Chart projections, scale & selection
| Chart | Projection | Scale | Coverage |
|---|---|---|---|
| VNC (VFR Navigation Chart) | Lambert conformal conic | 1:500,000 | Less detail. Standard chart for VFR pilot navigation in Canada |
| VTA (VFR Terminal Area chart) | Transverse Mercator | 1:250,000 | Smaller area, more detail |
| WAC | Not stated | 1:1,000,000 | General planning of a long route. Lacks detail for effective navigation at low and medium altitudes |
Conformal:
- Angles and small-feature shapes true.
- VNC (conic): straight line is close to a great-circle track, not a rhumb line.
Scale:
- Smaller denominator = larger scale = more detail: 1:250,000 (VTA) is larger than 1:500,000 (VNC).
Grid: meridians run to true north and converge toward the pole; parallels of latitude cross them (PHAK ch.16).
Selection: route near chart edge: carry the adjoining chart too.
Trap: WAC is a long-route planning chart, not a low-level nav chart; 1:500,000 is not the larger scale; bigger denominator = smaller scale, less detail.
References
- TC AIM MAP 2.5.1
- TC AIM MAP 2.5.2
- TP 1102 Pilot Navigation (Selecting the Chart)
- TP 12880 VTA (transverse Mercator), VNC (Lambert conformal conic) objectives; VNC and VTA chart legends