Learning From Paper: Using Learning From Paper: Using Printed Satellite Images as a Printed Satellite Images as a Conservation and Ecosystem Conservation and Ecosystem
Management ToolManagement Tool
A class delivered at the
3rd IUCN World Conservation Congress
17-25 November 2004
Bangkok, Thailand
Ned Horning (Ned Horning ([email protected]) Remote Sensing/GIS Program ManagerRemote Sensing/GIS Program ManagerCenter for Biodiversity and Center for Biodiversity and ConservationConservationAmerican Museum of Natural HistoryAmerican Museum of Natural History
Karen C. Seto, Ph.D. (Karen C. Seto, Ph.D. ([email protected]) Assistant ProfessorAssistant ProfessorDepartment of Geological and Environmental Department of Geological and Environmental Sciences, andSciences, andCenter for Environmental Science and PolicyCenter for Environmental Science and PolicyStanford University, andStanford University, andEcosystem Management Tools Thematic LeaderEcosystem Management Tools Thematic LeaderCommission for Ecosystem Management, IUCNCommission for Ecosystem Management, IUCN
Gary N. Geller, Ph.D. (Gary N. Geller, Ph.D. ([email protected]) ) ASTER Conservation LiaisonASTER Conservation LiaisonJet Propulsion LaboratoryJet Propulsion LaboratoryCalifornia Institute of TechnologyCalifornia Institute of Technology
Prepared and presented by:
OvervieOvervieww
Remote sensing overview Remote sensing overview Value and limitations of working Value and limitations of working
with paper imageswith paper images Visual interpretation methodsVisual interpretation methods Hands-on image exploration and Hands-on image exploration and
interpretationinterpretation Discussion of applications where Discussion of applications where
printed images can be used printed images can be used effectivelyeffectively
Wrap-upWrap-up
How can satellite images helpHow can satellite images helpconservation practitioners?conservation practitioners?
Observe:Observe: land cover, boundaries, threats, land cover, boundaries, threats, damage, topography…damage, topography…
Monitor:Monitor: change in forest cover, range change in forest cover, range condition, land use…condition, land use…
Classify:Classify: into vegetation and land use into vegetation and land use categories, habitats…categories, habitats…
Measure:Measure: areas, distances, areas, distances, height/elevation…height/elevation…
Detect: Detect: fires, resource use violations…fires, resource use violations…
Highlights of Earth Remote Highlights of Earth Remote SensingSensing
Before 1972 - primarily aerial and Before 1972 - primarily aerial and satellite photographssatellite photographs
1972 - First Landsat satellite 1972 - First Landsat satellite launchedlaunched
1978 - SPOT satellite launched1978 - SPOT satellite launched 1988 - Indian Remote Sensing 1988 - Indian Remote Sensing
Satellite launchedSatellite launched 1995 - Radarsat launched1995 - Radarsat launched 1999 - IKONOS satellite launched 1999 - IKONOS satellite launched
and NASA launched Terra satelliteand NASA launched Terra satellite Today many new satellite and Today many new satellite and
airborne instruments are being airborne instruments are being developed and launcheddeveloped and launched
An image is made up of individual elements called An image is made up of individual elements called pixels that are arranged in a grid of rows and pixels that are arranged in a grid of rows and columns.columns.
The sensor acquires several images (bands) at The sensor acquires several images (bands) at once, each recording a specific color or range of once, each recording a specific color or range of colors. When viewed, each individual band looks colors. When viewed, each individual band looks like a black and white photographlike a black and white photograph
Landsat band 2 - (wavelength range = 0.52-0.60 µm = blue light)
Electromagnetic Spectrum
Source: http://observe.ivv.nasa.gov/nasa/education/reference/reflect/ir.html
For each band the intensity of energy for a specific range of wavelengths (colors) is measured
Spectral signaturesSpectral signatures
RGB Band CompositeRGB Band Composite
Pixel color and brightness is Pixel color and brightness is determined by the pixel value determined by the pixel value
Certain bands or band combinations are better than others for Certain bands or band combinations are better than others for identifying specific land cover features.identifying specific land cover features.
