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Welcome Geomatics in the Classroom!. Power Point Presentation adapted by Claude Brun del Re. Canadian Space Agency. Agence spatiale canadienne. Ressources naturelles Canada. Natural Resources Canada. What is Geomatics ?. Geomatics for Educators. Geomatics.

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Geomatics in the Classroom!

Power Point Presentation adapted by Claude Brun del Re

Canadian Space Agency

Agence spatiale canadienne

Ressources naturelles


Natural Resources


geomatics for educators

What is Geomatics ?

Geomatics for Educators

  • Term originally created in Canada
  • Geomatics is the science and technology of gathering, analyzing, interpreting, distributing and using geographic information. Geomatics encompasses a broad range of disciplines that can be brought together to create a detailed but understandable picture of the physical world and our place in it. These disciplines include:
    • Mapping and Surveying
    • Geographic Information Systems (GIS)
    • Global Positioning System (GPS)
    • Remote Sensing
canada s role in geomatics
Canada’s Role in Geomatics
  • Canada exports ~ $300 million worth of geomatics products and services.
  • Growth rate of 15 to 20 per cent per year.
  • Demand for GIS products and services is expected to exceed $10 billion per year.
  • Geomatics is one of the fastest-growing technology sectors and Canada is a recognized leader, both in its development and in the provision of Geomatics software, hardware and value-added services.
  • Natural Resources Canada-
    • Geomatics Canada
      • Canada Centre for Remote Sensing
      • Centre for Topographic Information
      • Aeronautical Charts & Technical Services
      • Legal Surveys & International Boundary Commission
      • Geodetic Survey
list examples of remote sensing technology in your every day life
Satellite weather maps


Speed radar

Sonar (for ships, bats or dolphin)


CAT scans


List examples of remote sensing technology in your every day life
remote sensing
Definition and Process




Electromagnetic Energy



remote sensing a definition
Remote Sensing - A Definition

Indirect (remote) observations (sensing)

Remote sensing is the science (and to some extent, art) of acquiring image data and deriving information about the Earth’s surface without actually being in contact with it.

Remote sensing will give information about an object called

a target


Space shuttle



Ground base tower

How does remote sensing work?Far away from the target, on what we call a platform.Here are some types of platform
remote sensing process
Remote Sensing Process
  • Energy Source or Illumination (A)
  • Radiation and the Atmosphere (B)
  • Interaction with the Target or Surface (C)
  • Recording of Energy by the Sensor (D)
  • Transmission, Reception, and Processing (E)
  • Interpretation and Analysis (F)
  • Application (G)
passive sensor
Passive Sensor
  • Passive sensors detect or “sense” reflected solar radiation

What does a passive sensor need

to sense the earth?

active sensors
Active Sensors
  • Active sensors produce and receive their own electromagnetic energy

They produce their own illumination and they

operate in the microwave region

some atmospheric interactions
Some Atmospheric Interactions
  • Energy will interact with the atmosphere on its way in and out
  • Ozone, nitrogen, CO2 and water vapour affect incoming energy
  • Energy affected if wavelength is < or = the particle size
  • Atmospheric windows are

wavelengths not affected by

the atmosphere

  • Some substances absorb certain wavelengths of energy
  • UV rays absorbed by ozone
  • LW IR and SW microwaves absorbed by water vapour
  • These wavelengths are not suitable for remote sensing


  • Occurs when molecules are larger or equal to wavelength
  • Rayleigh scattering - selective scattering (UV, Blue sky)
  • Non-selective - scatters all visible wavelengths (clouds)
terrain interactions
Terrain Interactions
  • Radiation that reaches the Earth’s surface can be: Absorbed (A); Transmitted (T); and Reflected (R).
  • This will vary with the type of object. The type of interaction will depend on the wavelength of the energy and the material and condition of the feature.
  • Look at different objects, for example an egg, a green apple and a tomato.
diffuse and specular reflectors
Diffuse and Specular Reflectors

Diffuse Specular

rough surface smooth surface

electromagnetic energy



Gamma Ray





0.003nm 0.03nm 0.3nm 3nm 30nm 0.3

m 3

m 30

m 300

m 0.3cm 3cm 30cm 3m 30m

Electromagnetic Energy
  • Electromagnetic energy is used to illuminate the target in remote sensing
  • Electromagnetic spectrum:

Shorter wavelength Longer wavelength

visible spectrum
Visible Spectrum

Visible Wavelegths

  • Violet: 0.4 - 0.446 mm
  • Blue: 0.446 - 0.500 mm
  • Green: 0.500 - 0.578 mm
  • Yellow: 0.578 - 0.592 mm
  • Orange: 0.592 - 0.620 mm
  • Red: 0.620 - 0.7 mm
ir and microwaves
IR and Microwaves
  • Reflected IR: 0.72 mm to 3.0 mm
  • Thermal IR:3.0 mm to 15 mm
  • Microwaves:1 mm to 1 m
visible infrared vir
Visible / Infrared (VIR)
  • Colours we perceive are combinations of electromagnetic energy
  • VIR (visible infrared) or optical sensors capture energy reflected by targets in the optical and IR wavelengths
  • Each target reflects or emits these types of energy in different amounts
spectral response
Spectral Response
  • Different objects reflect, absorb and transmit energy in differing amounts
  • An object also transmits, reflects, and absorbs each wavelength differently
  • Spectral responses enable us to identify different objects on images
  • An object’s spectral response may change over time
spectral response leaves
Spectral Response - Leaves
  • Chlorophyll absorbs red and blue
  • Reflects green
  • Greenest in summer
  • Internal leaf structure reflects near IR
bands or channels
Bands or Channels
  • Each sensor has a purpose (vegetation, ocean, ice, weather)
  • Certain wavelengths provide more information about certain targets
  • To perform their tasks, sensors on satellites detect energy in very specific, narrow bands or channels of electromagnetic energy
spatial resolution
Spatial Resolution

