THIS WEEK
Ma p Design
Today in Geo gr aphy 423:
TOPOG RAPHY AND TERRAIN
• Representing Topo/Terrain I:
• Lecture: Mapping Terrain
• Lab: Campus Map
• Final Projects
Introduct io n to Topo gra phic
Ma pping
• READ HANDOUT
– Intro and Background
– Traditional approaches
Geography 423
November 18, 2008
Definit io ns
• Topography: the arrangement of
natural and artificial features on the
ground
Definit io ns
• Topography: the arrangement of
natural and artificial features on the
ground
• Terrain: a stretch of land, esp. in
regard to its physical features
TOPOG RAPHIC DATA
• Topographic data includes:
– Elevation data
• Height above (or below) sea level
• Defined at every point on the earth
1
Topog raphic da t a
So ho w did we get here?
• Topographic maps are
not new
• Let’s look at some
background
• Topographic data includes:
– Elevation data
– Features of the landscape
• Roads
• Rivers
• Land use / land cover
• Buildings
Techniques for represent ing
eleva tion
•
•
•
•
Vertical views
Oblique views
Draped images
Fly-by views
Conto ur lines are iso lines
• Isolines depict smooth, continuous
data
• Isolines connect points with equal
values of some attribute… elevation is
the most common
Ver t ical views of topo da ta
•
•
•
•
Conto ur lines
Contours
Hachures
Raisz’s Physiographic method
Shaded relief
Conto ur lines are “iso lines ”
• Isolines connect points with equal values of
some attribute… elevation is the most
common
• But other examples include:
– Temperature: isotherms
– Air Pressure: isobars
– Travel time: isochrones
– Any others?
2
Conto ur s
Tana ka ’s met ho d
• Connect points of equal elevation
• How are these determined?
• Chapter 14
•
Ha chures
• What are they?
This technique of applying a
northwest light source to a
contoured landscape was
first tried in 1850 but
printing methods then
could not handle gray
backgrounds (to be able to
highlight illuminated lines).
Ha chures
• What are they?
Tana ka ’s met ho d
• Altering the width of the contours as a
function of their angular relationship
with a light source
• Shadowed contours
Ha chures
• What are they?
• Small hashes drawn perpendicular to
contour lines
– Sometimes the width of the hash is in
proportion to the slope (slope hachures)
Ha chures
• What are they?
• Small hashes drawn perpendicular to
contour lines
RAIS Z ’S PHYSIOG RAPHIC METHOD
– Sometimes the width of the hash is in
proportion to the slope (slope hachures)
– Other times an oblique light source is
assumed… width used to depict shadow
(shadow contours)
3
Ra isz ’s Physio gr aphic Met ho d
• Erwin Raisz (1931)
• Landmarks of the United States
• Realistic pen and ink drawings of earth’s
features
• 15.2.3
Sha ded relief:
AKA hill sha ding
• Shaded Relief: Shaded relief is a
method for representing topography
on maps in a natural, aesthetic, and
intuitive manner.
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Sha ded relief: finally a good
def.
• Shaded Relief: Shaded relief is a
method for representing topography
on maps in a natural, aesthetic, and
intuitive manner.
The pio neer s of sha ded relief:
• Hans Conrad Gyger: In 1644, submitted this
early shaded relief to the Swiss government in
Zurich
• The painting took him 38 years
The pio neer s of sha ded relief:
• The map of the Zurich vicinity was at
1:32000
• Kept secret due to homeland security
• Comparable maps not created for 200 more
years
200 yea rs aft er Gyg er :
but st ill in Swit zer la nd
Gyg er ’s map is the precedent of sha ded
relief as a ca rt og raphic technique .
