A couple of years ago I blogged about the trouble one has taking politicised census figures seriously and using them to make predictions about future population growth. In that instance I was talking about Nigeria; we still rely on the 2006 census (which many dispute the accuracy of) for the population of that country and to make demographic predictions. Since the population figures are used to divide up resources between urban and rural areas and between north and south, there are widespread concerns that for decades the census figures in Nigeria have been rigged.

Now, thanks to the latest scientific research and some world famous philanthropic and computer institutions, we might be getting closer to knowing an accurate picture of Nigeria’s and other countries' population. According to Scientific American, the Bill & Melinda Gates Foundation has delivered “the most detailed and up-to-date population map ever produced for a developing country” to the Nigerian government. It is based on satellite imagery and over 2,000 neighbourhood surveys and will be used to deliver the measles vaccine next year.

The mapping project was began by the Gates Foundation after problems were encountered in distributing polio vaccines – millions of doses were sent to the wrong areas while other areas suffered shortages due to bad population data. High-resolution maps of the country’s northern states were made and the population was placed on it using computer algorithms to identify different types of neighbourhoods. This data was then used to design household-population surveys for each settlement type; the results were used to calculate population densities. The new map shows many villages that were left off the most recent census and many urban areas that are more populated than originally thought. An epidemiologist and interim deputy director of data and analytics for global development at the Gates Foundation said that the map could save US$1 billion in a few years for all vaccine types.

It is hoped that these more accurate maps can be used in other developing countries for infrastructure, health and development planning. It is expected to cost between $1 million and $2 million per country to produce these maps. The Gates Foundation is planning to expand its project to Ethiopia and the Democratic Republic of Congo. Ethiopia is to collect census data this year referenced to geographic location to capture “a true snapshot of their populations” and Nigeria will follow in 2018.

In a slightly more sinister move (or am I being too cynical?) Facebook has also joined the mapping push. This is after it announced plans in 2014 to expand Internet access worldwide using drones and satellites. It developed an algorithm to identify human-built structures and then overlaid census data. Because the algorithm is so good at finding population (especially rural populations) Facebook doesn’t need on-the-ground surveys like the Gates Foundation’s mapping project does.

So while the news is good for health and development in developing countries, and for demographers, the news is less good if you are trying to escape the Facebook newsfeed in a log cabin in the mountains somewhere. Zuckerberg will soon know exactly where you live….