Remote Sensing & GISRemote Sensing & GIS

Michael CarmonMichael Carmon

AbstractAbstract

Geographic Information Systems (GIS) are a new and blossoming concept, and Geographic Information Systems (GIS) are a new and blossoming concept, and continue to grow in complexity and utility thanks in large part to the continue to grow in complexity and utility thanks in large part to the proceeding and continual development of Remote Sensing. Remote proceeding and continual development of Remote Sensing. Remote Sensing plays a large role in the enhancement of any GIS, and in most Sensing plays a large role in the enhancement of any GIS, and in most cases, allows data to become much more relatable and useful for anyone. A cases, allows data to become much more relatable and useful for anyone. A GIS receives much of the data for its built-in layers from Remote Sensing GIS receives much of the data for its built-in layers from Remote Sensing platforms such as satellites, radars and airplanes. Passive sensors platforms such as satellites, radars and airplanes. Passive sensors contribute to imagery and data for land cover mapping, change detection, contribute to imagery and data for land cover mapping, change detection, snow monitoring, thermal changes and terrain modeling. Active sensors snow monitoring, thermal changes and terrain modeling. Active sensors contribute heavily to data for extremely accurate terrain models known as contribute heavily to data for extremely accurate terrain models known as Digital Elevation Models (DEMs). These large quantities of data can be geo-Digital Elevation Models (DEMs). These large quantities of data can be geo-referenced and integrated into one large GIS, allowing a user to access a referenced and integrated into one large GIS, allowing a user to access a powerful amount of information at one time with relative ease. And as powerful amount of information at one time with relative ease. And as remote sensing technology continues to increase in resolution and power, remote sensing technology continues to increase in resolution and power, the data base will enlarge and increase the potential power of users of a the data base will enlarge and increase the potential power of users of a Geographic Information System.Geographic Information System.

OverviewOverview

What is a GIS?What is a GIS?

The Importance of Remote Sensing in The Importance of Remote Sensing in GIScienceGIScience

RS Methods Used in GIS Data AcquisitionRS Methods Used in GIS Data Acquisition

Digital Orthophotos & Satellite ImageryDigital Orthophotos & Satellite Imagery

Radar Data: DEMsRadar Data: DEMs

The Future of GIS and Remote SensingThe Future of GIS and Remote Sensing

GIS BasicsGIS Basics Geographic Information SystemGeographic Information System

Allows the viewing and analysis of Allows the viewing and analysis of multiple layers of spatially related multiple layers of spatially related information associated with a information associated with a geographic region/locationgeographic region/location

Both spatial and attribute (tabular) Both spatial and attribute (tabular) data are integrateddata are integrated

The widespread collection and The widespread collection and integration of imagery into GIS has integration of imagery into GIS has been made possible through been made possible through remote sensingremote sensing

With the increasing technological With the increasing technological development of remote sensing, development of remote sensing, the development of GIS has the development of GIS has simultaneously acceleratedsimultaneously accelerated

The Importance of RSThe Importance of RS Large amounts of data needed, and Remote Sensing can provide itLarge amounts of data needed, and Remote Sensing can provide it

Reduces manual field work dramaticallyReduces manual field work dramatically

Allows retrieval of data for regions difficult or impossible to reach:Allows retrieval of data for regions difficult or impossible to reach: Open oceanOpen ocean Hazardous terrain (high mountains, extreme weather areas, etc.)Hazardous terrain (high mountains, extreme weather areas, etc.) Ocean depthsOcean depths AtmosphereAtmosphere

Allows for the collection of much more data in a shorter amount of Allows for the collection of much more data in a shorter amount of timetime

Leads to increased land coverage ANDLeads to increased land coverage AND Increase ground resolution of a GISIncrease ground resolution of a GIS

Digital Imagery greatly enhances a GISDigital Imagery greatly enhances a GIS DIRECTLY: Imagery can serve as a visual aidDIRECTLY: Imagery can serve as a visual aid INDIRECTLY: Can serves as a source to derive information such as…INDIRECTLY: Can serves as a source to derive information such as…

Land use/land coverLand use/land cover Atmospheric emissionsAtmospheric emissions VegetationVegetation Water bodiesWater bodies Cloud coverCloud cover Change detection (including sea ice, coastlines, sea levels, etc.)Change detection (including sea ice, coastlines, sea levels, etc.)

