22.3.3 Aspens Barbara Buttenfield and Christopher Weber (1994) (9s7) developed Aspens to assist Dennis Jelinski exploring grow ng aspen trees at Waterton Lakes Nationa ark in Albe Canada. More specifically, their purpose was examine "the apparent contradiction that radial growth rates (in aspens) were higher where local enviro ental cond ons (elevation, precipitation, and soil) were more harsh" (p. 11). Although Aspens was designed solely to handle Jelinskis data, it was intended as a prototype for illustrating the broader concept of proactive graphics, a erm Buttenfield and Weber coined to describe soltware that enables users to initiate queries using icon (or sym- bolic representa is) as opposed ords Ideal argued, proactive graphics should avond steep learning curves and be "responsive commands and queries not... anticipated by system designers" (p 10). The philosophy of proactive graphics in Aspens apparent in the opening screen of the study area (Color Plate 2 where no pull down menus (which, for example, appear in MapTime) e found. Rather, it presumed that users will become information are most often availabl via the color green found on various icons example, clicking on the groen i provides information about using the displayi and clicking on the green symbol portion of the legend leads to further information Interestingly, animation begins as soon as area appears six leaves (corresponding to the six major study sites) change in size and color as each ycar of growth is highlighted in bar graph: one frame from the animation is shown Color Plate 22.2. Larger leaf and a sizes represen arget total cumulative grow darker green leaf color represents a greater tal growth for each year. Bullenfield and Weber argued having the animation start automatically is appro- priate because "The sooner graphical activity i recog e explored nized, the more quickly Prairie m A click on the name of a study s Color Plate 22.2) leads to screen of descriptive statisti and a histogram of the yearly incremental growth for th site. As we have suggested king statistical and graphi cal displays with maps is critica for exploratot analys king on a icar associated with a study site more detailed view tha up the site (Color Plate 22 3) lo distinguish th from the generalized study sile, treclike symbols rather in a man- than leaves are used The clones ner analogous to the general study site. and a histogram of yearly growth rates can also be obtained by clicking on a clone id me, it is possible to jump to another clone by clicking one of the icons in the upper right of the screen.