Introduction To Rs

Tools of the trade Introduction to Remote Sensing

Remote Sensing • General definition • Applied definition

Remote Sensing • Formal definition – Acquisition and measurement of data on property(ies) of a phenomenon by recording device not in physical contact with feature(s)

• RS techniques – Measure force fields, EM radiation, or acoustic energy – Use cameras, radiometers, scanners, lasers, radios, radar systems, sonar, thermal devices, seismographs, magnetometers, gravimeters and other instruments

The Remote Sensing System Se

or s n

The Remote Sensing System • • • • • • • •

Energy source Transmission through atmosphere Interaction with target Retransmission through atmosphere Recording of energy by sensor Data download Interpretation and analysis Application

History of Remote Sensing • The beginning of RS – Technology started with photography in early 19th century – Balloons used for aerial photos in 1840s – Photographic camera most common sensor for > 150 years

• Higher altitude image acquisitions – 1940’s  rocket launched cameras: still or movie collection – The first non-film sensors on unmanned spacecraft used to observe clouds

History of Remote Sensing (cont’d) • Transition to humans in space

Modern Space Remote Sensing

• Modern RS

– Satellites designed for capture of earth resource information – Landsat Multispectral Scanner System launched in 1972

• Characteristics of MSS – Consistent, synoptic, high resolution images of earth – 4 spectral bands, 80m spatial resolution, large coverage area (185 × 185 km) – Repeated coverage every 18 days – Digitally formatted imagery

Modern Space Remote Sensing cont. • Since 1972 – Many satellites and sensors launched – Sponsored by various governments and commercial sector – Additional sensors available using airborne platform

• Types of sensors extended – Multispectral e.g. MSS, TM, ETM+, SPOT – Hyperspectral e.g. AVIRIS, HYDICE – High spatial resolution e.g. IKONOS, QuickBird, Emerge – Low spatial resolution e.g. AVHRR, GOES

Applications of Remote Sensing • Atmosphere and meteorology • Global change detection and monitoring • Military • Mapping

Applications of Remote Sensing • Environmental assessment and monitoring • Agriculture • Renewable natural resources

Stages in Applying RS • Define issue • Consider issues with RS system • Assessing the end product

Photographic Film Types • Black and white • Color • Controlling information recorded

Black and White Film Structure Film cross-section Emulsion Polyester base Backing

Black and White Film Sensitivity Spectral Sensitivity

Panchromatic B/W infrared

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Wavelength (µm)

Human Vision System • Aperture • Light detection in eye – Rods – Cones

Color Film Structure Film cross-section Blue sensitive Green sensitive Red sensitive Polyester base Backing

Yellow filter

Normal Color Film Sensitivity Blue sensitive dye (yellow forming)

Green sensitive dye ( Magenta forming)

Spectral Sensitivity

Red sensitive dye (Cyan forming)

0.3

0.4

0.5

0.6

0.7

Wavelength (µm)

Color IR Film Sensitivity Yellow forming Magenta forming

Spectral Sensitivity

Cyan forming

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Wavelength (µm)

Filters • Purpose of filters • Common filters • Challenge with filtering

Aerial Film Cameras • Handheld cameras – 35 mm (24 × 36 mm frame) – 70 mm (55 × 55 mm frame)

• Purpose built aerial cameras

• Types of aerial cameras

Single-Lens Frame Cameras • Application

• Characteristics of mapping cameras

Single-Lens Frame Cameras • Focal length

• Angular field of view

Single-Lens Frame Camera Components • Lens assembly

• Body • Magazine

Single-Lens Frame Camera • Film exposure

Panoramic Cameras • Approach

• Distortions • Compared to frame cameras

History of Landsat • Early satellites designed for weather applications • Partnership in Earth Resources Technology Satellites • Planned satellite names – Pre-launch ERTS-A, -B, -C, -D, -E, -F – After-launch ERTS-1, -2, -3, -4, -5, -6

History of Landsat • First launch ERTS-1 23 July 1972: renamed Landsat-1 in 1975

• First satellite for earth resource observation • Intent

Satellite

Launch

Decomm.

