As part of the Integrated Resource Management System (IRMS), the Center for Agricultural Resource and Environmental Systems (CARES) is developing Internet-based data visualization of spatio-temporal information. Key concepts covered in this paper include data interpolation, automation of the map compilation process and methods of temporal data display. Animated maps can provide a unique view to users looking for trends over space and time. The Internet is proving to be the best delivery mechanism for presenting this type of information.
Integrated Resource Management System (IRMS) allows users to geographically visualize and summarize community, county, and regional information via the Internet.Internet-based visualization allows decision makers in communities to better understand their resource base – both economic and environmental – and provides a basis for making more informed decisions.As part of the IRMS project, the Center for Agricultural, Resource and Environmental Systems (CARES), is developing as part of their Internet-based socio-economic data visualization, animated time-series maps. The purpose of this paper is to examine one method of animated temporal display and to investigate the strengths and the shortcomings of animated time-series maps on the World Wide Web.
Much of the raw data for the CARES time-series animations are derived from outside sources on the World Wide Web. The data first has to be parsed out into a spreadsheet format of rows and columns. While in a spreadsheet, the data is organized to fit the specific needs of the animation. Unnecessary data is eliminated and in many cases the data is normalized by another data column. In most cases data from many files are aggregated into one file. An ArcView Avenue program was written to extract data values from the separate files and write them into a single file. In order to make the animation appear smoother, data values are interpolated for the in-between years. This file is then saved as a dBase file.
In ArcView the dBase file is joined to the appropriate spatial geography through a common identifier. An ArcView theme is created for each scene in the animation. Once the view is set, GIF or JPEG images are created for each theme in the view. Special care must be given to the orientation of each scene, for if there is a shift in even one scene, the effect of animation is ruined.
Other components of the animation need to be constructed before it is ready for web publication. A time bar is constructed for every scene in the animation. Also, if there is to be an inset map, this too must be done for every scene. One legend is usually constructed for the complete series. Again, special care must be given to the orientation of each object in the scene. It must match exactly, the orientation of every other element in every scene.
Since the advent of motion pictures we have had the capability to view a temporal map series as a continuous temporal sequence. The human brain is well suited for processing visual patterns over time, and the Internet is proving to be a valuable medium for the display of temporal information where viewing time is used to display real time. There are however a few drawbacks to the process. Probably the greatest drawback is file size. To attain the illusion of animation, many scenes must be produced. This becomes a problem not only in that it takes time to make each scene, but also in the fact that downloading times can become quite lengthy with slower Internet connections. So file size and number of scenes is a concern both in production time and in user display time. Other limitations in temporal animation will be with the data that is associated with temporal mapping. This can include changes in data collection methods, changes in the way data variables are defined and changes in the geography of the area of collection. All these factors must be closely examined before the animation process is begun.
The Internet is a new medium that will only continue to become more viable for the publishing of temporal data. Temporal map animations currently on the web are very small and simplistic due to the limitations discussed earlier. But Internet connection speeds continue to improve, and faster machines and connections will allow animations to become much more sophisticated and elaborate. Automation of the animation process will also make temporal mapping on the Internet much more feasible. Without automation, the animation process is very redundant and time consuming. And finally, temporal mapping via the Internet will become much more interactive oriented. The user will be able to select their own defined parameters such as: length of animation, point in history to begin the animation, the display speed of the animation, and possibly even which view angle or scale the animation is to be displayed.
This paper has attempted to show the great potential the Internet offers as a medium for the display of temporal information. CARES, through the IRMS project has realized the importance and viability of developing temporal web-based data visualization and data interaction. Animations may be viewed at: http://www.cares.missouri.edu/maproom/.
Center for Agricultural, Resource and Environmental Systems (CARES). An Internet-Based Integrated Resource Management System (IRMS), Second Quarter Report, Year III, 01/01/2001 – 03/31/2001. Submitted by Yan Z. Barnett and Dave Connett. College of Agriculture, Food and Natural Resources, University of Missouri-Columbia, April 15, 2001.
Geographic Information Systems Specialist
Center for Agricultural, Resource and Environmental Systems
College of Agriculture, Food and Natural Resources
University of Missouri-Columbia