A young woman dressed up semi-formally is reading book and drinking in the sun, seated on a bench.
A young woman reads near the ocean.
A book is used for reading, and the sun is often related to the ocean/beach.
A woman seated on a bench does not imply she is near the ocean but only that she is in the sun. This is not a logical implication.
Young woman dressed up semi-formally is a type of young woman, and is reading book is a paraphrase of reads.