RS Methods in GISRS Methods in GIS

Passive Sensors: Passive Sensors: LandsatLandsat TM TM AVHRRAVHRR SpotSpot MODISMODIS IKONOSIKONOS QuickbirdQuickbird

Passive Systems: Air Photography (DOs)Passive Systems: Air Photography (DOs)

Active Sensors: RadarActive Sensors: Radar DEMsDEMs

Coarser Resolution Satellite Sensors UsedCoarser Resolution Satellite Sensors Used

LANDSAT Thematic Mapper

Good for regional coverage

30m MS resolution

15 m panchromatic resolution

Most Common Use:

Land Cover/Land Use Mapping

MODIS

36 spectral bands

Most Common Uses:

Cloud/Aerosol Properties

Ocean Color

Atmospheric Water Vapor

Sea/Atmospheric Temperatures

Higher Resolution Satellite Sensors UsedHigher Resolution Satellite Sensors Used

Quickbird

2.5 m multispectral resolution

61 cm (~2 ft.) panchromatic resolution

IKONOS

4 m visible/infrared resolution

1 m panchromatic resolution

MOST COMMON USES FOR HIGH RESOLUTION:

Accurate Base Maps

Infrastructure Mapping

Disaster Assessment (Smaller Scale)

How data is extracted:How data is extracted:

Layers such as roads (yellow) and rivers (blue) can be easily seen Layers such as roads (yellow) and rivers (blue) can be easily seen from air/satellite photosfrom air/satellite photos

This information is digitized (see next slide), separated into layers, This information is digitized (see next slide), separated into layers, and integrated into a GISand integrated into a GIS

Digitizing DataDigitizing Data MANUALMANUAL

Map is fixed to digitizer tableMap is fixed to digitizer table Control Points are digitizedControl Points are digitized Feature Boundaries are digitized in stream or point modeFeature Boundaries are digitized in stream or point mode The layer is proofed and editedThe layer is proofed and edited The layer is transformed/registered to a known systemThe layer is transformed/registered to a known system

AUTOMATED SCANNERSAUTOMATED SCANNERS Digitizing done automatically by a scannerDigitizing done automatically by a scanner There is a range of scanner qualitiesThere is a range of scanner qualities Most utilize the reflection/transmission of light to record dataMost utilize the reflection/transmission of light to record data ““Thresholding” allows for the determination of both line and point features from a hardcopy Thresholding” allows for the determination of both line and point features from a hardcopy

mapmap Editing still requiredEditing still required

DIRECT DATA ENTRYDIRECT DATA ENTRY Coordinate Geometry is used, with GPS playing a vital roleCoordinate Geometry is used, with GPS playing a vital role This involves directly entering in coordinates measured in the fieldThis involves directly entering in coordinates measured in the field These coordinates can then be tagged with attribute data These coordinates can then be tagged with attribute data This data this then downloaded to a computer and incorporated into a GISThis data this then downloaded to a computer and incorporated into a GIS

Air Photos: DOsAir Photos: DOs An An orthophotographorthophotograph is an aerial photograph that has been corrected to remove distortions is an aerial photograph that has been corrected to remove distortions

caused by:caused by: Camera opticsCamera optics TiltTilt Elevation differencesElevation differences

Digital Conversion (“Registration”)Digital Conversion (“Registration”) Must be converted to digital format before integration into a GISMust be converted to digital format before integration into a GIS Photograph is split into many pixelsPhotograph is split into many pixels Distortion at each point must be calculatedDistortion at each point must be calculated A photograph is considered registered when each pixel has its exact position (geographically) placed A photograph is considered registered when each pixel has its exact position (geographically) placed

with the above distortions having been taken into accountwith the above distortions having been taken into account

These registered air photos can then be used to extract data or as a base map for a GIS (or These registered air photos can then be used to extract data or as a base map for a GIS (or both)both)

Radar Data: DEMsRadar Data: DEMs Active sensors provide the Active sensors provide the

most thorough, accurate and most thorough, accurate and intricate model of topographyintricate model of topography

Radar can reach places nearly Radar can reach places nearly impossible to survey manuallyimpossible to survey manually

Interferometric Synthetic Interferometric Synthetic Aperture RadarAperture Radar Two passes of a radar satellite Two passes of a radar satellite

are usedare used Any phase difference of Any phase difference of

returned echoes yields returned echoes yields information about the angle information about the angle from which the echo was from which the echo was returnedreturned

