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 (horning@amnh.org) 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. (kseto@stanford.edu) 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. (gary.n.geller@jpl.nasa.gov) ) 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