Base station, when satellite passed it, receives signal from satellite and record it. After that you can see images on this page.
When we collect plenty of images, we need to solve the problem how to “sew it together”, to get the image of almost quarter of Earth's surface !
Because satellites move over the Earth by the different orbits and “see” the Earth at the different angles the problem cannot be solved directly, because the images even cannot be docked between each other.
For that case we use the method of orthographic projection , special projection which allow render and normalize separate images on the one plane. Orthographic or perspective azimuthal projection can be obtained by projection from the point which placed on the infinity far distance from the sphere, allows compose separate images, made at the different angles, in one picture.
The composite images which we got, using this method, you can see above.
Composite image updated by each satellite pass, of course not completely, but only the part which was “seen” by satellite.