Sensor

Off-nadir angle

How far the satellite tilted from straight-down when capturing. Higher angles give more collection opportunities but degrade quality.

SATELLITE GEOMETRY · OFF-NADIR POINTINGatmosphere · topnadir25°nominal pixeltarget
Pixel elongation
1.10×
Atmospheric path
1.10×
Feature displacement
0.47× height
Quality
Good
Fig. 1 Off-nadir angle is the deviation from straight-down pointing. Drag to see the geometric consequences: pixel elongation, atmospheric path length, and feature displacement all scale with 1 / cos(angle). Above ~20° the degradation compounds; above 45° most analytics become unreliable.

Zero degrees off-nadir is pure nadir — straight down, least geometric distortion. 30° and above means the satellite was looking significantly sideways. High off-nadir means longer atmospheric path, more terrain distortion, elongated pixels, harder orthorectification, and tricky shadows.

Tradeoffs

If you care about measurement accuracy, change detection, or anything 3D, you want low off-nadir. If you just need eyes on the area, higher off-nadir is fine and cheaper because it gives the tasker more flexibility on when to capture. We generally don't recommend imagery captured above 20 degrees for analytical work.