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Studying Polar Change Studying Polar Change with Digital Imageswith Digital Images
Studying Polar Change Studying Polar Change with Digital Imageswith Digital Images
John PickleJohn Pickle
Concord Academy, Concord, MAConcord Academy, Concord, MA
[email protected] [email protected]
oror
[email protected] [email protected]
John PickleJohn Pickle
Concord Academy, Concord, MAConcord Academy, Concord, MA
[email protected] [email protected]
oror
AgendaAgendaAgendaAgenda
Overview of Goals & ActivitiesOverview of Goals & Activities
Basics of Color, Digital Images, & MapsBasics of Color, Digital Images, & Maps
Spatial MeasurementsSpatial Measurements
Enhancing Colors to See PatternsEnhancing Colors to See Patterns
Masking Colors to Isolate PatternsMasking Colors to Isolate Patterns
Putting it all together to study Putting it all together to study
changechange
Overview of Goals & ActivitiesOverview of Goals & Activities
Basics of Color, Digital Images, & MapsBasics of Color, Digital Images, & Maps
Spatial MeasurementsSpatial Measurements
Enhancing Colors to See PatternsEnhancing Colors to See Patterns
Masking Colors to Isolate PatternsMasking Colors to Isolate Patterns
Putting it all together to study Putting it all together to study
changechange
Goals of ActivitiesGoals of ActivitiesGoals of ActivitiesGoals of Activities
Maps and images are spatial Maps and images are spatial
representation of datarepresentation of data
Software allows rapid & Software allows rapid &
efficient access to the dataefficient access to the data
Emphasize “big” ideas & Emphasize “big” ideas &
flexible applicationflexible application
Maps and images are spatial Maps and images are spatial
representation of datarepresentation of data
Software allows rapid & Software allows rapid &
efficient access to the dataefficient access to the data
Emphasize “big” ideas & Emphasize “big” ideas &
flexible applicationflexible application
Color - Light vs PaintColor - Light vs PaintColor - Light vs PaintColor - Light vs Paint
Mixing all of your paints in your Mixing all of your paints in your paint set produced what color?paint set produced what color?
Putting white light through a Putting white light through a prism produces what?prism produces what?
Explore Explore subtractivesubtractive and and additiveadditive colors using ColorBasics softwarecolors using ColorBasics software
Mixing all of your paints in your Mixing all of your paints in your paint set produced what color?paint set produced what color?
Putting white light through a Putting white light through a prism produces what?prism produces what?
Explore Explore subtractivesubtractive and and additiveadditive colors using ColorBasics softwarecolors using ColorBasics software
ColorColor Red ValueRed Value Green ValueGreen Value Blue ValueBlue Value
BlackBlack 0%0% 0%0% 0%0%
WhiteWhite 100%100% 100%100% 100%100%
RedRed 100%100% 0%0% 0%0%
YellowYellow 100%100% 100%100% 0%0%
GreenGreen 0%0% 100%100% 0%0%
CyanCyan 0%0% 100%100% 100%100%
BlueBlue 0%0% 0%0% 100%100%
MagentaMagenta 100%100% 0%0% 100%100%
OrangeOrange 100%100% 50%50% 0%0%
PurplePurple 50%50% 0%0% 70%70%
BrownBrown 70%70% 40%40% 15%15%
PinkPink 100%100% 80%80% 80%80%
Light GrayLight Gray 75%75% 75%75% 75%75%
Medium GrayMedium Gray 50%50% 50%50% 50%50%
Dark GrayDark Gray 25%25% 25%25% 25%25%
Red 62%Red 62%Green 71%Green 71%Blue 11%Blue 11%
Red 51%Red 51%Green 41%Green 41%Blue 35%Blue 35%
Red 12%Red 12%Green 11%Green 11%Blue 11%Blue 11%
Pixels - An Image’s Pixels - An Image’s AtomAtom
Pixels - An Image’s Pixels - An Image’s AtomAtom
Explore with DigitalImageBasicsExplore with DigitalImageBasics
What is a Digital What is a Digital Image?Image?
What is a Digital What is a Digital Image?Image?
