A ground track is the line on a map traced by the point directly beneath a satellite as it orbits and Earth turns underneath it.
Follow the sub-satellite point as the satellite moves and you draw a line across the map. That line is the ground track. It shows which parts of Earth the satellite passes straight over.
Most orbits are tilted to the equator. The tilt is called inclination. A satellite in a tilted orbit swings north of the equator, then south, then north again on every lap. On a flat world map, that up-and-down path looks like a wave.
The highest latitude the wave reaches equals the inclination. The ISS orbit is inclined at 51.6°, so its track sweeps between 51.6° N and 51.6° S.
The orbit stays fixed in space while Earth turns underneath it from west to east. So each new lap lands farther west on the map. NASA's ISS tutorial gives the shift as about 22.9° of longitude per orbit.
Because of this, the ISS does not pass over the same places on every lap. NASA notes that its tracks repeat approximately every 3 days.
ISRO gives Cartosat-3 an inclination of 97.5°. An inclination over 90° means the satellite moves slightly against Earth's spin. Its track reaches up to 180° − 97.5° = 82.5° of latitude, north and south — so it passes over almost every part of Earth.
A related idea is the sun-synchronous orbit. NASA explains that a sun-synchronous orbit crosses the equator at about the same local time each day, so images of the same place are lit the same way.
The map draws the station's ground track as a wavy line; each new loop crosses the equator about 23° farther west than the one before. Open the ISS tracker
Westward shift per orbit. The orbital plane is (nearly) fixed in space; Earth rotates at
ω_E = 360° / 23.9345 h ≈ 15.04° per hour
During one orbit of period T, the ground under the satellite moves east by ω_E × T, so the track shifts west by the same amount:
Δλ = 15.04 × T(hours)
At the equator, 22.9° is about 22.9 × 111.2 ≈ 2,550 km.
Maximum latitude. For a prograde orbit (i < 90°) the track reaches latitude i. For a retrograde orbit (i > 90°) it reaches 180° − i.
Repeat tracks. A track repeats exactly when the satellite completes a whole number of orbits N in a whole number of days D (counting the slow turning of the orbit plane). For the ISS, about 15.5 orbits a day means roughly 46–47 orbits in 3 days, which is why NASA describes an approximate 3-day repeat.
Shape. On an equirectangular map, a circular orbit's track is not a pure sine wave: the satellite's latitude follows sin φ = sin i × sin u (u = angle travelled from the equator crossing), and the longitude is stretched by Earth's rotation, so the curve leans westward.
Earth rotates eastward under the satellite's orbit, which stays nearly fixed in space, so each new orbit crosses the equator farther west.
Earth turns about 15.04° per hour; 96 minutes is 1.6 h, so the shift is about 24.1° westward.
180° − 97.5° = 82.5° north and south.