essential
likely
maybe
probably not
Front (prompt)
Across-track vs along-track scanners — examples?
Plain English (default view) — short, conversational, lightly seasoned with science
🔬 Scientific / formula (revealed on click) — markdown + $$…$$ ok
Two scanning geometries used by multispectral sensors: - 🔄 **Across-track (whiskbroom)** - How: discrete detectors + scanning mirror sweeps perpendicular to flight - Examples: Landsat MSS, TM, ETM+ - Drawback: moving mirror = mechanical wear - ➡️ **Along-track (pushbroom)** - How: linear array of detectors — no moving parts - Examples: SPOT HRV, IRS LISS, IKONOS, QuickBird, Landsat 8/9 OLI - Wins on: longer dwell time → better SNR, more reliable
💡 Mnemonic / memory aid (shown on hover)
Whiskbroom WIGGLES a mirror (Landsat 1–7). Pushbroom PUSHES a linear array straight ahead (SPOT, IKONOS, Landsat 8/9 OLI). No wiggle, no breaking part.
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