Digital Images use numerical values of Digital Images use numerical values of
measured light intensitymeasured light intensity
Typically values “binned” between 0-255Typically values “binned” between 0-255
Red, Green, Blue (RGB)Red, Green, Blue (RGB)
Each set of measurements defines a Each set of measurements defines a
PicPicture ture ElElement or Pixelement or Pixel
Display of Light Intensity MeasurementsDisplay of Light Intensity Measurements
May alter what is displayedMay alter what is displayed
A A pixelpixel is the mixture is the mixture of red, green, & blue of red, green, & blue
intensities at a intensities at a location in the picturelocation in the picture
A A digital digital picturepicture is made is made of three fields of three fields
of color of color intensity intensity
measurementsmeasurements
Field of RED Field of RED IntensitiesIntensities
Field of Field of Green Green
IntensitiesIntensities
Field of Field of Blue Blue
IntensitiesIntensities
Digital Digital PicturePicture
Explore with DigitalImageBasicsExplore with DigitalImageBasics
Maps of the PolesMaps of the Poles
Spatial and Spectral Data
Spatial and Spectral Data
Colors, or spectral data, depend on
material properties
Boundaries of objects defined by change
in color from adjacent objects
Measure size based on boundaries
Length, Area, and Orientation
Explore with DigitalImageBasics
Colors, or spectral data, depend on
material properties
Boundaries of objects defined by change
in color from adjacent objects
Measure size based on boundaries
Length, Area, and Orientation
Explore with DigitalImageBasics
Open & Calibrate an Image
Open & Calibrate an Image
Almost any image may be used in software:
jpeg, gif, tiff, png, pdf, etc.
Calibration relates pixel size to
physical size of objects in image
Use longest known length in image
Test on scale of known length
Consider precision of measurements
Almost any image may be used in software:
jpeg, gif, tiff, png, pdf, etc.
Calibration relates pixel size to
physical size of objects in image
Use longest known length in image
Test on scale of known length
Consider precision of measurements
Exploring an ImageExploring an ImageOnly see ~0.75 megapixels on a computer
screen - use the zoom and pan features to see
all of the details (only 0.3 mp displayed)
Take the time to really look at the image
Look for patterns that make sense and those that
don’t
Also, what patterns are missing?
Make a story that makes ties your
observations together
Only see ~0.75 megapixels on a computer
screen - use the zoom and pan features to see
all of the details (only 0.3 mp displayed)
Take the time to really look at the image
Look for patterns that make sense and those that
don’t
Also, what patterns are missing?
Make a story that makes ties your
observations together
Spatial MeasurementsSpatial MeasurementsAll measurements include color analysis of
selected location
Fine tune location by clicking on small
arrows or click and drag circular points
Polygon may have up to 20 corners
Larger selected regions take more computer
processing
Additional data with color histogram tool
All measurements include color analysis of
selected location
Fine tune location by clicking on small
arrows or click and drag circular points
Polygon may have up to 20 corners
Larger selected regions take more computer
processing
Additional data with color histogram tool
Saving MeasurementsSaving MeasurementsSpatial and color measurements saved
Two additional inputs available
Additional data saved automatically:About image, about settings, about measurement
tool
Consider saving data to separate file for
each research question
May keep same settings when opening new
image (calibration, pan / zoom, mask /
enhancement, & spatial tool location)
Spatial and color measurements saved
Two additional inputs available
Additional data saved automatically:About image, about settings, about measurement
tool
Consider saving data to separate file for
each research question
May keep same settings when opening new
image (calibration, pan / zoom, mask /
enhancement, & spatial tool location)
The Electromagnetic SpectrumThe Electromagnetic Spectrum
Infrared Spectrum – 40 times broader than the Visible SpectrumInfrared Spectrum – 40 times broader than the Visible Spectrum
Beyond Our Eyes: IR & UV
Beyond Our Eyes: IR & UV
Reflection, Absorption Reflection, Absorption & Transmission& Transmission
Reflection, Absorption Reflection, Absorption & Transmission& Transmission
IncomingIncoming
ReflectedReflected
TransmittedTransmitted
AbsorbedAbsorbed
Reflectance & Land CoverReflectance & Land CoverReflectance & Land CoverReflectance & Land Cover
RGBRGB IRIR CombinedCombined
RGBRGB IRIR CombinedCombined
So what do these colors mean in this So what do these colors mean in this
Landsat image?Landsat image?So what do these colors mean in this So what do these colors mean in this
Landsat image?Landsat image?
