RS and GIS: UWGB 2011

Dutch, Fermanich and Stiefvater

Remote Sensing

http://www.cas.sc.edu/geog/rslab/Rscc/rscc-frames.html

What is Remote Sensing?• Acquisition of physical data of an object without

touch or contact.• Observation of a target by a device separate

from it by some distance.• ”Reconnaissance at a distance.”• Depends on context.• Some definitions include Geophysical (seismic,

magnetic, gravitational, acoustical, & nuclear decay radiation surveys)

• These days usually implies more than mere visual processing

What Sensors Detect

• Electromagnetic radiation– Radio– Infrared (thermal)– Visible– Ultraviolet– X-Ray and gamma ray

• Force fields– Gravity– Magnetism

• Acoustic energy– Audible– Ultrasonic– Infrasonic– Seismic

Sensors

• Cameras• Radiometers and scanners• Lasers• Radio frequency receivers• Radar systems• Sonar• Thermal devices• Seismographs• Magnetometers• Gravimeters• Scintillometers

Fig. 18-2, p.430

Remote Sensing

http://www.cas.sc.edu/geog/rslab/Rscc/rscc-frames.html

• Source of the radiation being sensed may or may not be independent of the sensing device.

• Passive remote sensing relies on the radiation originating from some other source, principally the sun.– Often Visible, NIR

• Source of the radiation being sensed may or may not be independent of the sensing device.

• Active remote sensing devices, such as radar, direct radiation of a particular form towards an object and then detect the amount of that energy which is radiated by the object. – microwave and radio wave regions

of the EM spectrum. – Lidar (Laser Imaging raDAR)

systems :ultraviolet, visible and near infrared wavelengths.)

Applications

Land Use Geology Hydrology Vegetation Soils

GIS

Extracted Info

Sensor Data

Physical Object

Geographic Information Systems (GIS)

• Data– Vector– Raster

• Metadata (Data About the Data)– When, how, by whom acquired– What the data means– How accurate is the Data– How the Computer should deal with Data

Image of the day• Where:

Southern Chile

• When: January 19, 2009

       Chaiten Volcano, Chile

Image of the day• Where: Southern Chile• When: January 19, 2009• What’s being sensed?

– Ash plume and previous ash falls– Dispersal patterns and paths

• Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER)– Multi spectral including visible and IR

• Satellite: NASA’s Terra (launched Feb. 2000)

Why Chaiten is Neat

Image of the Day

• Rehearse

• Scale, location, orientation

• Be able to pronounce terms correctly

• Anticipate questions– Effects on people and environment– Unusual features in image– How data acquired