1. A method for determining a visibility range of an area, comprising: obtaining at least one digital image of at least a portion of the area; selecting a first region of interest from the at least one digital image and calculating a visibility attenuation factor based on a contrast map and a distance map of the first region of interest; selecting a second region of interest from the at least one digital image and selecting pixels in the second region of interest based on the visibility attenuation factor; and finding a pixel representing the longest distance and having a contrast around or above 5%, wherein the visibility range is determined based on the distance of the pixel.