along the southern coast
Refers to the area or route running along the southern coastline. Often used in weather forecasts, travel descriptions, or geographical contexts.
The typhoon is expected to move along the southern coast.
The road along the southern coast has very beautiful scenery.
along the southern coast
Compound of 南岸 (southern coast) + 沿い (along). The reading なんがんぞい follows standard on'yomi for the kanji.