This shows the list of participants for the DebConf25 Key Signing Party. Its utility is to find whom are you better connected to, and with whom should you ask for signatures.
Do note that the SHA256 of the file *I* used to generate this file is:
E321 CE1D A781 DF71 1698 24D8 D526 43AC A1D1 16F8 9075 1A2C EB34 3C92 C5B1 8EF9
Of course, you don't want to be carrying that many pages with you at all times. You can download a convenient PDF with only the basic information — but make sure to validate the full document, and refer to it (check all of the fingerprints you are signing do match) when actually signing.
There are really no guidelines to this. But...
There is no need to be at the geographic center, only to introduce as much redundancy (in the good sense) as possible.