Landsat TM Red= band 3, Green = band 2, Blue = band 1
Landsat TM Red= band 4, Green = band 5, Blue = band 4
Landsat ETM+ band 1 (0.45-0.52 µm, blue-Landsat ETM+ band 1 (0.45-0.52 µm, blue-green)green)
Penetrates water better Penetrates water better than the other bands so it than the other bands so it is often the band of choice is often the band of choice for aquatic ecosystemsfor aquatic ecosystems
Used to monitor sediment Used to monitor sediment in water, mapping coral in water, mapping coral reefs, and water depthreefs, and water depth
The “noisiest” of the The “noisiest” of the Landsat bands since short Landsat bands since short wavelength blue light is wavelength blue light is scattered more than the scattered more than the other bandsother bands
Rarely used for "pretty Rarely used for "pretty picture" type images picture" type images
Landsat ETM+ band 2 (0.52-0.60 µm, green)Landsat ETM+ band 2 (0.52-0.60 µm, green)
Similar qualities to Similar qualities to band 1 but not as band 1 but not as noisy. noisy.
Matches the Matches the wavelength for the wavelength for the color green.color green.
Landsat ETM+ Landsat ETM+ bandband 3 (0.63-0.69 µm, 3 (0.63-0.69 µm, red)red)
Since vegetation Since vegetation absorbs nearly all red absorbs nearly all red light (it is sometimes light (it is sometimes called the chlorophyll called the chlorophyll absorption band) this absorption band) this band can be useful for band can be useful for distinguishing distinguishing between vegetation between vegetation and soil and in and soil and in monitoring vegetation monitoring vegetation healthhealth
Landsat ETM+ band 4 (0.76-0.90 µm, near Landsat ETM+ band 4 (0.76-0.90 µm, near infrared)infrared)
Since water absorbs Since water absorbs nearly all light at this nearly all light at this wavelength water bodies wavelength water bodies appear very dark. This appear very dark. This contrasts with bright contrasts with bright reflectance for soil and reflectance for soil and vegetation so it is a good vegetation so it is a good band for defining the band for defining the water/land interfacewater/land interface
Sensitive to vegetation Sensitive to vegetation covercover
Less affected by Less affected by atmospheric atmospheric contaminationcontamination
Landsat ETM+ band 5 (1.55-1.75 µm, mid-Landsat ETM+ band 5 (1.55-1.75 µm, mid-infrared)infrared)
Very sensitive to Very sensitive to moisture and is moisture and is therefore used to therefore used to monitor vegetation monitor vegetation water stress and soil water stress and soil moisture. moisture.
Useful to Useful to differentiate between differentiate between clouds and snowclouds and snow
Landsat ETM+ band 6 (10.40-12.50 µm, thermal Landsat ETM+ band 6 (10.40-12.50 µm, thermal infrared)infrared)
Measures surface Measures surface temperature. temperature.
Geological Geological applications applications
Differentiate clouds Differentiate clouds from bright soils since from bright soils since clouds tend to be very clouds tend to be very coldcold
The resolution is twice The resolution is twice as course as the other as course as the other bands (60 m instead bands (60 m instead of 30 m) of 30 m)
Landsat ETM+ band 7 (2.08-2.35 µm mid-Landsat ETM+ band 7 (2.08-2.35 µm mid-infrared)infrared)
Can detect high Can detect high surface temperaturessurface temperatures
Also used for Also used for vegetation moisture vegetation moisture although generally although generally band 5 is generally band 5 is generally preferred for that preferred for that applicationapplication
Commonly used in Commonly used in geologygeology
Landsat ETM+ bands 3,2,1 Landsat ETM+ bands 3,2,1 – Penetrates shallow water – Penetrates shallow water and shows submerged and shows submerged shelf, water turbidityshelf, water turbidity
Landsat ETM+ bands Landsat ETM+ bands 4,3,2 – Peak chlorophyll, 4,3,2 – Peak chlorophyll, land/water boundary, land/water boundary, urban areasurban areas
Landsat ETM+ bands 4,5,3 Landsat ETM+ bands 4,5,3 – Land/water boundary, – Land/water boundary, Vegetation type and Vegetation type and condition, soil moisturecondition, soil moisture
Landsat ETM+ bands 7,4,2 Landsat ETM+ bands 7,4,2 – Moisture content in – Moisture content in vegetation and soils, vegetation and soils, geological mapping, geological mapping, vegetation mappingvegetation mapping
MODIS (500m) – Composited using imagery acquired from June – September 2001
Landsat ETM+ (30m) - 2 April Landsat ETM+ (30m) - 2 April 20022002
ASTER (15m) - 8 November ASTER (15m) - 8 November 20032003
CORONA (5m) – 4 March 1967CORONA (5m) – 4 March 1967
IKONOS (1m) – 29 April 2002IKONOS (1m) – 29 April 2002
IKONOS zoomedIKONOS zoomed
Advantages of using paper Advantages of using paper imageryimagery
No need for a computer or fancy No need for a computer or fancy equipmentequipment
Inexpensive to createInexpensive to create Very portable and easy to carry in Very portable and easy to carry in
the fieldthe field Easy to show other people and often Easy to show other people and often
a more effective communication toola more effective communication tool Looks nice on the wallLooks nice on the wall
Limitations of using paper Limitations of using paper imageryimagery
Ancillary data obscures image dataAncillary data obscures image data Not possible to zoom into the imageNot possible to zoom into the image Not possible to change the image Not possible to change the image
enhancementenhancement Can not easily overlay other data Can not easily overlay other data
layerslayers Generally more difficult to locate Generally more difficult to locate
oneself on the image since GPS oneself on the image since GPS tracking is not possibletracking is not possible
Visual Interpretation SkillsVisual Interpretation Skills
How to read a satellite imageHow to read a satellite image
What do you need to interpret What do you need to interpret remotely sensed imagery?remotely sensed imagery?
