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Studying Polar Change with Digital Images John Pickle Concord Academy, Concord, MA John Pickle Concord.

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Presentation on theme: "Studying Polar Change with Digital Images John Pickle Concord Academy, Concord, MA John Pickle Concord."— Presentation transcript:

1 Studying Polar Change with Digital Images John Pickle Concord Academy, Concord, MA John Pickle Concord Academy, Concord, MA

2 AgendaAgenda Overview of Goals & Activities Overview of Goals & Activities Basics of Color, Digital Images, & Maps Basics of Color, Digital Images, & Maps Spatial Measurements Spatial Measurements Enhancing Colors to See Patterns Enhancing Colors to See Patterns Masking Colors to Isolate Patterns Masking Colors to Isolate Patterns Putting it all together to study change Putting it all together to study change Overview of Goals & Activities Overview of Goals & Activities Basics of Color, Digital Images, & Maps Basics of Color, Digital Images, & Maps Spatial Measurements Spatial Measurements Enhancing Colors to See Patterns Enhancing Colors to See Patterns Masking Colors to Isolate Patterns Masking Colors to Isolate Patterns Putting it all together to study change Putting it all together to study change

3 Goals of Activities Maps and images are spatial representation of data Maps and images are spatial representation of data Software allows rapid & efficient access to the data Software allows rapid & efficient access to the data Emphasize big ideas & flexible application Emphasize big ideas & flexible application Maps and images are spatial representation of data Maps and images are spatial representation of data Software allows rapid & efficient access to the data Software allows rapid & efficient access to the data Emphasize big ideas & flexible application Emphasize big ideas & flexible application

4 Color - Light vs Paint Mixing all of your paints in your paint set produced what color? Mixing all of your paints in your paint set produced what color? Putting white light through a prism produces what? Putting white light through a prism produces what? Explore subtractive and additive colors using ColorBasics software Explore subtractive and additive colors using ColorBasics software Mixing all of your paints in your paint set produced what color? Mixing all of your paints in your paint set produced what color? Putting white light through a prism produces what? Putting white light through a prism produces what? Explore subtractive and additive colors using ColorBasics software Explore subtractive and additive colors using ColorBasics software

5 Color Red Value Green Value Blue Value Black0%0%0% White100%100%100% Red100%0%0% Yellow100%100%0% Green0%100%0% Cyan0%100%100% Blue0%0%100% Magenta100%0%100% Orange100%50%0% Purple50%0%70% Brown70%40%15% Pink100%80%80% Light Gray 75%75%75% Medium Gray 50%50%50% Dark Gray 25%25%25%

6 Red 62% Green 71% Blue 11% Red 51% Green 41% Blue 35% Red 12% Green 11% Blue 11% Pixels - An Images Atom Explore with DigitalImageBasics

7 What is a Digital Image? Digital Images use numerical values of measured light intensity Digital Images use numerical values of measured light intensity Typically values binned between Typically values binned between Red, Green, Blue (RGB) Red, Green, Blue (RGB) Each set of measurements defines a Picture Element or Pixel Each set of measurements defines a Picture Element or Pixel Display of Light Intensity Measurements Display of Light Intensity Measurements May alter what is displayed May alter what is displayed

8 A pixel is the mixture of red, green, & blue intensities at a location in the picture A digital picture is made of three fields of color intensity measurements Field of RED Intensities Field of Green Intensities Field of Blue Intensities Digital Picture Explore with DigitalImageBasics

9 Maps of the Poles

10 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

11 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

12 Exploring an Image 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 dont 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 dont Also, what patterns are missing? Make a story that makes ties your observations together

13 Spatial Measurements 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 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

14 Saving Measurements 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) 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)

15 The Electromagnetic Spectrum

16 Infrared Spectrum – 40 times broader than the Visible Spectrum Beyond Our Eyes: IR & UV

17 Reflection, Absorption & Transmission Incoming Reflected Transmitted Absorbed

18 Reflectance & Land Cover RGBIR Combined

19 So what do these colors mean in this Landsat image? So what do these colors mean in this Landsat image? Boston

20 Near Infrared Red Light Green Light LANDSAT Color Composite Landsat Color Composite Near IR displayed as Red in Image Red Light displayed as Green in Image Green Light displayed as Blue in Image Resulting Colors of Materials in Image Healthy green leaves look pink to red Pavement and dirt look cyan (or turquoise) Deep water is dark Sediment in water is light

21 Monitoring Earth Using Satellite Imagery Since 1972, satellite imagery visible and near infrared light have been used to determine: Since 1972, satellite imagery visible and near infrared light have been used to determine: Type of land cover Type of land cover Pavement, buildings, dirt, tree type, water, etc. Pavement, buildings, dirt, tree type, water, etc. Acreage of each land cover type Acreage of each land cover type Health of vegetation cover Health of vegetation cover Study impact of seasonal change (natural), drought, pests, air quality, & disease on plants Study impact of seasonal change (natural), drought, pests, air quality, & disease on plants Since 1972, satellite imagery visible and near infrared light have been used to determine: Since 1972, satellite imagery visible and near infrared light have been used to determine: Type of land cover Type of land cover Pavement, buildings, dirt, tree type, water, etc. Pavement, buildings, dirt, tree type, water, etc. Acreage of each land cover type Acreage of each land cover type Health of vegetation cover Health of vegetation cover Study impact of seasonal change (natural), drought, pests, air quality, & disease on plants Study impact of seasonal change (natural), drought, pests, air quality, & disease on plants

22 Enhancing Colors A change in color indicates a boundary or a change in an objects 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 objects 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

23 Masking Colors 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 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

24 Combining 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

25 Getting 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.


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