EGM101 Skills Toolbox

1/21/16
EGM101 Skills Toolbox
Weeks 1-3: Spatial Mapping
PDF versions of these lecture notes (weeks 1-3) are available
on the dedicated site:
http://rqmodules.weebly.com/egm101.html
• Map-making dates back to the Stone Age and appears to predate written
language by several millennia.
• A map is a simplified depiction of a space which highlights relations
between components (natural and manmade) of that space.
• One of the oldest surviving maps is painted on a wall of the Catal Huyuk
settlement in south-central Anatolia (now Turkey) approx. 8,200 years old.
• Most usually a map is a two-dimensional, geometrically accurate
representation of a three-dimensional space; e.g., a geographical map.
• Spatial mapping used in all the earth sciences (geology, environmental,
geography, marine, fresh water).
• You will use maps throughout your degree courses and in your future careers
as a standard technique, often as the ‘baseline’ for field-based and desktop
assessments of the environment.
City plan of Çatal Höyük. Recreation of the original plan, where you can appreciate the
structure of the city. An erupting volcano also appears - probably the Hasan Dag, still visible from
Çatal Höyük in the present time.
• Modern mapping techniques exploit the recent advance in powerful and
affordable desktop computing facilities and linear electronics to map the surface
and sub-surface of the earth.
• Digital age – digital generation - digital data.
• Common example – data available from Google Earth.
• From the last quarter of the 20th century, the indispensable tool of the
cartographer has been the computer.
• Much of cartography, especially at the data-gathering survey level, has been
subsumed by Geographic Information Systems (GIS).
• The functionality of maps has been greatly advanced by technology allowing, for
example, the superimposition of spatially located variables onto existing
geographical maps.
• As field-based scientists we use digital technology to acquire, process, integrate
and aid interpretation of spatial data.
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Spatial Data
Spatial data is often accessed, manipulated or analyzed through
Geographic Information Systems (GIS).
Sula Reef – Norwegian shelf
Su rvey of Norway, 2 0 0 4
Spatial data is usually stored as coordinates and topology, and is data
that can be mapped.
NASA satellite – Mars surface
Geological
Also known as geospatial data or geographic information it is
the data or information that identifies the geographic location of
features and boundaries on Earth, such as natural or constructed
features, oceans, and more.
Example – how ‘mapping’ technology has advanced in the past 20 years.
ADUSurvey, 2006
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• Cartography is the art, science, and technology of creating maps.
• The use of scale allows a cartographer to graphically represent a
geographic area.
• Maps are usually 2-dimensional representations of 3- dimensional
landscapes.
• To portray meaningful relationships for a complex, 3-dimensional world
on a flat sheet of paper, a map distorts reality.
• As a scale model, the map must use symbols that are usually bigger or thicker
than the features they represent.
• To avoid hiding critical information in a fog of detail, the map must offer a
selective, incomplete view of reality.
• The cartographic paradox - to present a useful and truthful picture, an
accurate map must tell white lies.
• All maps have some basic features in common;
• Map reading is all about learning to understand their particular language.
Maps have 3 basic attributes:
• scale;
• projection, and
• symbolisation.
Map Scale
• Map scale is defined as the ratio between map distance to
earth distance.
• Small scale maps show large geographic areas, showing
less detail.
• Large scale maps show small geographic areas, showing
more detail.
Essential to understand all three to interpret and make maps.
1:25,000 scale
1cm measured on the map is
equal to 250m in the real world.
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Map Projection
Map Symbols
• A map projection is any method used in cartography
(mapmaking) to represent the two-dimensional curved surface of
the earth or other body on a plane (one-dimensional) surface.
• The term projection here refers to any function defined on the
earth's surface and with values on the plane.
• Accurate and well produced maps will not only help in the
• Throughout your degree and in your career, you will end up
using a variety of maps to plan and conduct fieldwork and to
map the data you collect.
• Maps are used throughout the degree course for the majority of
field exercises.
presentation of field results, but will also help in creating a
professional piece of work.
• Here are a list of basic points which should be taken into
account in map production:
• Additionally, the production of appropriate base maps is an
important skill in preparing a report or dissertation.
• You may be able to: buy maps, copy maps from existing
(1) All maps should have a title (or figure caption), scale,
sources (ensure you have permission to reproduce them as most
orientation (north arrow) and a key defining the symbols
maps are copyrighted), modify existing maps, or you may have
to conduct a survey and present the results as a map.
used.
2) Do not clutter a map by including too much information.
Present the relevant information.
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3) Always ensure there is a point of reference on the map.
Ideally this would consist of grid references. If this is not
possible, then use inset key maps to establish the location.
4) Labels should be parallel to the text and to each other. River
names can run parallel to the river in question.
5) If you use a previously published map, then it should always
be referenced:
(a) Where the source is an Ordnance Survey map:
Ordnance Survey (1988) Preston and Blackpool, Sheet 102,
1:50,000. (Landranger series).
(b) Where the source is a Geological map:
Geological Survey of Great Britain (England and Wales)
(1972). Alnwick, (drift), Sheet 6, 1:50,000.
Geographic Information System (GIS)
6) Different font sizes and line weighting can be used
effectively. Be consistent when varying lines and font sizes.
Important information for Wednesday’s practical
Wednesday, TL5, 09.15-13.15
• Group 1: Surnames Ali-McClean, 09.15-11.15
• Group 2: Surnames McCluskey-Young, 11.15-13.15
Web GIS example
http://gis.epa.ie/Envision
Tasks
• Read assignment details http://rqmodules.weebly.com/egm101.html
• Print basemap and bring to practical
• Bring pencil, eraser, ruler, and calculator
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