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

A large format oblique camera

Keystone’s Wild RC-10 mapping camera

Aerial photos• Black & White -

single panchromatic layer

• Color: 3 layers B-G-R

• Color IR: 3 layers G-R-NIR

USGS Aerial Photo ProductsAerial 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

Aerial Photographic Sources• USDA: (since 1955): mainly PAN of

1:20,000-1:40,000. These photos are archived by the Aerial Photography Field Office http://www.fsa.usda.gov/dam/APFO/airfto.htm

• National Archives and Records Administration archives older (pre- 1950’s) aerial photography http://www.nara.gov/research/ordering/mapordr.html

Aerial Photographic Sources• National Ocean Survey (NOS) coastal photography:

(since 1945), color, scales of 1;10,000 - 1:50,000• The photos are used for a variety of geo-positioning

applications, which include delineating the shoreline for Nautical Chart creation, measuring water depths, mapping seabed characteristics, and locating obstructions to marine and air navigation.

• http://mapfinder.nos.noaa.gov

Analog Image Digitization

• Can take analog photography and turn into digital images

• Scanning micro-densitometer

• Linear array charge-coupled device e.g., flat-bed scanners

• Area array charge-coupled device e.g., digital camera

Airborne Digital Imaging Systems

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

Space-borne Remote Sensing

Still Emerging TechnologyPro:•GIS ready•fast turn around•acquisition time of 5 minutes gives equal solar illumination, shadows•long term archive of repeat imagery for change detectionCon:•Significant investment in infrastructure•Less flexibility in acquisition

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

35,800 km

700-900 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 underneaththe 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, TerraBegan 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

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/

“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.

ENVISAT

• In March 2002, the European Space Agency launched Envisat, an advanced polar-orbiting Earth observation satellite which provides measurements of the atmosphere, ocean, land, and ice.

• http://envisat.esa.int/

ENVISAT: primary instruments for land/sea surface remote sensing

• ASAR - Advanced Synthetic Aperture Radar, operating at C-band,

• MERIS - is a 68.5 o field-of-view pushbroom imaging spectrometer that measures the solar radiation reflected by the Earth, at a ground spatial resolution of 300m, in 15 spectral bands, programmable in width and position, in the visible and near infra-red. MERIS allows global coverage of the Earth in 3 days.

http://envisat.esa.int/

SPOT Vegetation

• Earth observation sensor on board of the SPOT satellite in blue, red, NIR & SWIR

• Daily coverage of the entire earth at a spatial resolution of 1 km

• The first VEGETATION instrument is part of the SPOT 4 satellite and a second payload, VEGETATION 2, is now operationally operated onboard SPOT 5.

• http://www.spot-vegetation.com/

SPOT Vegetation Spectral Bands

SPOT Vegetation• Free products are :• extracts from ten day global syntheses. • available 3 months after insertion in the

VEGETATION archive. • in full resolution (1km). • in plate carrée projection. • available on 10 predefined regions of interest. • in the standard VEGETATION product format. • http://free.vgt.vito.be/

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 2INFRARED 1

Note: water absorbs IR energy-no return=black

• combining bands creates a false color composite

• red=vegetation• light blue=urban• black=water

• pink=agriculture

Rutgers

Manhattan

PhiladelphiaPine barrensChesapeake BayDelaware River

MSS color composite

Landsat 4-5 Thematic Mapper (TM)

Cross-track scanning system

Landsat TM-7 bands-8 bit dataSpectral

(where we look)

Radiometric(how finely can wemeasure 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)

Blew up at launch

http://www.earth.nasa.gov/history/landsat/landsat.html

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/

On May 31 2003, the Landsat 7 ETM sensor had a malfunction and the Scan Line Corrector failed which means there are gaps in data collection that are especially exacerbated towards the edge of the imagery. •All Landsat 7 ETM+ scenes acquired after July 14, 2003 were collected in Scan Line Corrector-off mode. •Landsat 7 ETM+ scenes acquired from 5/31/03 - 7/14/03 and 9/3/03 - 9/17/03 are not available

Source: US Geological Survey http://landsat.usgs.gov/slc_off.html

Source: U.S. Geological Survey

SLC-off SLC-on

Landsat 7 ETM with SLC-off

Earth Observing 1• NASA’s New Millennium Program

• Multispectral instrument that is a significant improvement over the Landsat 7 ETM+ instrument – Advanced Line Imager (ALI)

• Hyperspectral land imaging instrument – Hyperion

• Low-spatial/high-spectral resolution imager that can correct systematic errors in the apparent surface reflectances caused by atmospheric effects, primarily water vapor - Linear Etalon Imaging Spectrometer Array (LEISA) Atmospheric Corrector (LAC)

EO-1: Advanced Line Imager (ALI)

• The EO-1 ALI operates in a pushbroom fashion at an orbit of 705 km, 16 day repeat cycle. Launched in Nov 2000.

