Remote Sensing Image Acquisition Supplement to Lecture 1 material prepared by R. Lathrop 9/99 updated 8/03 includes slides previously prepared by S. Madry and C. Colvard Readings: ERDAS Field Guide 5th Ed. Ch 1, 3:56-82

Digital Image Acquisition Digitization of analog aerial photography, can be very useful for historical studies and/or for high spatial resolution needs Direct acquisition using some form of digital imaging sensor

Early attempts Kite system acquired aerial photos of the great San Francisco earthquake and fire Pigeon cameras The development of aircraft World Wars I and II

Aerial Cameras Keystone’s Wild RC-10 mapping camera A large format oblique camera

Aerial photos Black & White - single panchromatic layer Color: 3 layers B-G-R Color IR: 3 layers G-R-NIR

USGS Aerial Photo Products Aerial Products Description National Aerial Photography Program (NAPP) Recent,high-quality aerial photos covering the conterminous U.S. on five- to seven-year cycles (1987 - present). National High Altitude Photography (NHAP) High-altitude aerial photos for the conterminous U.S. (1980 - 1989). Digital Orthophoto Quadrangles (DOQs)  Digital images of aerial photos which combine the image characteristics of the photo with the georeferenced qualities of a map (1987 - present). Space Acquired Photography  Photos taken from the International Space Station (ISS), Shuttle, Skylab, Gemini, and Apollo missions (1965 - present). For more info: http://edc.usgs.gov/products/aerial.html

Analog Image Digitization Scanning micro-densitometer Linear array charge-coupled device e.g., flat-bed scanners Area array charge-coupled device e.g., digital camera

Remote Sensing Systems - Instrumentation Radiometer - electro-optical instrument measuring radiant flux (energy) Spectroradiometer - instrument that measures radiant flux as a function of wavelength - often as a continuous spectra Multispectral scanner - imaging spectro-radiometer measuring radiant flux in specific spectral wavebands

Major Elements of electro-optical scanners Optical system: lenses, mirrors, apertures, modulators & dispersion devices Detectors: provide an electrical signal proportional to the irradiance on its active surface, generally some type of semiconductors Signal Processor: performing specified functions on the electrical signal to provide the desired output data

Electro-optical scanners Elements sensitive to electro magnetic energy (EME) of certain wavelengths focus energy onto a sensor plane. A prism is used to divide the energy into specific wavelengths. The CCD’s are stimulated and produce an electrical signal equal to the energy focused upon it. These data are recorded. Data are converted from an analog electrical signal to a digital number

3 different scanner designs Single detector CCD-Scan Mirror TM Pushbroom scanner SPOT Two dimensional Staring Array Space Imaging Original Current Future

Important imaging parameters The Instantaneous Field of View (IFOV) subtends an area on the terrain called a Ground Resolution Cell (GRC) The Angular Field of View determines the width of the Ground Swath The Dwell Time, the time required for the detector IFOV to sweep across the GRC

Airborne Remote Sensing Aircraft Scanners Digital imagery acquired from several multispectral scanners on board NASA ER-2, NASA C-130B, and NASA Learjet aircrafts (1982 - 1995). For more info: http://edcdaac.usgs.gov/airborne/air_scan.html Digital Cameras increasingly aerial imagery is being acquired through digital camera framing systems that can collect multispectral (VIS-NIR) imagery and be quickly corrected through GPS-based navigational systems to produce digital orthophotographic imagery in near-real time

Remote Sensing Satellites in Space: How do they get there? http://visibleearth.nasa.gov/cgi-bin/viewrecord?492

MODIS Terra Launches http://visibleearth.nasa.gov/cgi-bin/viewrecord?135

Types of satellite orbits Geostationary Polar 700-900 km 35,800 km

Polar Orbitting Satellite http://visibleearth.nasa.gov/cgi-bin/viewrecord?134

Geostationary vs. polar orbiting sensors Geostationary sensors orbit with the earth continually viewing the same hemispheric area Polar orbiters, continually view new areas of the earth as the planet rotates underneath the sensor. Keeps the same general solar time as it cross the equator on each orbit - called sun synchronous Polar orbit

Many different systems - which to choose?

