Introduction to Remote Sensing

GISG120

Michelle Kinzel

San Diego Mesa College GIS

What is ‘remote sensing’?

What is ‘remote sensing’?

"The use of electronic sensors (or photography) to acquire data related to the electromagnetic spectrum in formats that can be analyzed numerically and/or that result in images (pictures) of objects/scenes located in the field of view, all of which can then be applied to the study of the land, sea, air and biotic communities that comprise Earth's environments, as well as the principal means for obtaining a deep understanding of the vital role remote sensing plays in exploring the planets and observing the stars and galaxies well out into the Cosmos."

Shorter definition

• Remote sensing is the collection of information about an object or system without coming into direct physical contact with it

• Art or science???

Syllabus and Course Expectations

By the end of the term you will be able to:

• 1. Define and describe remote sensing and explain its applications and history.

• 2. Define and describe basics of electromagnetic spectrum and interactions with various types of media.

• 3. Describe sensors and image acquisition methods.• 4. Analyze and explain remote sensing purposes,

advantages, and limitations.• 5. Describe basic characteristics of remote sensing

imagery.• 6. Describe industry-specific image sources, acquire

images and apply digital imaging techniques appropriate for an industry-specific project.

How will your earn your grade?

• Lab exercises• Midterm• Student Project

Student Project

Remote sensing application relevant to your area of interestPart I: Submit a short, 1-page proposal Part II: Present a Powerpoint Presentation of your

project

We will have a conference style presentation of student projects

ALL ARE REQUIRED TO ATTEND (THIS IS PART OF YOUR FINAL EXAM GRADE)

Topics we will cover:Physical principlesHow satellites and sensors workTypes of sensors: Optical

ThermalPassive microwaveActive microwaveLidar and altimetry

Applications: Vegetation mapping and assessment Land cover/land use change Water (oceans, lakes, rivers, snow/ice) Soils, minerals, and geomorphology Urban and societal applications

A Brief Introduction to Remote Sensing and Some Examples

What is ‘remote sensing’?Remote sensing involves the use of instruments or sensors to "capture" the spectral and spatial relations of objects and materials observable at a distance - typically from above them.

What is ‘remote sensing’?Remote sensing is the process of acquiring data/information about objects/substances not in direct contact with the sensor, by gathering its inputs using electromagnetic radiation, acoustical waves, or force fields that emanate from the targets of interest.

What is ‘remote sensing’?

An aerial photograph is a common example of a remotely sensed (by camera and film, or now digital product.

Why do we do remote sensing?

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

coverage• Provides real time or near-real time

observations• 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 from the Sun or other emitted signal

• Imaging Sensor - creates a “picture” by scanning across a linear array of detectors while the array moves through space

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

REMOTE SENSING DATA TYPES

Visible, infrared, thermal, and microwave are most common

The Remote Sensing Cycle

Sensor

Data

Processing

DataAnalysis

Interpretation

Information

Assessment

Development

The Remote Sensing Cycle

Sensor

Data

Processing

DataAnalysis

Interpretation

Information

Assessment

Development

Some examples…

Sea Surface Height

Potential Flood Danger

Mapping Flooding in New Orleans

Lidar-derived water depths superimposed over a high resolution SPOT image

Fire MappingThermal channels are used to map the location and strength of active fires, and burned areaextent.

Vegetation maps provide information about fire dynamics

Smoke plumes are tracked for health monitoring

Magpie Fire Burn Scar Yellowstone NP, August 2006

Breakup of the Larsen B Ice Shelf

MODISimagery fromJanuary 31, 2002-March 6, 2002

Courtesy of Ted Scambos, NSIDC

Mining Waste in Leadville, CO

AVIRIS image showing distribution and types of acid-generating minerals

Wetlands of the Gulf Coast

Multispectral and multiangular viewsof coastal wetlands off the Gulf Coast

MISR