IGMI raster maps are produced by scanning printed maps or processing the raster files (non-georeferenced) obtained at the end of the cartographic production process. Raster data, being scanned, are acquired at various DPI (Dot Per Inch) resolutions. Images are geometrically corrected (georeferencing operation) using a suitable number of ground control points (GCPs). Image’s coordinates are related to those of the corresponding point identified in the ground in order to calculate the transformation function used in the georeferencing phase. Raster cartography is georeferenced within the time zone it belongs, in the different cartographic systems used in Italy. In case of an adjacent time zone, it is also reprojected in this one. All raster maps are also available in cut out versions to help the mosaicking procedure between multiple elements. Data are provided in tiff format, 8-bit color scale, with an associated text file (tfw) with the indication of georeferencing parameters.

Raster map features are described in the table below.