Map Layer Information: Previous MODIS

This layer contains all Thermal MODIS data that were submitted to GeoMAC within the previous thirty days.

This layer displays information on fire locations from Moderate Resolution Imaging Spectroradiometer (MODIS) fire detection data.  MODIS fire detection data for the current year are compiled Terra and Aqua MODIS fire and thermal anomalies data. The MODIS instrument images the entire surface of the Earth every two days (daily in northern latitudes), making observations in 36 co-registered spectral bands at moderate spatial resolutions (250, 500, and 1000 meters). Thermal information is collected at 1000-meter spatial resolution. The collected thermal information is converted to ellipse-shaped vector polygons. These collections are processed through the MODLand Rapid Response System using the algorithm described by the MOD14 Users Guide. The thermal MODIS data is shown by the color of the symbol on the map. This thermal data is collected twice a day, at 2:00 PM EST and again at 12:00 AM EST and are then processed and merged into a single map, which is available by 3:00 AM EST.

The currency of the thermal MODIS data is shown by the color of the symbol on the map.

Map Legend

Thermal MODIS Map Legend

The Thermal MODIS layer is generally updated daily, as the data are made available to us.  However, there may be gaps in daily coverage as explained below.  If we have received no new data, the "expired" layers are not replaced.  The layer is replaced as soon as we receive an updated file.

GeoMAC only displays data as they are submitted by field offices.  Since data are not received for all fires, you may not be able to view every fire.  Once a data file is more than 24 hours old, or is replaced by a more current file, it is displayed in gray in the Past 2010 MODIS layer.  Also, data are usually no longer collected once a fire is no longer growing in size and is mostly contained.

These maps of fire locations are compiled by the USDA Forest Service Remote Sensing Applications Center in cooperation with NASA Goddard Space Flight Center, the University of Maryland, and the National Interagency Fire Center. The thermal information is collected at a 1 km spatial resolution and converted to ellipse-shaped vector polygons. The geolocation of the centroid of each polygon is within one-half of one pixel (500-meters) of the location shown on the map.

These two collections are processed by the MODLand Rapid Response system and merged into a single file.