Here is a picture of New Eden, the capital city of Eridani Prime:
The planet was settled soon after the advent of anti-gravity, so the capital city was built as a self-sustaining arcology utilizing the new design techniques available to house the colonists until enough other cities could be built to accommodate the massive immigration from Earth. Now that a number of centuries have gone by since first landing, many people have moved out to other cities. However, a quarter of the planet's more than 400,000,000 population still reside within the city, since many are content with the progressive living conditions in this comfortable, cultured, and beautiful city.
The city is located near the equator close to one of the few land-locked seas; the regulation of the canal system of the planet is conducted from this city through the Department of Ecology & Resources. The Technocratic Council Meets here and rules from here.