Blue Marble and Nighttime Lights
This dataset shows the Earth with daytime and nighttime views of the Earth, to demonstrate how only half of the Earth is illumintated at one time. The Blue Marble is an incredibly detailed, true-color depiction of the Earth, and is shown on the daylight side of the Earth in this dataset. NASA is responsible for The Blue Marble, made from a compilation of satellite images throughout 2001. Most of the information came from NASA's MODIS, the Moderate Resolution Imaging Spectroradiometer, which is attached to the Terra satellite 435 miles above Earth. The background image of the land and oceans was created using data from June through September of 2001. This could not be done in a single day or even a week because on any given day clouds are blocking a significant portion of the surface. The cloud image is a composite of three days worth of data. The first two days of data were collected in the visible wavelength and the third day was needed to get a view of the clouds over the poles using thermal infrared imagery.
The shading is true color with the oceans shades of blue, the clouds white and the lands varying from green to brown. The brown areas are the sands of the deserts. The shading of the land was done using a dataset compiled by the U.S. Geological Survey's Earth Resources Observation and Science Data Center.
On the nighttime side of the Earth, the Earth at Night data has been added. The data was recorded by the Defense Meteorological Satellite Program, DMSP, in the National Geophysical Data Center. The Earth Observation Group in the NGDC maintains the archived data, performs research on the data, and makes products utilizing the data available. The data was collected using polar orbiting satellites that provide full cover of the globe twice a day. The satellites have an Operation Linescan system which allows them to detect low levels of visible-near infrared radiance at night. The Nighttime Lights of the World data set was complied from DMSP data spanning October 1994 - March 1995. This particular visualization shows only the lights generated from electricity.
- Vastness of the Sahara Desert
- Shading done in true color: gives Earth's appearance from space
- Bright nighttime lights highlighting dense population centers, especially near fresh water and on ocean coastlines