AVHRR-Advanced Very High Resolution Radiometer Polar orbit, coarse spatial resolution: 1 and 4 km cells, broad 2400 km ground swath width 2 operational now-1 day and 1 night pass for each

AVHRR Thermal AVHRR provides water temperature data 3 bands in TIR Gulf Stream

Remote Sensing of the Earth: Clues to a Living Planet Scientists at the NASA Goddard Space Flight Center have used the AVHRR to create maps of vegetation greenness for the entire globe The NASA scientists have combined numbers of satellite images to create a composite picture of the earth at approximately biweekly intervals over a number of years For more info and images, go to: http://daac.gsfc.nasa.gov/CAMPAIGN_DOCS/BRS_SRVR/avhrrbrs_main.html

Global AVHRR composite 1 band in the Red: .58-.6 um 1 band in the NIR: .72-1.1 um Vegetation Index to map vegetation amount and productivity

Remote Sensing of the Earth: Clues to a Living Planet You can access these images over the INTERNET http://daac.gsfc.nasa.gov/CAMPAIGN_DOCS/LAND_BIO/GLBDST_Images.html You can either browse through individual images or watch an animation First, click on the Global 1 degree 1986 NDVI (Climate Data Set) (1.5 MB Quicktime) animation. Open it, and click on the > button. You can go more slowly by clicking on the |> button.

Remote Sensing of the Earth: Clues to a Living Planet First, click on the Global 1 degree 1986 NDVI (Climate Data Set) (1.5 MB Quicktime) animation. Open it, and click on the > button. Watch closely, can you observe the Green Wave in the northern hemisphere? What about the Brown Wave? Now look at the southern hemisphere. What do you observe?

Can you see the Green Wave? http://daac.gsfc.nasa.gov/CAMPAIGN_DOCS/LAND_BIO/GLBDST_Images.html

Remote Sensing of the Earth: Clues to a Living Planet Now take a look at the Northern hemisphere in greater detail. Click on the North America 1986 NDVI (750K quicktime) Animation. Can you find where you live? How long does it stay green? Compare Florida with Maine or Minnesota.

North America: Close-up http://daac.gsfc.nasa.gov/CAMPAIGN_DOCS/LAND_BIO/GLBDST_Images.html

Remote Sensing of the Earth: Clues to a Living Planet To access more recently acquired AVHRR imagery go to the National Oceanographic & Atmospheric Administration (NOAA) Satellite Active Archive http://www.saa.noaa.gov/

After a picture-perfect launch into space December 1999, Terra Began releasing images April 2000. Terra includes MODIS, a 2nd generation “AVHRR-like” instrument, with a number of potential applications in regional to global scale environmental monitoring of the land, ocean and atmosphere. Also includes ASTER, CERES, MISR and MOPITT. For more info go to: http://terra.nasa.gov/

MODIS TERRA in Orbit http://visibleearth.nasa.gov/cgi-bin/viewrecord?133

36 discrete bands between 0.4 and 14.5 µm spatial resolutions of 250, 500, or 1,000 m at nadir. Signal-to-noise ratios are greater than 500 at 1-km resolution (at a solar zenith angle of 70°), and absolute irradiance accuracies are < ±5% from 0.4 to 3 µm (2% relative to the sun) and 1 percent or better in the thermal infrared (3.7 to 14.5 µm). MODIS instruments will provide daylight reflection and day/night emission spectral imaging of any point on the Earth at least every 2 days, operating continuously. For more info: http://eospso.gsfc.nasa.gov/eos_homepage/mission_profiles/instruments/MODIS.php

