West Africa’s shifting nighttime coast
How do patterns of nighttime light change over time on the West African coast? Toggling the slider reveals differences between 2012 (left) and 2016 (right) that may be subtle from space but significant on the ground. Some cities have become brighter than others; increased economic activity along roads appears as glowing lines, like those that connect Ghana's coast to the interior; and clusters of fishing vessels swarm near different ports.
By analyzing high-resolution satellite images like these of nighttime light intensity, we are able to estimate economic activity and growth at the local level. This measurement is especially useful in remote, poor, and conflict-prone areas that lack reliable census, survey, and administrative data.
But since economic progress is often uneven, it’s not just the amount of nighttime light within a given area that matters. The geographical distribution of nighttime light also tells us something about how widely or narrowly the benefits of economic growth and development are being shared.
Photos by NASA’s Earth Observatory. Map by Soren Patterson for AidData.