Some years ago I wrote a paper on Quarter Degree Grid Cells. Quarter Degree Grid Cells (QDGC or QDS – Quarter degree Squares) is a way of dividing the longitude latitude degree square cells into smaller squares, forming in effect a system of geocodes. Historically QDGC has been used in a many African atlases. Several African biodiversity projects uses QDGC, among which The atlas of Southern African Birds is the most prominent one.
In this posting I will present the paper and explain the general principles of the QDGC standard. Parts of the posting is from the wikipedia article describing the standard. I wrote that article so if there is any resemblance with Wikipedia there is an explanation to it. Continue reading