• Rudolf Leuzinger
– Colored shaded relief produced with
lithographic printing
• It truly is a
masterpiece
Im held’s 2 ma st er pieces
• 1887
• "Reliefkarte der
Centralschweiz"
• 1896
• "La Chaine du Mont
Blanc"
• Xaver Imheld
– 2 famous maps of swiss terrain
• "Reliefkarte der Centralschweiz"
• "La Chaine du Mont Blanc"
"L a Cha ine du Mo nt Bla nc"
Eduard Im ho f
Eduard Im ho f
• Swiss Federal Institute of Technology,
Zurich
• Famous for shaded relief on atlases
and school maps
5
Eduard Im ho f
Eduard Im ho f
H.C . Ber ann
• The panoramic map
• Austrian (1915-1999)
• Made beautiful artistic
renderings of terrain at
various cartographic
scales
Yosem it e
H.C . Ber ann
Join me for a sequence of images…
shall we?
Mo unt Ever est
Mo unt Fuji
Capr i
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Zur za ch and Rhein , Swit zer la nd
Denali
Tom Pa t ter so n
• American, works for National Parks
Service
• Enhances shaded relief with features
from aerial photography
Gra nd Tet o ns:Tom Pa tt er so n
Kenai Fjords: Tom Pa tt er so n
Last lect ur e
• Representing topography
• From above
• Major historical topo mappers
TODAY IN GEOG RAPHY 423
Wha t are the co mpo nent s?
• Designing shaded relief
– The components and their influences
• Alternatives to shaded relief
• Non-vertical topo representations
– Oblique views
– Draped images
– Fly-by views
DESIGNING SHADED REL IEF
The components and their
influences
• What
variables
control the
appearance
of shaded
relief?
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Wha t are the co mpo nent s?
• In other words what are the options in
the software (GIS)?
Sun Ang le
• Where do we put our fake sun?
Sun Ang le, AKA lig ht direct io n
– Sun Angle
– Ambient light
– Sun altitude
– Hypsometry
– Flooding
“No rt hwest er n illum inat io n ”
Normally the cartographer lets the light
"shine" on the terrain from the upper-left
Souther n Illum inat io n
Illum inat io n
• Normally the cartographer lets the light "shine" on
the terrain from the upper-left.
• Less popular is illumination from the south, as the
relief shading tends to not "look right".
• In extreme cases, relief inversion occurs where
mountains appear as valleys and vice versa
Illum inat io n ag ain
• If executed carefully, a shaded relief
with southern illumination may depict
the terrain with vivid and correct form.
However, maps with southern
illumination are generally more difficult
to read
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NW v. S illum na tio n
Ad justment of the Light
Direction
• Sometimes, tweaking the sun angle enhances the
clarity of the relief
• You don’t have to be so strict:
– Can adjust globally
– Tweak regionally
Sun Alt it ude
• How high in the sky is our fake sun?
• Sun altitude determines the
prevalence of shadows
• What happens as the angle
decreases?
Sun Ang le
•
•
•
•
How high in the sky is our fake sun?
Sun altitude determines the prevalence of shadows
What happens as the angle decreases?
As the sun angle decreases, more shadows
appear
• What would happen if it were 90 degrees? 0
degrees?
• What would be a good sun angle?
Sun Altitude us ually 45 deg rees
Am bient Light
• What it is ambient light?
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Am bient Light
• What it is ambient light?
• general brightness and contrast in the
shaded relief image
• independent of the solar azimuth and
elevation
Hypso m et ric tinting
• Hypsometry: measurement of the
elevation of land above sea level
• Hypsometric tinting: A method of
showing relief on maps and charts by
coloring in different shades those
parts which lie between selected
levels. Also called altitude tint;
elevation tint; layer tint.
Wh at about com bin ing
hyp som etric tintin g with
shaded relief ?
Good idea, or bad idea?
Hyps ometry + Shadin g = good idea
• What would happen if there were to be a flood?
