Layout Design
map product. For example, the Lambert Conformal Conic projection would inform
a knowledgeable viewer that the map is great for discerning the real‑world shape of
mapped features but that using it for measuring the area of those features may yield
erroneous results. However, if the viewer is not knowledgeable about projections,
the same information could be described on the map in a more direct way by simply
stating
the limitations of the map (e.g., “Not for use as an area measuring tool”).
Best Practices
If your map audience is comprised of geographers or cartographers and possibly
GISers, the projection information will be appreciated, depending on the subject
of the map. However, even if the audience is comprised of only GIS professionals,
you may still want to consider laying out clearly what the projection consequences
are as not all GIS professionals are up to speed on projection nuances. By including
both forms of text, the projection and its limitations, you can ensure that everyone is
adequately informed.
Placement
The map projection information is placed in the margin along with the other metadata
elements that are similar such as the disclaimer, data sources, data citations,
and copyright.
Inset Map
An inset map is a small map relative to the primary map, generally with a ratio
of about one eighth to one sixteenth the size of the primary map element. The
inset map has two potential functions. One is to show an area of the primary map
in more detail by zooming in to a portion of the primary map and the other is to
give an overview of the primary map’s location by zooming out from the primary
map. This latter type of inset is variously referred to as an “inset,” “overview,”
or “locator map.” An example of the zoomed‑in type would be large‑scale maps
of particularly densely populated portions of a county in order to allow all of the
mapped features to be viewed adequately.
An example of the zoomed‑out type
would be a watershed map that shows a stream in relation to the mainstem and
other tributaries,
shown in conjunction with a main map showing just the stream
and detailed stream survey attributes.
Best Practices
The same features and feature styles in the primary map element need to be duplicated
in the inset map element. The orientation, or north position, should also be the
same as in the primary map. Additionally, it is usually necessary to highlight the
position of the inset’s features on the primary map using a box, shaded area, or other
such technique if it is of the zoomed‑in variety. Lines coming out from the primary
map’s box and connecting with the inset map, sometimes called “rays,” visually connect
the inset with the corresponding inset box on the main map (see Figure 3.20).