Geoscience Reference
In-Depth Information
2.4.3 Hypsometric tints
Hypsometric scale should be developed for every map scale of the defined
series. Consecutive scales of multiscale map will be coherent if tint colors
are similar and successive without sudden tone changes. The more scale
increases the more difficult is the task of creating distinctive layers of
color. Imhof (1982) argues that number of colors should not exceed 6-10,
otherwise they will be hard to distinguish. Therefore in large scales, where
contour interval is small but terrain forms are relatively large in size, a
transition from layered to gradient color shading would be effective.
2.4.5 Hillshading
Hillshading of already generalized DEM is rather simple using standard
GIS instruments. We also recommend combining oblique and vertical hill-
shading in any scales, as this kind of shading reveals ridges and valley
bottoms clearly. In smaller scales there usually more need in exaggeration
of DEM to give hillshading more contrast (up to 10 times). In large and
middle scales exaggeration factor can usually be set to 1-5 when combining
with hypsometric tints and contours.
3- Results
The proposed methodology was applied in preparation of multiscale hyp-
sometric map of the European part of Russia. Esri ArcGIS Desktop 10
software was used as it allows implementing of all stages of proposed
methodology. The scale range of the map extends from 1:25 000 to
1:50 000 000 and the series includes 11 scales differing in 2-2.5 times
from each other. Data sources used in this project include public Russian
topographic maps of scales 1:25 000—1:1 000 000, and free digital eleva-
tion models ASTER GDEM and USGS GTOPO30. In large and middle
scale the coverage of the map is fragmented, which is caused by availabil-
ity of suitable source data. The scale of 1:25 000 is available on the Black
sea coast of the Northern Caucasus, and the largest scale for Central
Russian Upland is 1:200 000.
