The first line of Wordsworth's poem reads, "Earth has not any thing to show more fair:". This figure of speech imagines Earth putting on a show, and not only that, putting on her best show. This display is the most "fair," or pleasant, the speaker has seen. The figure of speech is appropriate because the rest of the poem goes on to detail the wonderful natural environment Wordsworth observes.
Another figure of speech is seen a few lines later:
This City now doth, like a garment, wear
The beauty of the morning;
indicates that the city Wordsworth observes is wearing beauty "like a garment." The city is totally enveloped in the aesthetic appeal of the scene. Much of the poem is made up of vivid imagery
wherein Wordsworth describes how beautiful the city and nature look. He goes so far as to say that he has never seen such a lovely sight:
Never did sun more beautifully steep
In his first splendour, valley, rock, or hill;
Ne'er saw I, never felt, a calm so deep!
Wordsworth's exaggeration here amplifies the effect of the beautiful scene on the speaker. He is totally overcome with emotion at what he is witnessing. The scene has an emotional effect on him, calming him and giving him comfort.
Overall, the opening figure of speech is appropriate because it sets the stage for the description of beauty in the rest of the poem. Further, the dramatic details and emotional response of the speaker place this poem firmly within the Romantic poetry tradition.