, GEOGRAPHIC INFORMATION SYSTEMS [GIS]
GIS → computerized system consisting of or hardware, software, data, people &
methods designed to read in, manage, manipulate, analyse, model and display spatial
geographic data and non-spatial geographic data solve complex planning and
management problems
• Geography: Study of the real world. Physical and cultural world with its spacing
patterns of people, the environment, and their interaction with each other.
• Information: Set of processes that use raw data to compile information that can
be used in decision-making processes
• Systems: group of related objects and activities that interact with each other
HISTORY OF GIS:
NOTES:
1800s → hand drawn maps > propose &
u Save geographic data in digital analyse groups of geographic
format → computer dependent phenomena = labour
u specific data transferred by intensive & time consuming
a user Early 1900s = beginning of mass printing of
graphics
u government, industries, land
→ colours = each on different
planners, home affairs, public printing plate
sector offices and private → different types of map
users information on different layers
u People = key role in the Mid 1900s = development of computer
hardware & software
development of GIS
→ maps = separate transparent
software that captures plastic layers produced &
important geographic superimposed = compare
information geographical phenomena
u Geographers → plan (where to → nuclear weapons research =
general computer cartography
develop new settlements,
applications
build dams), where to act
1955 – 1960 = space race begins
(address high levels of u Russia = Sputnik 1 > 1957
pollutants in a conservation u USA = Explorer 1 > 1958
area) and evaluate (the u Development of Global Navigation
Satellite Systems
effects of acid mine water
1960 = first GIS
on local residents)
u Tomlinson = father of GIS > 1960
u Use → constantly expanded = DATA store for Canadian Land
by new data and new Inventory [1 : 50,000 scale]
technology u Harvard 1966 > Grid based mapping
program
u specific and adapted data or
u 1970 = private companies sell GPS
information
u World Geodetic System > 1984
1990 = GIS commonly used by national &
provincial government sectors
2010+ = ICT > GIS by Google & GPS (Global
Positioning System)
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, THE VALUE OF DIGITAL DATA
u ↑ amount of information that can be collected, stored, analysed, and displayed
u information = computer system stored and manipulated in numerical form [number,
letter, and colour = numerical code]
u Information = easily selected, sorted, and displayed graphically
REMOTE SENSING
→ science that gathers information about the earth's surface without actually being in
contact with it [reflections / radiated energy > detect & register → process, analyse &
apply information]
7 ELEMENTS:
1. Sun = source of electromagnetic energy
2. Solar energy = waves > move through atmosphere [satellites = energy (radio waves)]
3. Energy = earth surface > wavebands & interaction with surface [absorbed, emitted,
reflected]
4. Remote sensors = energy in different wavebands detected & corrected information
5. Energy information = electronic signals → ground station (convert information > maps >
satellite images)
6. People → satellite images = information about earth
7. Maps / models = develop new knowledge about the area / help solve environmental
problems
ELECTROMAGNETIC ENERGY SATELLITES & SENSORS
→ wavelengths = bands → each = sensors > detect information
→ sensors on satellites = detect energy outside
visible spectrum
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, AERIAL PHOTOS; ORTHOPHOTO MAPS ; SATELLITE IMAGES
DIFFERENT TYPES OF IMAGES:
GIS HORIZONTAL PHOTO
→ spatial information > images : → camera = horizontal on subject
referenced using survey technicians & GPS
OBLIQUE AERIAL PHOTO SATELLITE IMAGE
→ aerial camera taken between horizontal → digital pictorial image from remote
/ vertical > shows side views & easy sensing data > sensors to satellites
identification of terrain landmarks
LOW ANGLE AERIAL PHOTO VERTICAL AERIAL PHOTO
→ ground-surface visible ( horizon ) → camera = below plane > directly
→ camera axis = 30° from vertical overhead
HIGH ANGLE AERIAL PHOTO → terrain beacons = correct spatial
→ ground-surface features + horizon relationship
visible → top view only (phenomena )
→ camera axis = 60° from vertical → camera axis = 90° vertical to ground
USES : VERTICAL AERIAL PHOTOS, ORTHOPHOTOS & SATELLITE IMAGES [MAPPING]:
VERTICAL AERIAL PHOTOGRAPHS
→ Overlapping photos > taken vertically above the ground →
specially adapted camera
→ Thousands of photos > plane = planned route
→ used to create topographic maps
→ larger scale than topographic maps = phenomena larger
ADVANTAGES DISADVANTAGES DEVELOPMENT
u Source of spatial data → u The scale = only correct u Cameras = automated +
mapping in the middle film quality ↑
u Available in different u most images = black and u Photos → camera film
scales white developed = no longer
u Collection = historical u Must be scanned & used so much for
record of photographs > digitized = mapping mapping maps
monitor settlements,
economic growth, and
development → 1930
ORTHOPHOTOS & ORTHOPHOTO MAPS
→ many vertical aerial photographs that partially
overlapped each other = scale-correct images
→ by adding map information to orthophotos
→ Orthophoto map = combination of a map and a
photograph
→ larger scale (1:10 000) than the topographical map
= phenomena larger
→ contour lines superimposed on it > sense of the
relief of the landscape = essential information
provided
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