Floo ding
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Techniques for represent ing
eleva tion
Ver t ical views of topo da ta
•
•
•
•
Contours
Hachures
Raisz’s Physiographic method
Shaded relief
•
•
•
•
• Figure 15.17
• A.K. Lobeck (1958)
• Block diagrams
• Panoramas
• Draped Images
Vertical views
Oblique views
Draped images
Fly-by views
Block Diag ram s
Block Diag ram s
• Hard to automate
– Book “Block Diagrams”
– Block Diagrams have two purposes:
– Extensive knowledge base required
– Subjective interpretation involved
• To present surface features
• To represent the underground structure
Ber ann ’s process
Oblique Views of Topog raphy
Ber ann ’s process
Pa no ra mas
•
•
•
•
•
Landscape views
“paintings that emphasize geography”
Berann is the most prominent
Formerly, artistic creations
More recently, digital creations
Beran n’s proces s (From Pa tterson ,
200 0)
• Referring primarily to contour maps, he sketched
the terrain of the park to appear in 3D.
• He did this without the aid of computers or
mechanical devices
• Drew radiating lines from a central observation
point
• These lines establish the field of view and serve as
guides for sketching the terrain in perspective.
11
Ber ann ’s Pr ocess
• Berann also referred to oblique aerial
photographs
– for the accurate depiction of vegetation,
mountain textures, cultural features, and
other surface details
Ber ann ’s Pr ocess
• Painting had 4 stages
1. light washes were applied over the
penciled line work to give basic color
and shape to landforms
Ber ann ’s Pr ocess
• Painting had 4 stages
3. lighter pigments were used to paint
highlights and surface details, and
greens were used to depict forest
and tundra vegetation
4.
Ber ann ’s process
The Pa nora ma as a Ca rtog raphic
Entity
• What are the pros and cons?
Ber ann ’s Pr ocess
•
1.
2.
Painting had 4 stages
light washes were applied over the penciled line
work to give basic color and shape to landforms
dark colors were applied to shadowed slopes
with broad brush strokes to develop further the
structure of landforms
Ber ann ’s Pr ocess
•
Painting had 4 stages
3. lighter pigments were used to paint highlights and
surface details, and greens were used to depict
forest and tundra vegetation
4. Rivers and the few roads that existed were painted
in last with a fine brush
The Pa nora ma as a Ca rtog raphic
Entity
• What are the pros and cons?
• Pros: Realistic, corresponds with the
way we naturally view topography.
Thus, more understandable than a
vertical perspective map
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The Pa nora ma as a Ca rtog raphic Entity
• What are the pros and cons?
• Pros: Realistic, corresponds with the
way we naturally view topography.
Thus, more understandable than a
vertical perspective map
• Cons: One-sided view, no scale, etc.
Pa no ra mas and com puter s
• Digital source: USGS
1:63000 DEM
• From
shadedrelief.com
• Tom Patterson, NPS
• Let’s compare
Phys ica l models of top og ra phy
Physica l Mo dels
• Truly congruent depictions of terrain
are impossible with paper maps and
computer screens
The last technique for visualizing
topography
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Phys ica l models of topog ra phy
• Truly congruent depictions of terrain
are impossible with paper maps and
computer screens
• Used to be very expensive and
laborious to create
• Now, cheaper and easier
Ho w are they made now?
• Based on DEM data
• Machines cut basic model out of foam
• Color images from satellites or aerial
photos are printed on the foam
Com puter s and Mo dels
• 1" = 100 meters (1:4000)
1:1 H:V
DEM furnished by SANDAG, 10 meter
grid
Image furnished by SANDAG, 2 ft CIR
aerial mosaic
Sum ma ry
• Represent topography in 3 main ways:
– Vertical Perspective
• Contours, tanaka, hachures, shaded relief
– Oblique Perspective
– Physical Models
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Sum ma ry
• Represent topography in 3 main ways:
– Vertical Perspective
• Contours, tanaka, hachures, shaded relief
– Oblique Perspective
• Block diagrams, panoramas, draped images
– Physical Models
• Attractive, but rare alternative to verticals and obliques
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