Swath is the width of the strip a satellite images as it passes; revisit time is how long it takes to image the same place again.
A low Earth-observation satellite does not see the whole planet at once. It paints the ground in strips as it moves, a little like a lawnmower. The width of each strip is the swath. How soon the satellite comes back over the same field is the revisit time.
NASA's Earthdata says temporal resolution depends on the orbit, the instrument and the swath width. Wider strips mean quicker returns.
Resourcesat-2's AWiFS camera covers a 740 km swath at 56 m resolution and repeats every 5 days. That is wide enough to cover India's farmland again and again through a crop season.
The sharper LISS-4 camera on Resourcesat-2A sees a narrower strip. To come back sooner, it can tilt sideways by up to 26° across track, which ISRO says gives it a five-day revisit.
Radar satellites face the same trade. NISAR images a swath of about 240 km. It covers the world's land and ice every 12 days, and because it images on both its north-going and south-going passes, NASA says the average revisit is about 6 days.
Most Earth-observation satellites use sun-synchronous orbits, which cross the equator at about the same local time on every pass. NASA's example is Terra, which crosses at about 10:30 in the morning. Pictures taken weeks apart then have similar shadows and lighting, so any change you see is real.
Watch NISAR's ground track: each orbit shifts westwards, and after 12 days the pattern repeats over the same ground. Track NISAR
Why can a 740 km swath give a five-day repeat? Work it out from the orbit.
A satellite near 700–800 km takes about 100 minutes per orbit (NASA gives 99 minutes for Aqua at 705 km). That is 1,440 / 99 ≈ 14.5 orbits per day.
While it orbits, Earth turns beneath it. After each orbit the ground track shifts west by 360° / 14.5 ≈ 24.8° of longitude. At the equator that is:
Earth's equatorial circumference = 2π × 6,378 ≈ 40,075 km shift = 40,075 / 14.5 ≈ 2,760 km between neighbouring tracks on the same day
A single 740 km swath cannot fill a 2,760 km gap in one day. The orbit is therefore designed so that the tracks on the next days fall in the gaps. The number of days needed is roughly 2,760 / 740 ≈ 3.7, so a few days, plus overlap for safety. That is consistent with AWiFS's 5-day repeat.
For a narrow swath, the same arithmetic gives a long wait. A camera with a 70 km strip needs about 2,760 / 70 ≈ 39 days to fill the gaps if it only looks straight down. Tilting changes this: by pointing ±26° sideways, LISS-4 can reach a target from several neighbouring tracks, which is how a narrow camera can still revisit in five days.
At higher latitudes the tracks crowd together (the gap shrinks with the cosine of latitude), so places in north India are revisited slightly more often than places near the equator.
Swath is the width of the strip of ground imaged on one pass; revisit time is the interval before the satellite can image the same place again.
Each pass covers more ground, so fewer passes are needed to fill the gaps between ground tracks.
It can be tilted up to 26° across track, so it can image a target from neighbouring passes, not only from directly overhead.