Negative space is a design concept and refers to the space around and between objects ~ it is a concept that crops up mainly in art and interior design. The classic illustration is the black and white silhouette drawings.But it is an interesting idea that has many possible other uses. For example, in sports, to score a goal you have to see and aim for the negative space, that is, where the goalie is not ~ if you have played sports you will know that it is a special skill to see that space, rather than just seeing and shooting at the goalie.
When we think about humans and environment, one use of this concept might be the places humans have abandoned, spaces where once we lived, worked and played but which have failed to serve our purposes. Abandoned spaces are everywhere and there is a rich photographic record of them chronicled by hobbyists and sociologists. Much of the time they are buildings (residential or industrial) that have been abandoned, but sometimes they are simply promises of what was to come. Many years ago I spent a sabbatical in central Florida, an area dotted with planned communities that never materialized. Subdivision paved roads often with unconnected street lighting give the impression of urban crop circles.