3 visible/NIR(VNIR: 0.5 and 0.9 µm) with 15-m resolution 3 mid IR (SWIR: 1.6 and 2.43 µm) with 30-m res. 5 TIR (8 and 12 µm) with 90-m resolution 60- km swath whose center is pointable cross-track ±8.55° in the SWIR and TIR, with the VNIR pointable out to ±24°. An additional VNIR telescope (aft pointing) covers the wavelength range of Channel 3. By combining these data with those for Channel 3, stereo views can be created, with a base-to-height ratio of 0.6. Overpass every 16 days in all 14 bands and once every 5 days in the three VNIR channels. For more info: http://eospso.gsfc.nasa.gov/eos_homepage/mission_profiles/instruments/ASTER.php

“Aqua,” Latin for “water,” is a NASA Earth Science satellite mission named for the large amount of information that the mission will be collecting about the Earth’s water cycle, including evaporation from the oceans, water vapor in the atmosphere, clouds, precipitation, soil moisture, sea ice, land ice, and snow cover on the land and ice. Additional variables also being measured by Aqua include radiative energy fluxes, aerosols, vegetation cover on the land, phytoplankton and dissolved organic matter in the oceans, and air, land, and water temperatures. The AQUA Platform includes the MODIS, CERES and AMSR_E instruments. Aqua was formerly named EOS PM, signifying its afternoon equatorial crossing time. AQUA was launched May 2002. For more info: http://aqua.nasa.gov/

ERTS-1 Earth Resources Technology Satellite-1 Renamed Landsat Multispectral scanner (MSS) First images in late 1972 Was the first civil remote sensing satellite

Landsat MSS bands 4 and 5 GREEN RED

Landsat MSS bands 6 and 7 INFRARED 1 INFRARED 2 Note: water absorbs IR energy-no return=black INFRARED 1 INFRARED 2

MSS color composite combining bands creates a false color composite Manhattan Rutgers combining bands creates a false color composite red=vegetation light blue=urban black=water pink=agriculture Philadelphia Pine barrens Chesapeake Bay Delaware River

Landsat 4-5 Thematic Mapper (TM)

Cross-track scanning system

Landsat TM-7 bands-8 bit data Spectral (where we look) Radiometric (how finely can we measure the return) 0-63, 0-255, 0-1023 Landsat TM BAND 1 2 3 4 5 7 6

Spectral wavebands of Landsat TM

Landsat TM: each waveband provides different information about earth surface features

Thermal imagery-temperature Water analysis-nuclear power cooling ponds)

Commercialization of Landsat Landsat was commercialized by Pres. Reagan EOSAT formed sales dropped

Landsat 7 15 m ETM+ (enhanced TM) sensor April 1999 launch Oct.’92 Land remote sensing policy act a panchromatic band with 15m spatial resolution-fully coregistered w/30m on-board, full aperture, 5% absolute radiometric calibration a thermal IR channel with 60m spatial resolution for more info go to: http://landsat.gsfc.nasa.gov/

Will have 2.5 m in 1999 French commercial remote sensing system First launch in 1986 10 and 20 m spatial resolution 60 km swath width Stereo viewing ability Will have 2.5 m in 1999

Panchromatic (PAN) sensor: 10 m GRC Pan 0.51-.73 um High Resolution Visible (HRV) sensor: 20m GRC G (.5-.59), R (.61-.68), NIR (.79-.89) Ground Swath Width of 60 km For more info go to: http://www.spotimage.fr/home/home.htm

SPOT before launch

SPOT ground stations

SPOT 4 1st images taken March 31, 1998

Polar Sun synchronous orbit 2 side-by-side HRV sensors

SPOT has steerable mirror

Stereo imaging

Indian Remote Sensing (IRS) satellite IRS-1C launched in December 1995 IRS1D launched in September 1997 Panchromatic: 0.5-0.75 um 5.8 m GRC, 30 km ground swath 22 day repeat cycle with off-nadir pointability

