Characteristics and Examples of Spatial Data - Introducing Geographic Information Systems with ArcGIS - page 143

18. You may have multiple Magnifier and Overview windows open at a particular time. Before you
experiment with these features together, save your map (like, River_Map_3), so you can get it
back if something goes wrong and ArcMap closes. What you are about to do is a sort of high-
wire act for the software. And frequent saves are a good idea anyway.
Open another Layers Overview window, resize it, and place it above the other one at the left of
the screen—obscuring the T/C. Make its Reference Layer GPS_and_Vectors. Open a Magnifier
window and plunk it into the data frame. See Figure 2-26. Spend some time looking at the
capabilities here. Zoom and pan the data frame with the usual tools. Then pan by using the
outline areas in the Layers Overview windows. Move the Magnifier window as well.
FIGURE 2-26
19. When you are through playing (and being impressed), close all magnifier and overview windows.
20. Be sure that the scroll bars are turned on. Select View > Scrollbars if they are not. You can
zoom to the full extent of all the datasets in the T/C by pressing the Full Extent icon on the
Tools toolbar. Do so now. Notice that the slider bars at the right and bottom of the data frame
are fully extended. Zoom to the extent of the DRG. Now you can shift your view of the data
frame (a different way of panning) by dragging the scroll bars. Experiment. Close all extra
windows that you have opened.
Digital Orthophotos
A digital orthophoto is an aerial photograph that has been rectified (adjusted) so that it may be used as a
map with (an almost) constant scale throughout. (Fixing aerial photos so that they become orthophotos is
a complicated process, beyond the scope of this topic. Consult remote sensing texts or the Internet if you
are interested.)