VISUALIZATION OF GEOCHEMICAL DATA ON MAPS AT THE GEOLOGICAL SURVEY OFFINLAND

Software for presentation of geochemical data on maps has been integra ted into a user-friendly package, ALKEMIA, at the Geological Survey of Finland (GSF). ALKEMIA contains procedures for generating dot maps, c olour surface maps, shaded relief maps, and vector images, and for int erpolating and smoothing irregularly gridded data. Combining dots and colour surfaces provides a means of visually integrating up to three v ariables on a map, revealing the spatial relationships between them. T he methods employed are described in detail, particularly the moving w eighted median, which has been widely used at the GSF for interpolatin g and smoothing geochemical and other numerical data. Several geochemi cal and oncological atlases and series of maps have been produced with these methods. (C) 1997 Elsevier Science B.V.