〜にわたって ni watatte
〜にわたって（ni watatte）means “over (a span); throughout; spanning”. Follows a noun expressing a span of time, distance, or scope to mean the action or state extends over that whole range. Formation: N + にわたって（連体は N + にわたる）
over (a span); throughout; spanning
N3Formation
N + にわたって（連体は N + にわたる）
Explanation
Follows a noun expressing a span of time, distance, or scope to mean the action or state extends over that whole range. The noun is usually large or formal (years, regions, fields). Before a noun the form is にわたる; after a verb-like main clause it is にわたって.
Examples
Note
Stresses the whole extent or duration. Compare with 〜を通して/〜を通じて, which can mean 'throughout' as well but also 'by way of'. To modify a noun, use にわたる (e.g. 長年にわたる努力).
FAQ
〜にわたって — what does it mean and how is it used?
over (a span); throughout; spanning. Follows a noun expressing a span of time, distance, or scope to mean the action or state extends over that whole range. The noun is usually large or formal (years, regions, fields). Before a noun the form is にわたる; after a verb-like main clause it is にわたって.
〜にわたって — how do you form it?
N + にわたって（連体は N + にわたる）
〜にわたって — any usage notes?
Stresses the whole extent or duration. Compare with 〜を通して/〜を通じて, which can mean 'throughout' as well but also 'by way of'. To modify a noun, use にわたる (e.g. 長年にわたる努力).