Graphical Representations

Computer Graphics
by Nic’s events

A GIS has the capability to provide good quality graphical representations, incredibly maps, creating it a possibly useful help program for the task of spatial thinking in the K-12 context. But, consumers should be aware of and know the value of information standard. Profes. sional-looking final treatments might hide information mistakes. These mistakes can be referential (i.e., an mistake in specifying anything like a street address), topological (i.e., a linkage mistake in spatial information like an unclosed polygon), relative (i.e., an mistake in the position of 2 objects relative to each other), or absolute (i.e., an mistake in the true position of anything including a floodplain boundary not aligned with property boundaries) (Tomlinson, 2003). Currently, no GIS will automatically handle information mistake hardies in a great way. Moreover, treatments can be graphically misleading.

No GIS may guide K-12 providers in the choice of chart symbols and different visual effects. The procedure of exploring information on a GI S”produced chart might be improved if consumers had real-time control over the graphic show. Many info visualization systems supply interface controls that stay “five” after the show is designed. This allows consumers to change the appear. ance of attributes in the show interactively (e.g., a color ramp, a size control for point symbols, a transparency control for an image layer). Currently, GIS shortage these a capability.

GIS offers bad help for the modeling of time (Peuquet, 2002) and associated presentations via animation (MacEachren, 1994). Unlike animation systems like Director and Flash that explicitly represent time (t) values, existing versions of GIS do not have temporal “coordinate” as in x,y,t. Although there are techniques to function around this issue, accomplished by stacking chart levels in a temporal sequence of cross sections that is refreshed many occasions per 2nd (Goodchild,. 1988), they cause a noncontinuous sense of time for consumers. Many significant aspects of research and geography revolve around processes occurring through time (e.g., carbon and water cycles, glacial change, migration, urban expansion).

Although GIS lacks the capability to look at processes that happen constantly through time, development exists for large-scale geospatial internet representations of the whole Earth over time and in 3 dimensions. Keyhole Inc. Images offers consumers, even those with legacy computers, with access to terabytes of imagery and GIS files to see Earth as a three-dimensional object. Figure 8.2 shows screenshots of Farrhviewer, which enables consumers to zoom smoothly from a whole-Earth view to resolutions because detailed because I m and to “fly” over a realistic rendering of Earth’s topography. The information to help these views are fed over the Internet, thus a broadband connection is needed foradequate performance. Farrhviewer and synonymous developments come close to the vision of”Digital Earth” outlined by past Vice President. Al Gore in Earth in the Balance (Gore, 1992). Larthviewer accommodates differing spatial resolutions, building its views dynamically from a patchwork of information obtained from different sources.

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