This is a book about techniques used in the acquisition of geographical data. The target audience is students and professionals using geographical information systems who want to go beyond the operation of the software and discover the general principles of how raw geographical data are acquired. By "raw" data we mean da ta acquired directly from the field, from photographs, or from maps but wh ich has not been edited or structured for database storage. With this in mind, we have placed a heavier emphasis on geo-referencing and data acquisition techniques, making the co ordinate reference...