Allows for topographic Allows for topographic information to be derivedinformation to be derived

]cossin[2 yx BB

)(cosHh

h is pixel height and phi is phase difference:

This image was created by overlaying a 1m resolution DO on a This image was created by overlaying a 1m resolution DO on a

DEM of the same area (both utilize the same projection)DEM of the same area (both utilize the same projection)

Source: http://www.sco.wisc.edu/maps/digitalelevation.php#GISSource: http://www.sco.wisc.edu/maps/digitalelevation.php#GIS

ApplicationsApplications

Change DetectionChange Detection Disaster AssessmentDisaster Assessment

Hurricane Katrina & RitaHurricane Katrina & Rita 2004 Tsunami2004 Tsunami

Atmospheric ModelingAtmospheric Modeling aerosolsaerosols air pollutionair pollution climate changeclimate change

OceanOcean topographytopography currentscurrents

Future of GIS & RS: Worldview IFuture of GIS & RS: Worldview I

Launched in September 2007Launched in September 2007 Provides ½ m resolution images (Houston, TX above)Provides ½ m resolution images (Houston, TX above) Images such as the one above will become increasingly common and will provide more Images such as the one above will become increasingly common and will provide more

accurate data for a GISaccurate data for a GIS

AltitudeAltitude: 496 km: 496 km

Orbit TypeOrbit Type: Sun-Synchronous : Sun-Synchronous

Swath width at nadirSwath width at nadir: 17.6 km: 17.6 km

Orbit TimeOrbit Time: 94.6 minutes: 94.6 minutes

Panchromatic ImageryPanchromatic Imagery

More Worldview I Images

Issues of Remote Sensing & GIS Issues of Remote Sensing & GIS in the Futurein the Future

User interfaces continue to become more standardizedUser interfaces continue to become more standardized An increased number of RS platforms is leading to more accurate and An increased number of RS platforms is leading to more accurate and

more easily acquirable datamore easily acquirable data Geospatial Law & Privacy IssuesGeospatial Law & Privacy Issues

becoming more of an issue as resolution increasesbecoming more of an issue as resolution increases who has a right to be looking at pictures of one’s home in ½ m resolution?who has a right to be looking at pictures of one’s home in ½ m resolution?

GIS is becoming more globally acceptedGIS is becoming more globally accepted Increasing resolutions of RS platforms has lead to increasing amounts Increasing resolutions of RS platforms has lead to increasing amounts

of dataof data can the large amount of data be handled and stored efficiently?can the large amount of data be handled and stored efficiently? can this data be incorporated into a GIS that is not overwhelmingly large?can this data be incorporated into a GIS that is not overwhelmingly large?

The current era (and times to come, most likely) continues to The current era (and times to come, most likely) continues to emphasize visualization of informationemphasize visualization of information Remote Sensing images are Remote Sensing images are keykey to this aspect to this aspect

SourcesSources

Allen, C. “An Interferometric Technique for Synthetic Allen, C. “An Interferometric Technique for Synthetic Aperture Ground-Penetrating Radar.” Aperture Ground-Penetrating Radar.” Geoscience and Geoscience and Remote Sensing Symposium.Remote Sensing Symposium. 4 (1996): 2033-2035. 4 (1996): 2033-2035.

Bolstad, Paul. Bolstad, Paul. Fundamentals of GIS, 2Fundamentals of GIS, 2ndnd ed. ed. Atlas Books, Atlas Books, 2005.2005.

Environmental Systems Research Institute (ESRI): Environmental Systems Research Institute (ESRI): http://www.esri.comhttp://www.esri.com

Lillesand, Thomas M., Ralph W. Kiefer and Jonathan W. Lillesand, Thomas M., Ralph W. Kiefer and Jonathan W. Chipman. Chipman. Remote Sensing and Image Interpretation, 5Remote Sensing and Image Interpretation, 5thth ed.ed. Wiley, New York, 2004. Wiley, New York, 2004.

NASA: http://www.nasa.govNASA: http://www.nasa.gov http://www.ccrs.nrcan.gc.ca/glossary/index_e.php?http://www.ccrs.nrcan.gc.ca/glossary/index_e.php?

id=3054id=3054 Sattellite Imaging Corps: http://www.satimagingcorp.comSattellite Imaging Corps: http://www.satimagingcorp.com United States Geological Survey: http://www.usgs.govUnited States Geological Survey: http://www.usgs.gov