| Related articles on the IMaGe
The University of Michigan
"The people along the sand
All turn and look one way;
They turn their backs on the land
They look at the sea all day.
They cannot look out far,
Robert Frost, Neither out far nor in deep.
Animated maps offer exciting possibilities for tracking spatial change over time. In earlier work in this journal (see links above), animated maps (or "animaps") were used to track changes, across the globe, in bee mite population over time. They were also used as analytic tools that could employ surrogate variables to mimic change over time in variables that were difficult to learn about. The introduction of time, through animation, into the mapping process allows the user to participate "with" the map in more than a purely passive manner; two examples are offered below that allow the reader some degree of interaction with the process. In the first, the reader experiences emotional involvement only and a downloadable interaction, only; in the second the reader can actually drag elements of the map around on the screen, as an instantaneous interaction achieved directly through the browser.
Thus, the "Mapplet" below offers a different perspective on the varroa mite data set. That data set shows easily that there is one country reporting the mite in 1904; in 1912 there is a siting in one other country. This sort of sporadic siting, one country at a time, occurs until 1963. Post-1963 there are multiple countries that come in on a yearly basis: sometimes 3 new additions, sometimes 7 new additions. The pattern of new receptors may show cycles; indeed, experts on the mites might reflect on whether or not the graphical pattern on number of new countries by year corresponds in any way to various biological cycles associated with the mite or its host. If it does, then choke-points in the pattern offer possible timing opportunities to intervene (Arlinghaus and Nystuen). If it does not, then one might consider the extent to which there is cyclical pattern in reporting error or in shipping (http://www.agric.wa.gov.au:7000/ento/bee.htm)and travel patterns. A glance at the maps suggests that those who live in as yet unaffected regions might find such observations of particular interest.
In the Mapplet below, the pattern of reported sitings from multiple national sources starts just after 1963: hence, the red color of 1963, as the pattern initiator. The next siting of the mites occurred in 1967, in four different countries: hence the entries of 67a, 67b, 67c, and 67d. In 1968 there were also four sitings; thus, another four boxes, 68a, 68b, 68c, 68d. The 1963 box is joined to each of 67a, 67b, 67c, and 67d using a length of line segment four times as long as the lengths from each of 67a, 67b, 67c, and 67d to each of 68a, 68b, 68c, and 68d. Variation in time between sitings is represented by varying the length of line joining them. All sitings in year X are joined to all sitings in year X+1 (or the next year in which sitings occurred). The rationale for joining all from one year to all in the next year is that one does not know how the diffusion is taking place. What is interesting here, perhaps, is that even when there are years with relatively large numbers of countries reporting sitings, still the pattern settles back to a small number eventually even though one might expect it simply to spread even more. Two obvious directions to interpret this involve reporting error or some sort of saturation of the diffusion, perhaps related to forces such as human travel patterns or mite biology, that are outside the simple mechanics of diffusion (Hagerstrand). The Mapplet can suggest directions for research questions.
Mapplet: Structural model of varroa mite diffusion through time. Pull the red year-box for 1963 all the way across to the right (use the scroll bar) and then drag and drop various pieces of the left side of the mapplet to unravel it and see the pattern of possible time points of opportunity at various stages in the diffusion process. If a box "sticks" on another, pull it in a bit of a different direction. Generally it is possible to move beyond the obstacle. Mapplets seem to offer a wide array of possibilities for description, interpretation, and analysis of complex spatial systems.