How was the geography of greece different from the geography of rome?

1. Greece is a scattered archipelago and a rocky mainland where communications are hardly possible. 
Rome's Italy has an unindented coast and the interior is well-connected by roads and so movement is swift. 
2. Though Roman history is not history of Italy, the geographical setting was in Italy. 'Greece' is the way the others look at its geography as an integral area, which sense of unity appears to be not shared by the Greeks themselves and displayed. Except the linguistic unity there isn't much to proclaim Greece as a nation in ancient and medieval times. 
3. Greeks were militarily not significant and have no Imperial traditions except the Macedonian race (Alexander and his dynasties). Nor were they seafarers like the Italians (Christopher Columbus was born in Genoa on Italian coast of Liguria) inspite of seamanship that didn't have any effect beyond Aegean Sea. lol I Hope this helps!! :)

Greece and Rome were peninsulas. They both had mountains as well and were both surrounded by seas on three sides. The difference is Greece had poor soil on Pelopennesus Peninsula and Rome had fertile soil on the Italian peninsula. Greece's mountains were rugged and could not trade and had to sail to trade. Rome could trade among themselves and reduced sea trade.