In demographics, the center of population (or population center) of a region is a geographical point that describes a centerpoint of the region's population. There are several different ways of defining such a "center point", leading to different geographical locations; these are often confused.

Three commonly used (but different) center points are:

A further complication is caused by the curved shape of the Earth. Different center points are obtained depending on whether the center is computed in three-dimensional space, or restricted to the curved surface, or computed using a flat map projection.

The mean center, or centroid, is the point on which a rigid, weightless map would balance perfectly, if the population members are represented as points of equal mass.

Mathematically, the centroid is the point to which the population has the smallest possible sum of squared distances. It is easily found by taking the arithmetic mean of each coordinate. If defined in the three-dimensional space, the centroid of points on the Earth's surface is actually inside the Earth. This point could then be projected back to the surface. Alternatively, one could define the centroid directly on a flat map projection; this is, for example, the definition that the US Census Bureau uses.

Alan H. Weisman (born March 24, 1947 in Minneapolis) is an American author, professor, and journalist.

Weisman holds both a bachelor's and master's degree in literature from Northwestern University. He is Laureate Professor in Journalism and Latin American Studies at the University of Arizona, where he leads an annual field program in international field journalism. He has also taught writing and journalism at Prescott College and Williams College and has been a Fulbright Scholar in Colombia.

He has written several books and won numerous international awards for his work in journalism and literature, the most recent being the critically acclaimed The World Without Us, which describes a post-human scenario of the planet. Among his other works are Gaviotas: A Village to Reinvent the World (1998), winner of the Social Inventions Award from the Global Ideas Bank, An Echo In My Blood (1999), La Frontera: The United States Border With Mexico, and We, Immortals (1979). His reports on Latin America have appeared in Harper's, The New York Times Magazine, the Los Angeles Times magazine, the Atlantic Monthly, Orion, Audubon, Mother Jones, Discover, Condé Nast Traveler, Resurgence, and several anthologies, including The Best American Science Writing 2006.

Well known for her leadership in international non-government organizations (NGOs), Musimbi Kanyoro is passionate advocate and popular speaker for the promotion of health, sustainable development and human rights, with a special focus on women, children and minority groups. She is currently the President and CEO of the Global Fund for Women and has served on many social justice and international development boards. Dr. Kanyoro has written and published extensively in these areas. In 2005, Dr. Kanyoro was one of the nominees for 1000 Women for the Nobel Peace Prize.

Musimbi Kanyoro (née Angogo) was born 30 November, 1953 the fourth daughter of Dina Nyagoha and Thomas Angogo in South Nyanza Kenya. She attended the Alliance Girls High School and the University of Nairobi for her undergraduate work and did her Masters and PhD at the University of Texas in Austin. Musimbi was a visiting scholar in Hebrew and the Old Testament studies at Harvard Divinity School and obtained a Doctor of Ministry in Feminist Theology at the San Francisco Theological Seminary. Musimbi began her involvement with the global agenda of the United Nations at the Third World Conference on Women in Nairobi, 1985 where she played a leading role on the national host committee. Moving to Geneva, Switzerland in 1988, she then went on to play a key role in the preparation for and execution of the NGO participation in the five major United Nations conferences of the 1990's: Conference on Environment and Development (UNCED) Earth Summit, Rio de Janeiro, 1992, World Conference on Human Rights, Vienna, 1993, International Conference on Population and Development (ICPD), Cairo, 1994, Commission for Social Development World Summit for Social Development, Copenhagen, 1995, Fourth World Conference on Women, Beijing, 1995.