BostonBoston
Near InfraredNear Infrared Red LightRed Light Green LightGreen Light
LANDSAT Color LANDSAT Color CompositeComposite
Landsat Color Landsat Color CompositeComposite
Near IR Near IR displayed as displayed as Red in ImageRed in Image
Red Light Red Light displayed as displayed as Green in ImageGreen in Image
Green Light Green Light displayed as displayed as Blue in ImageBlue in Image
Resulting Colors of Resulting Colors of Materials in ImageMaterials in Image
Healthy green Healthy green leaves look pink to leaves look pink to
redred
Pavement and dirt Pavement and dirt look cyan (or look cyan (or turquoise)turquoise)
Deep water is darkDeep water is dark
Sediment in water Sediment in water is lightis light
Monitoring Earth Using Monitoring Earth Using Satellite ImagerySatellite Imagery
Monitoring Earth Using Monitoring Earth Using Satellite ImagerySatellite Imagery
Since 1972, satellite imagery visible and near Since 1972, satellite imagery visible and near
infrared light have been used to determine:infrared light have been used to determine:
Type of land coverType of land cover Pavement, buildings, dirt, tree type, Pavement, buildings, dirt, tree type,
water, etc.water, etc.
Acreage of each land cover typeAcreage of each land cover type Health of vegetation coverHealth of vegetation cover
Study impact of seasonal change (natural), Study impact of seasonal change (natural),
drought, pests, air quality, & disease on drought, pests, air quality, & disease on
plantsplants
Since 1972, satellite imagery visible and near Since 1972, satellite imagery visible and near
infrared light have been used to determine:infrared light have been used to determine:
Type of land coverType of land cover Pavement, buildings, dirt, tree type, Pavement, buildings, dirt, tree type,
water, etc.water, etc.
Acreage of each land cover typeAcreage of each land cover type Health of vegetation coverHealth of vegetation cover
Study impact of seasonal change (natural), Study impact of seasonal change (natural),
drought, pests, air quality, & disease on drought, pests, air quality, & disease on
plantsplants
Enhancing ColorsEnhancing ColorsA change in color indicates a boundary or a
change in an object’s properties
Our eyes have limited sensitivity, so use a
computer to enhance small differences in
color:See new patterns
Identify a change in physical properties
Compare colors
Limit range of colors
Stretch range of colors
A change in color indicates a boundary or a
change in an object’s properties
Our eyes have limited sensitivity, so use a
computer to enhance small differences in
color:See new patterns
Identify a change in physical properties
Compare colors
Limit range of colors
Stretch range of colors
Masking ColorsMasking ColorsTurn colors within range or relationship to
black - all others will be white
Set a range to mask: click and drag on
histograms or drag a box on area of interest
Set relationship between colors to create a
mask
Beware: very slow to process!
Remember: the larger the image (more
pixels), the longer to process
Turn colors within range or relationship to
black - all others will be white
Set a range to mask: click and drag on
histograms or drag a box on area of interest
Set relationship between colors to create a
mask
Beware: very slow to process!
Remember: the larger the image (more
pixels), the longer to process
Combining ToolsCombining Tools
Use enhanced images with mask tools
Use enhanced & masked images with spatial
tools
Use color analysis with spatial tools in
creating enhanced or masked images
Combine strengths of each tool to measure
area of complex shapes
Only masked pixels (black) are counted when using
spatial tools
Use enhanced images with mask tools
Use enhanced & masked images with spatial
tools
Use color analysis with spatial tools in
creating enhanced or masked images
Combine strengths of each tool to measure
area of complex shapes
Only masked pixels (black) are counted when using
spatial tools
Getting Images from WebGetting Images from Web
Many ways to save image to your computer:
Open image on own webpage and “Save as”
Right click / control click on image
Take a screenshot of image
Save only copyright free images
Software works with colored maps and
graphs, photographs, satellite images,
etc.
Many ways to save image to your computer:
Open image on own webpage and “Save as”
Right click / control click on image
Take a screenshot of image
Save only copyright free images
Software works with colored maps and
graphs, photographs, satellite images,
etc.