• ALI provides Landsat type panchromatic and multispectral bands. These bands have been designed to mimic six Landsat bands with three additional bands covering 0.433-0.453, 0.845-0.890, and 1.20-1.30 µm.

• The ALI has 30M resolution multi-spectral 10m panchromatic. 37km swath width.

• More info: http://eo1.usgs.gov/ali.php

Mt. Fuji Japan ALI Bands: 6,5,4.

EO-1: Hyperion• The Hyperion collects 220 unique spectral

channels ranging from 0.357 to 2.576 micrometers with a 10-nm bandwidth.

• The instrument operates in a pushbroom fashion, with a spatial resolution of 30 meters for all bands.

• The standard scene width is 7.7 kilometers. Standard scene length is 42 kilometers, with an optional increased scene length of 185 kilometers

• More info: http://eo1.usgs.gov/hyperion.php

Mt. Fuji, Japan. Hyperion bands 215, 54, 15

EO-1• ALI & Hyperion designed to work in tandem

• 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/after launch

SPOT ground stations

SPOT 41st 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

http://www.nrsa.gov.in/engnrsa/satellites/satellites.html

IRS RESOURCESAT-1• RESOURCESAT-1 launched into its 817 km orbit on Oct. 17, 2003 • A high-resolution Linear Imaging Self Scanner (LISS-4) operating

in three spectral bands in the visible and near-infrared region with 5.8-meter resolution and steerable up to ± 26 degrees across track to obtain stereoscopic imagery and achieve five-day revisit capability.

• A medium-resolution LISS-3 sensor operating in four spectral bands in visible, near-infrared and short wave infrared with 23-meter resolution.

• An Advanced Wide Field Sensor (AWiFS) operating in four spectral bands in visible, near-infrared and one short wave infrared with 56-meter resolution. * In addition, RESOURCESAT-1 has a solid-state recorder with a capacity of 120 gigabits to store the images taken by its cameras.

Formosat-2• The Taiwanese FORMOSAT-2 satellite developed for the NSPO

(National SPace Organization) was successfully launched on 20 May 2004.

• FORMOSAT-2’s can acquire any scene in its coverage area each day (due to its geosynchronous orbit) with off-nadir capability (up to +/- 45°) both along track (forward and backward looking) and across track (side looking).

• black and white images with 2-m resolution, • color images with 8-m resolution (4 spectral bands: near infrared,

red, green and blue), • each scene covers 24 km x 24 km. • Distributed by SpotImage

http://www.spotimage.fr/html/_167_171_673_.php

Space Imaging IKONOS

• Panchromatic (045-0.9 um): 1 m

• Multispectral: 4 mBlue (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

4 m multi-spectral

1 m panchromatic

Space Imaging IKONOS Imagery Sample: Bound Brook NJ

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

Wishful thinking!

OrbView4 did not achieve orbit on launch on Sept 21, 2001

OrbView 5: upping the ante

• Scheduled for launch in early 2007, OrbView-5 will simultaneously acquiring 0.41-meter panchromatic and 1.64-meter multispectral (B-G-R-NIR) imagery.

• Swath width: 15.2 km• 11 bits per pixel• Revisit Time: <3 days• http://www.orbimage.com/corp/orbimage_system/ov5/

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 umSPOT 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

• For a recent review of land imaging satellites refer to the Guide to Land Imaging Satellites online at ASPRS

http://www.asprs.org/news/satellites/

Sources for downloadable imagery

• Download Landsat, ASTER, MODIS, Quickbird, SRTM, http://glcf.umiacs.umd.edu/data/

• NASA Stennis Space Center Download Landsat 1990/2000 imagery as Mr. Sid format https://zulu.ssc.nasa.gov/mrsid/

• NASA Worldwind 1.3 Visualization software that includes Landsat 7, MODIS, SRTM

http://worldwind.arc.nasa.gov/

Homework 1: Selecting and Ordering Imagery1. 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 areaD. 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?

Source http://visibleearth.nasa.gov/

Good Bye from Planet Earth