Familiarity with the specific area or similar Familiarity with the specific area or similar areasareas
Basic interpretation skillsBasic interpretation skills Image prints that are of sufficient qualityImage prints that are of sufficient quality Projection grid marks on the image are Projection grid marks on the image are
helpful to locate oneself on the image using helpful to locate oneself on the image using a GPSa GPS
Equipment to protect the imagery if working Equipment to protect the imagery if working in the fieldin the field
Tools to transcribe information onto the Tools to transcribe information onto the imageimage
Basic Elements of Visual Basic Elements of Visual InterpretationInterpretation
Tone (color)Tone (color) Size and shapeSize and shape Texture and patternTexture and pattern Relative and absolute locationRelative and absolute location ShadowsShadows
Tone and ColorTone and Color
Variations in tone and Variations in tone and color results in all of color results in all of the other visual the other visual elementselements
When looking at a When looking at a image photo we image photo we associate specific tones associate specific tones to particular featuresto particular features
Tones change when we Tones change when we enhance an image or enhance an image or when we change the when we change the band combination of a band combination of a color imagecolor image
Size and ShapeSize and Shape
Rectangular features often Rectangular features often indicate human influence indicate human influence such as agriculturesuch as agriculture
Size and shape Size and shape information greatly information greatly influenced by image influenced by image resolutionresolution
Knowing the scale of the Knowing the scale of the image helps to convert image helps to convert feature dimensions on the feature dimensions on the image to actual image to actual dimensionsdimensions
Texture and PatternTexture and Pattern
Varies with image Varies with image resolutionresolution
Often noted by Often noted by roughness or roughness or smoothnesssmoothness
Influenced by Influenced by shadowsshadows
Relative and Absolute LocationRelative and Absolute Location
The location of a The location of a feature narrows feature narrows the list of possible the list of possible cover typescover types
Relative location Relative location particularly useful particularly useful to determine land to determine land use use
ShadowsShadows Often considered a Often considered a
contaminant but can be contaminant but can be very useful to identify very useful to identify features on an imagefeatures on an image
Helpful to accentuate Helpful to accentuate reliefrelief
Shadow effects change Shadow effects change throughout the day and throughout the day and throughout the yearthroughout the year
Shadows can give an Shadows can give an indication to the size of indication to the size of a particular featurea particular feature
ExercisesExercises
Purpose: Give you a change to do some of Purpose: Give you a change to do some of what we just talked aboutwhat we just talked about
After the break we will:After the break we will: Explore different satellite imagesExplore different satellite images Identify features on printed satellite imagesIdentify features on printed satellite images Relate features in the image with features in a Relate features in the image with features in a
photographphotograph Draw lines around features we can see in the Draw lines around features we can see in the
satellite imagessatellite images
Supplies that will be used in Supplies that will be used in classclass
Imagery (Landsat ETM+ ASTER, Imagery (Landsat ETM+ ASTER, Corona, IKONOS, ground photo)Corona, IKONOS, ground photo)
Topographic mapTopographic map TransparenciesTransparencies Masking tapeMasking tape Black markerBlack marker CottonCotton AlcoholAlcohol
ExercisesExercises
DiscussionDiscussion
Questions, additions, and Questions, additions, and clarifications…clarifications…
Wrap UpWrap Up
What have we learned?What have we learned? Where satellite images come from and Where satellite images come from and
what they are made ofwhat they are made of How to interpret imagesHow to interpret images Methods for using images as an aid to Methods for using images as an aid to
conservation managementconservation management After this classAfter this class
Find some images for your area (use Find some images for your area (use handout)handout)
Play with them using some of the Play with them using some of the techniques we discussedtechniques we discussed