Esri grid
An Esri grid is a raster GIS file format developed by Esri, which has two formats: 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. The grid defines geographic space as an array of equally sized square grid points arranged in rows and columns. Each grid point stores a numeric value that represents a geographic attribute (such as elevation or surface slope) for that unit of space . Each grid cell is referenced by its x,y coordinate location. File formats. ASCII. In Esri grid data, the first six lines indicate the reference of the grid, followed by the values listed in "English reading order" (left-right and top-down). For example, consider a grid, shown to the left. This could be encoded into an ASCII grid file, that would look like: where The remainder of the file lists the raster values for each cell, starting at the upper-left corner. These real numbers (with optional decimal point, if needed) are delimited using a single space character. Binary  format. A binary Esri grid is stored in several files contained in at least two directories: the "name" directory and an "info" directory, where "name" has strict naming conventions. The grid name must begin with an alphabetic character and must only include alphanumeric characters or the underscore ("_") character. A multiple-band grid (a collection of grids also known as a "stack" in ArcGIS) cannot have more than 9 characters in its file name, and a single-band raster dataset cannot have more than 13 characters.