Three image types are available as GeoTIFFs for download from the version 4 composites: A number of constraints are used to select the highest quality data for entry into the composites:Įach composite set is named with the satellite and the year (F121995 is from DMSP satellite number F12 for the year 1995). The products are 30 arc second grids, spanning -180 to 180 degrees longitude and -65 to 75 degrees latitude. In cases where two satellites were collecting data - two composites were produced. The files are cloud-free composites made using all the available archived DMSP-OLS smooth resolution data for calendar years.
Version 4 DMSP-OLS Nighttime Lights Time Series With annual data stretch from 1992 to 2013, making DMSP Nighttime Light the longest data series available for nocturnal remote sensing on human activities. Since 1997, EOG had been pioneering in combining the imagery taken by DMSP-OLS to produce global Nighttime Light maps. An unanticipated consequence of the nighttime light intensification is the detection of city lights, gas flares, and fires. The PMT system was implemented for the detection of clouds at night. The VIS band signal is intensified at night using a photomultiplier tube (PMT), making it possible to detect faint VNIR emission sources.
Nighttime "VIS" bandpass straddles the VNIR portion of the spectrum (0.5 to 0.9 um). The DMSP Operational Linescan System (OLS) acquires global daytime and nighttime imagery of the Earth in two spectral bands (VIS and TIR). Air Force Defense Meteorological Satellite Program (DMSP) has operated satellite sensors capable of detecting the visible and near-infrared (VNIR)Įmissions from cities and towns.
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