VRP ("over VRP XYZ").
Other
| Element | Depiction |
|---|---|
| Magnetic variation | dashed lines (isogonals) with value in °E/°W |
| Epoch year | in chart margin (e.g. "MAGNETIC VARIATION 2024") |
| Zone boundaries | thick black lines |
| Prohibited areas | red solid, hatched |
Learning tips
- Memorise the legend — before the first VFR cross-country.
- Walk through the chart with an instructor in the familiarisation flight.
- Mark your home area on the ICAO chart — identify landmark points for exercises (chimneys, lakes, distinctive forests).
- Pre-flight: separately note all activated airspaces along the route, all restricted areas, all NOTAM-relevant fields.