An Esri grid is a raster GIS file format developed by Esri, which has two formats: 1. * A proprietary binary format, also known as an ARC/INFO GRID, ARC GRID and many other variations 2. * A non-proprietary ASCII format, also known as an ARC/INFO ASCII GRID The formats were introduced for ARC/INFO. The binary format is widely used within Esri programs, such as ArcGIS, while the ASCII format is used as an exchange, or export format, due to the simple and portable ASCII file structure.