Copyright © 2003 Leica Geosystems GIS & Mapping, LLC Turning Imagery into Information Suzie Noble, Product Specialist Leica Geosystems Denver, CO

Introduction to Imagery IMAGERY

3 - Leica Geosystems GIS & Mapping, LLC Imagery basics - What is an Image? Image Type – Black and White (Panchromatic)

4 - Leica Geosystems GIS & Mapping, LLC Imagery basics Image Type – Natural color or Color infrared

5 - Leica Geosystems GIS & Mapping, LLC The value of the pixel Radiometric Resolution The specific wavelength intervals a sensor can record Spectral Resolution The Resolution of an image The area on the ground represented by a pixel Spatial Resolution

6 - Leica Geosystems GIS & Mapping, LLC Imagery basics – Spatial Resolution Spatial resolution is extremely Important! Determines what can be seen in an image Extremely Important! Determines what can be seen in an image Extremely Important! Determines what can be seen in an image

7 - Leica Geosystems GIS & Mapping, LLC Spatial Resolution Example 30 Meter Resolution 1 Pixel is 30m X 30m 1 Meter Resolution 1 Pixel is 1m X 1m

8 - Leica Geosystems GIS & Mapping, LLC Spatial Resolution & File Size Baseball Math Distance Between Bases = 90 ft. Total Infield Area = 8100 sq ft. An image with a 30m resolution = an Infield covered by 1 pixel An image with a 1m resolution = an Infield covered by 900 pixels Example of an image that covers 1 sq Mile 1,609 Pixels 1m Resolution 2,470 KB For each layer 53 Pixels 53 pixels 30m Resolution 2.74 KB For each layer

9 - Leica Geosystems GIS & Mapping, LLC Radiometric Resolution (8 bit data) A Pixel is One Data Byte A Byte is 8 Data Bits A Bit is either On or Off Combinations in a Byte Pixels Values Range from Black is 0 and White is 255 ON (2048 combinations for 11 bit data) (65,536 combinations for 16 bit data)

10 - Leica Geosystems GIS & Mapping, LLC Sensor Types There are two types of Imaging Satellites, Active and Passive. Active sensors (Radar) Emit their own energy Can be used day or night Can see through clouds and in arid climates can penetrate the surface of the earth Produce images that are comprised of a signal return Passive sensors Require an external energy source (e.g. the Sun). On a sun-synchronous orbit Altitude and look angles control revisit time Produce images of reflected light from various portions of the Electromagnetic Spectrum

11 - Leica Geosystems GIS & Mapping, LLC Multispectral Imagery Mid IR Allows Feature Delineation Beyond Visible Color Near IR Red Red Green Blue Blue Spectral Resolution

12 - Leica Geosystems GIS & Mapping, LLC Canada Centre for Remote Sensing Spectral Reflectance

13 - Leica Geosystems GIS & Mapping, LLC Ultraviolet Visible Near Infrared Mid Infrared Thermal -Scattered by the Atmosphere -Illuminates material in shadows not seen in longer wave lengths -Best water penetration for clear water -Contrast between clear and turbid water -Reflectance peak of vegetation in Visible region -Chlorophyll absorption band for vegetation discrimination -Carotene and xanthophylls reflectance (dead foliage) -Internal leaf tissue strongly reflective (decreases as stress increases) -Shoreline Mapping -Fire Fuels Modeling -Differentiation between evergreen and deciduous vegetation -Discrimination of oil on water -Moisture content of soil and vegetation -Limited cloud penetration -Contrast between vegetation types -Solar reflectance from metal buildings -Heat emissions from fires and smoke stacks -Smoke Penetration -Emitted and latent heat Spectral Range

14 - Leica Geosystems GIS & Mapping, LLC Viewing Bands of Data Thematic Mapper Band 1 Band 4 Band 5

15 - Leica Geosystems GIS & Mapping, LLC Viewing Images…Color Additive Process The computer monitor has 3 color guns: Red – Green – Blue (R, G, B) Red GreenBlue W YM C Landsat False Color Composite Band Combination (4,3,2) Healthy vegetation reflects highly in the Near Infrared (NIR) light. R4NIR G3Red B2Green

16 - Leica Geosystems GIS & Mapping, LLC BlueBandGreenBandRedBand Near IR Band Mid IR Band  True Color Provides a True Color Representation  Infrared Emphasizes Active Vegetation  SW Infrared Provides Vegetation Contrast and Sharp Shorelines Band Combinations

17 - Leica Geosystems GIS & Mapping, LLC Sources of Imagery

18 - Leica Geosystems GIS & Mapping, LLC QuickBird (Digital Globe) km IKONOS (Space Imaging) --11 km OrbView (Orbimage) 3--8 km Eros (ImageSat) 1A – 12.5 km Image Footprint Comparison

19 - Leica Geosystems GIS & Mapping, LLC LANDSAT Imagery Eight Image Bands Resolution: 30 m Multispectral 15 m Panchromatic 60 m Thermal Scene: 185 km x 170 km Revisit: 16 Day

20 - Leica Geosystems GIS & Mapping, LLC SPOT Imagery Five Image Bands Resolution: 20 m SWIR 10 m VG, VR, NIR 2.5 or 5 m Pan Scene: 60km x 60km Revisit: 4 Days

21 - Leica Geosystems GIS & Mapping, LLC OrbView Imagery OrbView-3 Four Image Bands Resolution: 4 m multispectral 1 m panchromatic Revisit: 3 Days Scene: 8 km swath User defined scenes

22 - Leica Geosystems GIS & Mapping, LLC IKONOS Imagery Four Image Bands Resolution: 1 m panchromatic –3.28 Feet 4 m multispectral –13.12 Feet Scene: 11 km swath –6.8 miles 100 km max. length –62 miles User Defined Scenes Apx 3-day revisit

23 - Leica Geosystems GIS & Mapping, LLC QuickBird Imagery Four Image Bands Resolution: 61 cm panchromatic –2.00 Feet 2.4 m multispectral –7.87 Feet Scene: 16.5 km swath –10 miles 165 km max. length –102 miles User Defined Scenes Apx 3-day revisit

Shadows of People on the Sidewalk Individual Trees Distinguishing Cars and Trucks Taken from 279 miles above Earth (Digital Globe – Quickbird 3 pan/multi merge)

25 - Leica Geosystems GIS & Mapping, LLC Digital Orthophoto Quadrangle Geometrically correct aerial photo Ideal for extracting Ground Control Points Available for downloading

26 - Leica Geosystems GIS & Mapping, LLC Digital Raster Graphics (Maps) Scanned USGS Topo Quads Similar to imagery for processing Ideal for extracting Ground Control Points Available for downloading for a small fee

27 - Leica Geosystems GIS & Mapping, LLC Digital Elevation Models USGS 30 meter available for entire country USGS 10 meter partial coverage Download for free

28 - Leica Geosystems GIS & Mapping, LLC Aerial Photography Sensor Properties  Multiple collection scenarios  Varying Scales Use  ROW Management  Environmental monitoring  Facilities management  Agricultural monitoring  Vegetation health  Urban planning  Stormwater management  LULC