The map in Figure 1 was created in ArcView 3.2 GIS (ESRI), with a black background to heighten contrast between land and water and also between boundaries/text and water. Both cyan and red are set off clearly by a black background. The image created in the GIS was captured as a screen shot (Alt + PrintScreen) on the Windows clipboard. Then, Adobe Photoshop 7.0 was opened and new, blank file created (Photoshop will sense the size of the image on the clipboard and choose to open, default, a new file of the size of the image on the clipboard). The image was pasted from the clipboard (Control + v ) into the new file in Photoshop.
In Photoshop, one can choose to save the image in Figure 1 for the web. If Compuserve .gif format is chosen, then the black background can be converted to "transparent." Insert the transparent .gif into a table in Netscape. The map in Figure 2 is the transparent .gif shown against the background of this page; there is no background color for the table into which the transparent .gif is inserted. Because the background is transparent, different background colors may be chosen in Netscape (in the table into which the transparent .gif was inserted as an image).
The table background may be chosen in a variety of colors suited to the needs of the case at hand. For example, choice of background color can serve as an information filter. If the red boundaries and text are to receive less visual emphasis than is the drainage pattern, choose a dark red background (red masks red; dark sets off light). The map in Figure 3 is an example of this strategy. Then again, to emphasize the red features, and reduce the visual impact of the cyan features, choose a light cyan background to partially filter the cyan. The map in Figure 4 is an example of that strategy.
Figure 1 through Figure 4 offer a sequence of static pictures of a segment of space. Figure 1 might be viewed as offering the highest contrast and it might be useful in situations where screen resolution is not good: as in the case of a screen in a classroom where delicate differences in shading are often lost in the grain of the physical screen. Some might note Moire effects, or other visual harshness, with the cyan on a gold background in Figure 2. That figure might be used as a sample of problems that can arise based on color choice. As noted previously, Figure 3 offers a scheme for emphasizing drainage and Figure 4 shows one for emphasizing text and boundaries. The map creator has the flexibility in a digital environment to create a sequence of maps and quickly change colors and other features to determine what is best suited to the case at hand.
There are matters of taste,
which are personal, and there are matters of communication, which may not
be personal. My own taste, strictly on what I "like" best, is to
prefer the subtle tones of Figure 4; however, if I wish to project the
maps for a class, then I would choose Figure 1. Further, I may wish
to back to the GIS and create more maps. Thus, Figure 5 shows topography
of the region with the transparent .gif overlain on a screen capture of
a digital map of the physical surface of the region.
The topographic surface of Figure 5 was created in ArcView 3.2 GIS (ESRI) with Spatial Analyst Extension and 3D Analyst Extension (both from ESRI) loaded on a PC. Contours, with a contour interval of 1000 feet (spacing between successive elevation contours), were loaded from the Digital Chart of the World (ESRI). In ArcView, a Triangulated Irregular Network (TIN), was created from the contours and shaded to suggest relief. This surface is created purely from the digitized points in the contours: the finer the digitizing, the finer the output.
The animated map in Figure 6 combines the high contrast map of Eastern Anatolian place names, boundaries, and drainage with a view of topography. The animation was created in Adobe ImageReady bundled with Adobe Photoshop 7.0. There are 26 layers in this animation.
In this example, animation is used to show different spatial layers separately and together (using "tweening" between separate layers) so that the eye might have the opportunity to pick up the general drainage pattern without the clutter of the TIN and then to see the TIN under the drainage pattern, using names and boundaries as visual benchmarks, in order to understand the drainage pattern. Water flows downhill; gravity pulls it there. Thus, to understand natural drainage patterns, and their spatial change over time, one must look at the underlying topographic surface. Computer cartography offers easy ways to do so.
Next steps, might involve
once again going back to the GIS and forming Virtual Reality maps from
the maps already made. The animation in Figure 6 has the temporal
spacing between successive animation frames set by the animation creator.
The reader has no control over setting the spacing. One simple way
to allow the user some control, is to save the image in a .mov format (in
Adobe ImageReady, for example) and open the .mov file in a QuickTime (Apple)
window. Added control for the reader can be offered by saving the
map, from the GIS, as a .vrml file (Virtual Reality Modeling Language file).
Then the reader can use a browser with an appropriate plug-in, Cosmo Player
or Cortona, to wander through the topography: as if he or she were
actually in Eastern Anatolia!