Sensors

Orbit

Landsat-1

1972

1978

RBV, MSS

18 days/900 km

Landsat-2

1975

1982

RBV, MSS

18 days/900 km

Landsat-3

1978

1983

RBV, MSS

18 days/900 km

Landsat-4

1982

1993*

MSS, TM

16 days/705 km

Landsat-5

1984

MSS, TM

16 days/705 km

Landsat-6

1993

Failed

ETM

16 days/705 km

Landsat-7

1999

2003*

ETM+

16 days/705 km

* Partial system failure

Spectral Resolution: RBV 0. 4

1. 3

0. 7

Visible

Near-IR

3. 0

Mid-IR

Thermal-IR Wavelength (µm)

Pan (30 m)

A-D*

Multi 1° 2° (80 m)

3°

° Onboard Landsat-1, -2 * Onboard Landsat-3

Spectral Resolution: MSS 0. 4

1. 3

0. 7

Visible

Near-IR

3. 0

Mid-IR

Thermal-IR Wavelength (µm)

4° 5° 6° Multi (79°/82* m) 1* 2* 3*

Thermal (240 m)

7° 4*

8# ° Onboard Landsat-1, -2, -3 #

Onboard Landsat-3 – failed after launch

* Onboard Landsat-4, -5

Spectral Resolution: TM 0. 4

1. 3

0. 7

Visible

3. 0

Near-IR

Mid-IR

Thermal-IR Wavelength (µm)

Multi 1 2 (30 m)

3

4

5

Thermal (120 m)

7

6

Onboard Landsat-4, -5

Spectral Resolution: ETM+ 0. 4

1. 3

0. 7

Visible

3. 0

Near-IR

Mid-IR

Thermal-IR Wavelength (µm)

Pan (15 m)

8

Multi 1 2 (30 m)

3

4

5

Thermal (60 m)

7

6 Onboard Landsat-6*, -7

Landsat-1, -2, -3 • Satellite – Size: – Weight:

• Orbit – – – – –

Altitude: Orbital inclination: Orbit: Repeat: Swath width:

Landsat-1, -2, -3 • RBV • MSS – – – – –

IFOV  Total FOV: Scanner: Radiometry: Frame:

Landsat-1, -2, -3 • Scene designation – Use Worldwide Reference System (WRS) – Each orbit is a path • 001 to 251 (E –W)

– Each frame in path is row • Row 60 at equator

Landsat-4, -5 • Satellite – Size: – Weight:

• Orbit – – – – –

Altitude: Orbital inclination: Orbit: Repeat: Swath width:

Landsat-4, -5 • MSS – IFOV  – Total FOV: – Swath width:

• TM – Radiometry: – IFOV 

Landsat-4, -5 • Scene designation – Different WRS labels – Each orbit is a path • 001 to 233 (E –W)

– Each frame in path is row • Row 1 at 80° 47' N • Row 60 at equator

• Data distribution

Landsat-6 • Orbit – Planned similar to Landsat-4 and -5

• Mission – Carrying Enhanced Thematic Mapper – Failed on launch

Landsat-7 • Satellite – Similar to Landsat-4 and -5

• Orbit – – – – –

Altitude: Orbital inclination: Orbit: Repeat: Swath width:

Landsat-7 • ETM+

• Data collection

Landsat-7 Failure • Scan line corrector

http://landsat7.usgs.gov/updates.php

Landsat Applications • Commonly used sensors

• Applications

Landsat Future? • Landsat Data Continuity Mission • Options – Fully commercial – Commercial ownership: government data distribution – International consortium: government data distribution – Fully US Government operated (similar to Landsat 7)

Readings • Chapter 6: sections 6.3 – 6.9