Geoscience Reference
In-Depth Information
In recent decade we watched the growing interest in visual, symbolic
aspects of multiple representations. Bedard and Bernier (2002) developed
a VUEL concept to integrate geometric, semantic, and semiotic presenta-
tion of object in multiscale environment. Cecconi et al. (2004) examine
limits of LoDs' applicability for display in various scales and accentuate
the primary role of symbolization in multiscale maps. Brewer and Butten-
field (2009) analyze data sensitivity for scale variation and propose effec-
tive combination of symbology and geometry changes.
Despite variety of existing works in multiple presentations, they have not
covered all the geographic phenomena to an equal degree in visual context.
Most of them concern discrete objects, which cartographic representation
is usually planar (2D): roads, rivers, buildings etc. The task of multiscale
mapping of relief have not been paid deserved attention.
Relief concept is used for describing earth topography. It can be logically
divided into separate forms, or treated as continuous surface. Both models
are useful in their own area and supplement each other in cartographic
relief presentation and generalization.
Manual contour drawing is made within neighboring fragments of contour
levels, which are topologically related and correspond to the same relief
form. Scale reduction and accompanying generalization process lead to
representation of higher hierarchical level of topography on the map. Con-
tour interval is increased consecutively. According to Zarutskaya (1958)
small-scale hypsometric relief representation should be geographically
credible and keeping the most distinct features of great forms which are
conditional to their structure and genesis, with respect to scale and purpose
of the map.
Careful analysis of guides and instructions for topographic mapping re-
veals that beginning from scale of 1:200 000 relief forms are extensively
exaggerated and contours are deliberately shifted and stylized to save the
morphological features typical for relief of certain genesis. Imhof (1982)
also singles out scales smaller than 1:100 000. He mentions that simplifi-
cation of lines at these scales extends more or less over the whole map
image and not only in particular places.
Scale dependency is also present in hillshading technique and hypsometric
tints selection. As Imhof states, tones and mutual contrasts of small-scale
hillshading are dependent primarily on elevations and differences in eleva-
tion, and no longer on the angle of slope. Stylized symbols for formations
gradually replace individual features (Imhof 1982).