Fine Resolution Coarse Resolution

  • Total field of view
  • Width of the image in ground distance
  • For satellites, variesbetween 10s to 100sof kilometres
  • Geostationary Near-polar sun-synchronous
  • Geostationary Operational Environmental Satellite
  • Operated by NOAA to for weather forecasting and monitoring
  • 5 spectral bands (green-red to infrared)
  • Geostationary above the equator at 75 degs E and W
  • Resolution 1 to 4 kilometres
noaa avhrr
  • Advanced Very High Resolution Radiometer
  • Used for meteorology and other applications (vegetation)
  • Sun-synchronous, near-polar orbits(830-870 km above the Earth)
  • Ensure that data for any region of the Earth is no more than six hours old
  • visible, near, mid infrared,& thermal IR
  • 3000 km swath, 1 to 4 km resoloution
  • Landsat-1 was launched by NASA in 1972
  • Landsat 7 was launched in 1999
  • ETM (Enhanced Thematic Mapper) 8 bands VIR and Thermal IR
  • 30 metre resolution
  • 185 kilometre swath width
  • Lots of archived data
  • Near-polar, sun-synchronous orbits - 705 km
  • Système Pour l’Observation de la Terre
  • French commercial satellites
  • SPOT 1 -1986
  • SPOT -2 operational, SPOT-4 just launched
  • Sun-synchronous, near-polar orbits at altitudes around 830 km
  • 2 Sensors MLA and PLA
  • PLA - black and white
  • MLA - 3 visible bands (blue-green-red)
  • 60 to 80 km swath
  • 10 to 20 m resolution
radarsat 1
  • Canada’s first earth observation satellite
  • Launched November 4, 1995
  • Monitoring the Arctic (ice) is its main role
  • Unique, flexible, “steerable” sensor
  • Many swath width choices
  • Many incidence angles available
radarsat 11

Orbit Geometry

- Circular, Near polar

- Sun-synchronous


- 98.6° (from the equator)

-Passes to the right of the North Pole


- 100.7 Minutes

Repeat Cycle

- 24 days

- 14 orbits per day


- Global: 4,5 days

- North America: 3 days

- Arctic: daily


- 798 km

new small sats
New Small Sats
  • 1 to 5 metre resolution
  • All commercially built
  • Earlybird
  • QuickBird
  • RADAR is an acronym for RAdio Detection And Ranging
  • A microwave (radio) signal is transmitted towards the target
  • The sensor detects the reflected (or backscattered) portion of the signal
radar images
RADAR Images
  • Radar images “look” like black and white photographs
  • Tones of gray correspond to the amount of radar energythat is returned to the sensor
  • The stronger the backscatter or the more energy that is returned to the sensor, thelighter that area or object will appear on the final image
radar reflection
RADAR Reflection
  • There are three general types of reflection:speculardiffusecorner


  • Own energy source (images anytime of day)
  • “Sees” through clouds (images anywhere)
  • Provides good view of topography
  • Sensitive to surface roughness
  • Provides information on moisture content
  • Side-looking geometry creates distortions
  • Radar speckle
  • Excessive loss of data in mountainous areas due to shadows
radar sensors
Radar Sensors
  • SEASAT - NASA 1978
    • lasted only a few months
  • ERS-1 - ESA 1991-95
    • 30 metre resolution
  • ERS-2 - ESA 1994
    • 30 metre resolution
  • JERS-1 - Japan 1992
    • 18 metre resolution
what is an image
What is an Image?
  • Image is a visual view of the energy reflected by the target
  • Satellite images are digital: they are made up of numbers usually from 0 to 255 where 0 is black and 255 is white
  • The numbers (radiance value) are arranged in rows and columns
  • Each square is called a PIXEL
  • A number or a value of reflected energy is stored for each pixel
raster data
Raster Data
  • Images are stored as raster data - grid of cells or pixels
  • Each pixel represents a certain amount of ground like 10 m x 10 m
  • Each pixel is representative of the amount of energy backscattered by the target
pixels and lines
Pixels and Lines
  • Upper left corner is the origin
  • X values are pixels or columns
  • y values are lines or rows
pixels and lines1
Pixels and Lines

Pixels Lines

X= Pixel 2 and Line 2 ( 2, 2)


bits and bytes
Bits and Bytes
  • Bits are binary digits (0 or 1)
  • Images are collected as 8, 16, 32 bit data
  • Bit refers to the number of exponential levels a binary digit is taken to
    • single bit = 21
    • 8 bit = 28 or 256 levels of grey
    • 16 bit = 216 or 65536 levels of grey
image file formats
Image File Formats
  • .pix = PCI or Eoscape
  • .img = ERDAS Imagine
  • .lan = ERDAS
  • GeoTIFF .tiff = contains georeferencing info
  • TIF = requires header file for georeferencing
  • .bil, ,bsq, raw = flat raster, common format, needs header file
  • jpeg = common image format for the WWW, no georeferencing information
  • GRID = ESRI raster format
vir images
VIR Images
  • Usually 3 bands loaded
  • One band loaded aloneappears as a greyscale
  • Each assigned a colourgun (Blue, green, red)
  • Together, 3 bands formcolour image