above video describes you the concept of polyconic projection .
polyconic projection in geography is very important for making map projection.
You can also watch -
CONICAL PROJECTION
1) one standard parallel conical projection - https://youtu.be/C0XHMJL5lEc
2) conical projection with two standard parallel - https://youtu.be/asDl6VWCLXc
ZENITHAL PROJECTION
1) polar zenithal equidistant projection - https://youtu.be/WLtgKmd4820
2) polar zenithal equal area projection - https://youtu.be/lYgHDm6gLu8
3) gnomonic polar zenithal projection - https://youtu.be/VWRL4QKtUQE
CYLINDRICAL PROJECTION
1) cylindrical equal area projection - https://youtu.be/nFgjDn5wJcM
2) cylindrical equidistant projection - https://youtu.be/6t5ImZavExw
