Difference Between Digitizer & Scanner in GIS

Geographical Information System (GIS) is a computer database used to store and analyze features on the earth's surface. Both digitizers and scanners are hardware used to input information from maps and aerial photographs into a GIS.

Digitizer Hardware

• A digitizer converts point, lines and area on maps into digital data. Thumbtack in a map image by Nikolay Okhitin from Fotolia.com

  Digitizers are boards that sit on a desk or other work surface. Users wanting to digitize a map lay it flat on the board. It is important to secure the map so it doesn't move. A device much like a computer mouse is used to input points from the map. Users click on points such as road intersections or eagles' nests.

Small Scanner Hardware

• Smaller flatbed scanners look much like home office printers/multifunction machines. In fact, you can use those multifunction machines to scan maps and photos into a GIS. These are also known as video scanners.

Wide-Format Scanners

• Scanners can also be very large, standup machines. You can scan large maps and photographs into the GIS with wide-format scanners. These are more expensive than flatbed video scanners.

Data Formats

• Scanners input data into a GIS in several image formats, including: BMP, JPEG and TIFF. Digitizers create point data a GIS can use to also designate line data and area data. Line data includes rivers, roads, animal trails and hydro lines. Area data includes city blocks, animal habitats and census tracts.