Ypati is around 30 km west of Thermopylae and north of the Oiti mountains and Xerisa river , it is also 25 km west of Lamia south of the GR-38 ( Lamia - Karpenissi - Agrinio ) , around 230 km NNW of Athens and about 50 km east of Karpenissi , it overlooks the Spercheios to the north .