I'm still not sure the difference between "portion" and "proportion". Can I replace "portion" here with "proportion"?

Native speaker’s answer
Rebecca
Not quite! A "portion" is a general part of a whole, whereas a "proportion" is a measured part of a whole, often compared to the whole. If perhaps, a specific area or part of the map were mentioned then "proportion" would work well! Ex: They gave us small portions of food at school. Ex: The head you drew is not in proportion to the body. => comparison Ex: The proportion of the map where Italy is is rather small. = The portion of the map where Italy is is rather small.