Where is the City's Center?

While living in Chicago, I had the opportunity of touring Louis Sullivan’s most important work called the Sullivan Center which is also home to Gensler’s Chicago office. The architects proudly touted how the building marked the 0,0-street grid of Chicago chosen both due to its central location and relevance to the history of the city. This led me to wonder who chooses the central coordinates of the city. In true Ayn Rand arrogance, I had subconsciously assumed that it must be an important architectural building in the city.   

Photo credit Chicago Center of Architecture

Ironically, Google spat out several links to the question “How does Google Maps establish the coordinates of a city center?” with no precise answers.  According to Chat GPT, “Google Maps typically determines the coordinates of a city center by aggregating data from various sources, including geographical databases, satellite imagery, and user-generated content. It often relies on the centroid of the city's boundary polygon or significant landmarks within the city to approximate the center point. Additionally, user engagement metrics, such as the frequency of searches and clicks within certain areas, can influence the determination of a city center”.

The answer was surprising, particularly the bit about user-generated content. I also cross referenced this response with the GIS Stack Exchange to find out that “The city center is not only and always the geocentroid but can be another place that played a key role in forming the city e.g. General Post Office. However, there are many other points of interest that could be taken into consideration as a city center, e.g. city's main square, city hall or administration, main church, railway station, port etc.”. 

For the curious, Chicago’s city center, 41.8781° N, 87.6298° W, is at the intersection of the Burnham and Root’s Monadnock Building, the Union League Club building and Mies’ Kluczynski Federal Building.

Photo credit Google Maps

Portland’s city center, 45.5152° N, 122.6784° W, is at the corner of Portland City Hall and Portland Bureau of Transportation (also referred to as the Michael’s Graves building) fronted by Terry Schrunk Plaza and Chapman Square.

Photo credit Google Maps

Click on the other coordinates to check out the places I've lived in.