I think "itt" means "here", as in place, and "ide" is "to here", as in direction.

Like Russian "здесь" vs "сюда", or Esperanto "ĉi tie" vs "ĉi tien".

Think of it like this:

• ide -- hither (to/towards here)
• itt -- here

• innen -- hence (from here)

• oda -- thither (to/towards there)

• ott -- there
• onnan -- thence (from there)