What Does Grid System Mean?

A Grid System or a Grid Coordinate system is basically a system, that is mathematically adjusted to, a map projection so that the geographic positions or the latitudes and longitudes may be readily transformed into plane coordinates. All the computations related to them are made by ordinary method of plane surveying.

It allows the location of a point on the map to be explained in a meaningful.  way. The earth's surface is projected in a way that it allows representation of an area on a flat pier of paper.