Having identified some interesting information, users often want to link it with some information from a different source and/or in a different form. An example here would be the combining of information on mineral deposits from a Geographical Information System (GIS) with administrative areas such as boundaries or coded data such as postcodes. There is an enduring problem for the user of linking information in a digital form with both hard copy and the less tangible 'intelligence'. It may be that multimedia databases will offer some solutions here, providing flexible access to different forms of information. However, as mentioned earlier, the
problems of indexing complex media such as graphics, sound and video based on the content of the objects are immense.