There are many interpretations of this work, and unfortunately the author was alive long enough to write much about it and react to some of those interpretations.
It is my personal opinion that an artist is not a critic, and should not try to be, they should sit back and not try to explain their work. Because their words have a huge impact on how people enjoy it. And usually only hurts people's enjoyment and interpretation.
Therefore, I will not write any of what he has said about it, but I will say it is available if you want to ignore the joy of building your own interpretation. I will say it is simply a beautiful painting, painted with hints of impressionism, expressionism, even possibly cubism. This work is way ahead of its time, and was considered by some at the time to be the most beautiful American painting ever.