The Fire History GIS layer represents fire ignition locations as points and fire perimeters as polygons. At Sequoia and Kings Canyon National Parks, fire history information is compiled from various sources including fire reports, drawn maps, remote sensing, and GPS. Some perimeter data prior to 1996 originated as GRASS coverages with 30 meter resolution. Beginning in 1996, spatial data was digitally developed in ArcGIS at varying scales (typically digitized from 15 minute or 7.5 minute topo quads). Spatial and attribute accuracy are greatly increased from year 2002 and later.