Information Session: October 12, 2011 – 2:30 – 4:00 in Rm. 7-150
Interdisciplinary Field School
to Peru
June 2012
For information, contact:
Dr. Catherine Nolin (nolin@unbc.ca) or
Scott Emmons (emmons@unbc.ca)
Local interest map:
The plane crash
and death of
Prince George,
(the Queen’s
uncle) 1942
Too many lines for
black and white ?
Plane crashed on
hillside due to
inability of a
seaplane to climb
The route of the S-25 Sunderland Mk III on 25th August, 1942
Relief depiction
The representation of topography contrasts with other map elements:
….. there is a third dimension (height) that varies continuously over space
It has several components such as height, slope, shape ->->-> points, lines, areas
It can be the major visual component of the map and affects the other elements
The techniques vary in how effective they are visually and quantitatively
1. Sugar loafs
Idealized depictions from a side or oblique view;
the only form of topography on early maps (pre-1700)
Modern use of sugar loafs
.. Includes fantasy maps !
http://www.cartographersguild.com/
2. Hachures
Hachures are lines of varying width and length to depict slope steepness,
drawn in the direction of steepest slope. This was the main type of relief
depiction through the 19th century, lacking exact elevations.
In 1800 only 50 mountains heights were plotted worldwide
Hachures were systematized in
1799, where line width is
proportional to steepness.
Disadvantages of hachures
- time-consuming to produce,
obscures other information
- not very effective except in
mountainous terrain
Hachures with oblique illumination
Continuing use of hachures
Steep enbankments Mountain cliffs
http://www.richardphillips.org.uk/maps/symbols.html
http://www.gitta.info/TopoCart/en/html/ContTopo_learningObject2.html
3. Contours
Accurate surveying of elevations in Canada was developed in the 19th
century, but elevation heights became common in the 20th century.
A contour is an isarithm: line of equal elevations values
Index contours –
every 5th contour
Supplemented with
spot heights
http://ublib.buffalo.edu/libraries/asl/maps/cat/images/contours-spot.jpg
Contours
http://maps.nrcan.gc.ca/topo101/elevation_e.php
Contours are mapped from
Exploring Earth website - visualising contours stereo-photography
NTS Contour Interval: (Normal, Hilly, Steep)
1:50,000 = 10, or 20, or 40m ; 1:250,000: 50m, or 100m, or 200m
Contour interval (the distance between contour lines) depends on terrain and map scale
Index contours are symbolized as wider lines and usually every 5th contour.
Kechika 94L 1:250,000 ->
Prince George, 93G15 1:50,000
Advantages of contours
it is the most quantitative method – easy to store elevations
it is the origin for most other techniques, and is familiar to many users
Disadvantages
it is abstract (there are no lines on the ground); poorly suited to small scales
less visual, depending on: contour interval, landscape type, and experience.
These disadvantages were recognized early on and led to other methods …
1:50,000 Horseshoe Bay, BC 1:250,000 Banff, AB
4. Hypsometric Tints
The addition of colour to elevation levels, Atlas of Canada online
first tried as early as 1830.
Colour schemes require graduation,
a logical sequence, realistic colours,
and the darkest enabling readable text.
Advantages
adds visual impact, mostly at small scale; easily applied and understood
Disadvantages
exaggerated terrace effect, no new real 'information' is added,
differential contrast with other elements, and mixed color associations,
(green with forest, etc.)
which colour scheme?.. NOT the one below !
5. Shaded relief
The addition of shadows to give the illusion of depth, with a NorthWest light source (at
~45 degrees elevation). It was introduced in the C19 but more widespread after 1960
Eduard Imhof
Eduard Imhof (1895-1986) was
a professor of cartography at
the Swiss Federal Institute of
Technology Zurich 1925 - 1965.
His fame stems from his relief
shading work on school maps
and atlases.
Advantages
Highly visual, continuous in appearance (as in reality),
Can show detail and character of landscape; suitable over a variety of scales
Disadvantages
Manually - required artistic creation with pencil or air brush;
It was costly and often poorly rendered, some slopes can be very dark
Manual Hillshading examples
Combining contours and hillshading
See also this site: http://www.gitta.info/TopoCart/en/html/ContTopo_learningObject2.html
BC – aeronautical map, 1:500,000 – contours, tints, shading
Columbia Icefield, 1981 … contours, shading and rock hachures
using imported swiss cartographers
6. Tanaka illuminated contours
-pioneered in the 1950s by Kitiro Tanaka applying shading theory to contours.
-NW light source, white and black lines, variable width
Advantages
- visual and is also quantitative; and unlike shading, it did not require artistic ability
Disadvantages
Requires a non-white background; visually exaggerates terracing; poor image if not rugged terrain
Sooke, by Dolores Janzen
7. Slope zones (Nose Hill Park, Calgary)
These were not common, as they could only be interpreted from contour maps, but
show the importance of slope in determining human land use
8. 3D perspectives
Advantage: the most visual portrayal of landscape
Disadvantages: time-consuming to produce (before computers); no consistent scale
http://www.informationdesigned.com/html/maps/louise.html (Eckhard Zeidler)
‘Interesting’ local example … 3D sugar-loafs meet hobbits and skidoos
Physical Models: Challenger map (1947-54) 25 x 25 m ~1:50,000
http://www.challengermap.org
Summary of common relief depiction methods (prior to automation)
TECHNIQUE COMPONENT FEATURES
Sugar loafs shape stylistic
Hachures slope too much ink, no heights
Spot Heights elevation sporadic info
Contours elevation common but abstract
Hyps. tints elevation multiple colours
Shaded relief aspect Visual, artistic
Tanaka aspect visual but 'noisy'
Slope maps slope uniform slope areas
3D perspectives shape visual, costly, no scale
Physical models all true 3D – takes up space
Useful recap reference:
http://www.geo.hunter.cuny.edu/terrain/ter_hist.html
Next lecture:
Digital elevation models – how relief is depicted with computers