Space Imaging IKONOS Panchromatic (045-0.9 um): 1 m Multispectral: 4 m Blue (445-516nm), Green(506-595nm) Red (632-698nm) NIR (757-853nm) 11 km swath width Pointable to 45o for daily viewing For more info go to: http://www.spaceimage.com/index.htm

IKONOS SAMPLE IMAGERY Multi-spectral 4m GRC Pan-chromatic 1m GRC

Space Imaging IKONOS Imagery Sample: Bound Brook NJ 1 m panchromatic 4 m multi-spectral

OrbView-3 Panchromatic: 1 m Multispectral (color): 4 m Pointable: anywhere on globe within 3 days Additional hyperspectral sensor For more info go to: http://www.orbimage.com/index.html

Quickbird DigitalGlobe™ successfully launched its QuickBird satellite on the Boeing Delta II launch vehicle on October 18, 2001. Panchromatic: 0.61-1m Multispectral (color): 2.5-4 m Can increase the resolution system by adjusting the orbit in which the satellite is flown. As a result, panchromatic resolution increases from 1 meter to 61 centimeters and multi-spectral increases from 4- to 2.5-meter resolution. The satellite will operate in a 450-km 98-degree sun-synchronous orbit, with each orbit taking 93.4 minutes http://www.digitalglobe.com/index.shtml

Different sensors and resolutions sensor spatial spectral radiometric temporal ---------------------------------------------------------------------------------------------------------------- AVHRR 1.1 and 4 KM 4 or 5 bands 10 bit 12 hours 2400 Km .58-.68, .725-1.1, 3.55-3.93 (0-1023) (1 day, 1 night) 10.3-11.3, 11.5-12.5 (micrometers) Landsat MSS 80 meters 4 bands 6 bit 16 days 185 Km .5-.6, .6-.7, .7-.8, .8-1.1 (0-63) Landsat TM 30 meters 7 bands 8 bit 14 days 185 Km .45-.52, .52-.6, .63-.69, (0-255) .76-.9, 1.55-1.75, 10.4-12.5, 2.08-2.3 um SPOT P 10 meters 1 band 8 bit 26 days 60 Km .51-.73 um (0-255) (2 out of 5) SPOT X 20 meters 3 bands 8 bit 26 days 60 Km .5-.59, .61-.68, .79-.89 um (0-255) (2 out of 5) IKONOS 1 and 4 meters 1 and 4 bands 10 bit 1-2 days 11 km .45-.9, .44-.51, .52-.60, (0-1023) .63-.70, .76-.85

Homework 1: Selecting and Ordering Imagery 1. Enhanced Landsat Thematic Mapper 7 (ETM+) imagery is available through the U.S. Geological Survey. Go to the USGS’ Earth Explorer web site (http://edcsns17.cr.usgs.gov/EarthExplorer/) or their newer, better web browser (http://glovis.usgs.gov). A. How many Landsat TM scenes are needed to image the entire state of New Jersey? B. What are the Path/Row numbers? C. What is the cost per square km for the ETM+ Level 1G image? Hint: 1st determine the area of the scene in km2, then divide scene cost by area D. Using the Search Archive capabilities, determine the date of the most recent cloud-free (<20%) ETM+ image for Middlesex County, NJ. What is the Scene ID, Path/Row and date?

Homework 1: Selecting and Ordering Imagery 2. The OrbImage Corporation (www.orbimage.com/) markets OrbView and other high resolution imagery. Access the OrbImage site to get up-to-date information on pricing and availability. A. What is the spatial accuracy and cost per square kilometer for the standard OrbView Cities product? OrbView Cities Plus? 3. DigitalGlobe (www.digitalglobe.com) markets Quickbird imagery. Access the DigitalGlobe site to get up-to-date information on pricing and availability? A. What types of Quickbird image products are offered?

Good Bye from Planet Earth Source http://visibleearth.nasa.gov/