application filed February 5, 1970 was abandoned at the Supreme Court in 1977 over the issue of the patentability of computer software. Printing During the 1970s and 1980s, pen plotters, using Vector graphics, were common for creating precise drawings, especially on large format paper. However, since then almost all printers create the printed image as a raster grid, including both laser and inkjet printers. When the source information is vector, rendering specifications and software such as PostScript are used to create the raster image. Three-dimensional rasters Three-dimensional voxel raster graphics are employed in video games and are also used in medical imaging such as MRI scanners. Geographic information systems Geographic phenomena are commonly represented in a raster format in GIS. The raster grid is georeferenced, so that each pixel (commonly called a cell in GIS because the "picture" part of "pixel" is not relevant) represents a square region of geographic space. The value of each cell then represents some measurable (qualitative or quantitative) property of that region, typically conceptualized as a field. Examples of fields commonly represented in rasters include: temperature, population density, soil moisture, land cover, surface elevation, etc. Two sampling models are used do derive cell values from the field: in a lattice, the value is measured at the center point of each cell; in a grid, the value is a summary (usually a mean or mode) of the value over the entire cell. Resolution Raster graphics are resolution dependent, meaning they cannot scale up to an arbitrary resolution without loss of apparent quality. This property contrasts with the capabilities of vector graphics, which easily scale up to the quality of the device rendering them. Raster graphics deal more practically than vector graphics with photographs and photo-realistic images, while vector graphics often serve better for typesetting or for graphic design. Modern computer-monitors typically display about 72 to 130 pixels per inch (PPI), and some modern consumer printers can resolve 2400 dots per inch (DPI) or more; determining the most appropriate image resolution for a given printer-resolution can pose difficulties, since printed output may have a greater level of detail than a viewer can discern on a monitor. Typically, a resolution of 150 to 300 PPI works well for 4-color process (CMYK) printing. However, for printing technologies that perform color mixing through dithering (halftone) rather than through overprinting (virtually all home/office inkjet and laser printers), printer DPI and image