The digital model of the terrain is represented by a DTM with a grid structure with a sampling pitch of 20 metres, which can be used both to analyze the orographic trend of the Lombardy territory and to carry out various types of studies, being integrated with the other vector databases of the regional territorial information system. The coverage includes the hilly and mountainous areas of the Lombardy Region. The GRID is a raster file developed by Esri, which has two formats: A proprietary binary format, also known as ARC / INFO GRID, ARC GRID and many other variants, and an ASCII format non-proprietary, also known as GRID ASCII ARC / INFO. The binary format is widely used in Esri programs, such as ArcGIS, while the ASCII format is used as an exchange, or export format, due to its simple and portable structure. The GRID represents geographic space as a matrix of equal-sized square grid points composed of rows and columns. Each grid point stores a numerical value that represents a geographic attribute (such as surface elevation or slope). Each cell of the grid is georeferenced.
