"ihan" can stand for "aivan" in spoken Finnish. The sentence decides its meaning.
"ihan" is also an ordinary written word. Check the meaning note beside each example; not every use is a shortening.
Mä asun Espoos, ihan lähellä keskustaa. - I live in Espoo, right near the centre.
ihan here: right, quite - spoken 'aivan'
Written Finnish: Minä asun Espoossa, aivan lähellä keskustaa.
Tää sauna on ihan liian kuuma. - This sauna is far too hot.
ihan here: completely, quite - spoken 'aivan'
Written Finnish: Tämä sauna on aivan liian kuuma.
Ihan hyvää, kiitos. - Pretty good, thanks.
ihan here: quite / pretty - very common softener
Ihan sama. - Whatever, I don't mind.
ihan here: quite / totally
Ei oo, se on ihan lähellä. - No, it's really close.
ihan here: quite / really
Written Finnish: Ei ole, se on aivan lähellä.
Joo, järvi on ihan vieressä. - Yeah, the lake is right next to us.
ihan here: right / quite
Written Finnish: Kyllä, järvi on aivan vieressä.
Spoken and written Finnish are different registers. The examples show how "ihan" is used here and pair it with the written sentence. Learn the meaning in context rather than replacing every occurrence of a word.