Introduction to RemoteSensing of the Environment

Dr. Anne Nolin

Department of Geosciences

Overview of today’s lecture

• Course overview

• Definitions

• How measurements are made

• Analog vs. digital

• The remote sensing cycle

• Examples

Course Logistics• Lecture:

– MF 10:00-10:50AM

• Lab: – M 11:00 - 12:50PM (grad students)– W 10:00 - 11:50AM (undergrads)

• TA: Ofer Heyman (heymano@geo.orst.edu)• Course website:

http://www.geo.orst.edu/classes/geo444_544• Blackboard: lectures, etc. will be posted

Office Hours

Nolin:Tuesdays 1:00 - 2:00PM (Wilk 120)Wednesdays 1:00 - 2:00PM (Wilk 120)or by appointment

Heyman:Mondays 9:00AM-10:00PM (Wilk 210)Wednesdays 9:00-10:00AM (Wilk 223)or by appointment

Lab Exercises and Exams

• Labs exercises are assigned each week– due the beginning of next lab– must be submitted electronically– no credit for late work

• Exams:– Midterm: May 2– Final: June 9, 2:00 - 4:00 PM– exams are closed book

Labs will be held this week!

• See the course website for an overviewof this week’s lab

Graduate Student Project

• Remote sensing application relevant toyour area of research

• Submit short proposal to me by April 18• 2-page extended abstract due June 2• Conference-style poster presentation on

June 6• All students must attend these

presentations on June 6th

20%-0-Term Project

30%35%Labs

20%35%Final

30%30%Midterm

GEO544GEO 444Grading

Physical Principles of Electromagnetic RadiationHow satellites and sensors workOptical remote sensingThermal remote sensingPassive microwave remote sensingActive microwave remote sensingLidar and altimetryApplications: Vegetation mappingApplications: Land cover/land use changeApplications: WaterApplications: Soils, minerals, and geomorphologyApplications: Urban mapping

What is remote sensing?“the acquisition and measurement of data/informationon some property(ies) of a phenomenon, object, ormaterial by a recording device not in physical,intimate contact with the features(s) undersurveillance; techniques involve amassing knowledgepertinent to environments by measuring force fields,electromagnetic radiation, or acoustic energyemploying cameras, radiometers and scanners, lasers,radio frequency receivers, radar systems, sonar,thermal devices, seismographs, magnetometers,gravimeters, scintillometers, and other instruments”.

Source: NASA tutorial on remote sensinghttp://rst.gsfc.nasa.gov/Intro/nicktutor_I-1.html

Shorter definition

• Remote sensing is the collection ofinformation about an object or systemwithout coming into direct physicalcontact with it

• Art or science???

Why do we do remote sensing?

• Unobtrusive• Automated• Useful for extreme conditions• Offers excellent spatial and temporal

coverage• Often cost-effective• Extends our senses

How are measurements made?

• Ground-based

• Airborne

• Satellite

Remote Sensing Systems• Active Sensor - illuminates the subject from an

artificial energy source

• Passive Sensor - uses natural radiation fromthe Sun or other emitted signal

• Imaging Sensor - creates a “picture” byscanning across linear array of detectors whilethe array moves through space

• Non-imaging Sensor - measures along atransect or at a point

REMOTE SENSING DATA TYPES

Visible, infrared, thermal, and microwave are most common

Analog vs. Digital

What is analog data?– Film

Benefits of analog data:– Easy to view– High spatial resolution– Often very cost effective– Compact (photograph vs. hard drive, CDs,

or tape)

Drawbacks of analog data:– Difficult to transmit remotely

– Difficult to edit after acquisition

– Limited response to light (visible andnear infrared wavelengths only)

– Degradation over time can limitarchive capabilities

Benefits of digital data:– Wide variety of detectors

• Electromagnetic and other types• Large amplitude range

– Data easily transmitted remotely– Data easily edited by computer after

acquisition– Longterm archive

Drawbacks of digital data– Storage requirements can be large

– Requires sophisticated equipment toview

– Reduced spatial resolution (in mostcases)

The Remote Sensing Cycle

Sensor

Data

Processing

DataAnalysisInterpretation

Information

Assessment

Development

The Remote Sensing Cycle

Sensor

Data

Processing

DataAnalysisInterpretation

Information

Assessment

Development

Montana Fires, August 23 2000MODIS thermal bandsare used to map thelocation and strength of activefires, and burned areaextent.

Vegetation maps alsoprovide informationabout fire dynamics

Smoke plumes canbe tracked forhealth monitoringFires superimposed on MODIS 250m

surface reflectance product

Breakup of the Larsen B Ice Shelf

MODISimagery fromJanuary 31, 2002-March 6, 2002

Courtesy of Ted Scambos, NSIDC

GeologicMapping

withAVIRIS

Mapping the 1996 Oregon Floods

RADARSAT image 13 FebColumbia River near Portlandjust past peak flood stage.

RADARSAT image 14 Febshowing flood damaged areas

MiningWaste inLeadville,

CO

AVIRIS imageshowing distributionand types of acid-generating minerals

Lambert Glacier, Antarctica

InterferometricSyntheticAperatureRadar (InSAR)uses phasedifferencebetween twoimages todeterminemovement

Image courtesy CSA, NASA, Ohio State Univ., JPL, ASF

Wetlands ofthe Gulf Coast

Multispectral andmultiangular viewsof coastal wetlands offthe coast of Louisiana

MISR