Beyond citing Lynch's five structural elements, Passini gives three conceptual aspects of spatial imageability that he finds to be even more important in wayfinding. These are a structure's spatial organization, spatial enclosure, and spatial correspondence.
Spatial organization is the scheme upon which the structure is organized. If navigators can correctly discern this scheme, they can predict features of the structure. In a hypertext, this corresponds to the scheme by which the connections are (or are not) constructed between lexia.
Spatial enclosure is how a structure's external features give clues to its internal layout. For example, when a building has a rectangular perimeter, people assume that the internal circulation is also rectangular. Without edges, this is difficult to convey in hypertext. But an overview of the site's structure and a strong "district" atmosphere can help convey enclosure.
Spatial correspondence is how separate areas and landmarks lie in relation to one another. With paths of zero length, this has no physical meaning in hypertext. But instead of physical correspondence, we can talk about conceptual correspondence. Understanding the organization scheme helps us predict where things should be. But in order to navigate to this intended destination, we need to determine where we are within this scheme. Thus, each lexia should provide orientating information about where it lies (or how it "corresponds" to) the organizing scheme.
The organization of These Waves is relatively clear after some study, especially when the URLs and filenames are considered. The work is organized into a number of story threads. Threads are grouped into eight subsites, each with an associated navigation frame. These eight subsites are all accessible from the first menu4 page.
As a building's outer enclosure gives clues to its internal layout, a site's main navigation page should give clues to its structure. Though the menu4 page tries to give this overview, and each subsite frameset tries to catalog its child threads, it is possible to wander onto a different subsite's thread without leaving the current subsite's outer frame. When this happens, the subsite's enclosing edges and distinction are undercut by the ability to surf to any thread within its frame.
Determining spatial correspondence involves determining where we are currently located in relation to the surrounding structure. As mentioned, the weak use of landmarks makes selecting a direction difficult. Ambiguously identified and poorly enclosed districts and threads make establishing the current location more difficult. Though eventually the reader can recognize threads by their story content, and can sometimes be guided by small back and forward arrows, it is easy to wander to the middle of another undifferentiated thread through various links.
Cover → Introduction → Structure → Connections → Imageability → Navigation → Conclusion → Works Cited