INTRODUCTION REMOTE SENSING

Introduction Geo-Information Science (GRS-10306)

Remote Sensing --> RS

EARTHOBSERVATION

RS is a tool; one of the sources of information !Earth

Sensor ata distance

EM energy

GIS Geographical Information System

Well-considered combination of mutually referring data sets of various kinds of position-bound thematic data(database), software inclusive

Requirement:the information layersmatch geometrically

==> OVERLAY STRUCTURE

1. topography

2. soils3. geology4. precipitation5. land cover6. vegetation7. remote sensing data8. surface temperature9. hydrology10. population11. nature conservation12. environment13. digital terrain model14. topographical map15. -------------------16. -------------------17. -------------------

rasterdata

GIS file:field data

(point measurements)

vectordata

Meteosat: meteorological satellite

Meteosat image of Europe

Wageningen, Thematic Mapper Band 4 5 3

Rotterdam harbour, daytime

Rotterdam harbour, nighttime

The remote sensing system

A = source

B = atmosphere

C = object

D = sensor

E = reception

F = data analysis

G = final product

Source of EM radiation100

10-1

10-2

10-3

10-4

0.2 0.5 2 101.0 5 20

radiation (Wcm-2 µm-1)

wavelength (µm)

REFLECTION EMISSION

emitted

thermal radiation

reflected

solar radiation

curves for an “average”object on Earth

EM Spectrum and Windows

200 µµµµm0.3 0.6 1.0 5.0 10 50 10m100 1mm 1cm 1m

200 µµµµm0.3 0.6 1.0 5.0 10 50 10m100 1mm 1cm 1m

multispectral scanners

microwavewindow

emission

opticalwindow

lidar

reflection

photography

human eye

mic

row

aves

microwave radiometry

blocking effect of atmosphere

radar

atm

osph

eric

tran

smitt

ance

UV

blue

gree

nre

d

NIR

MIR

MIR

TIR TIR

thermal scanners

VIS

wavelength

100

0

Active <-> Passive

RS using radiation emitted by objects:(PASSIVE)

RS using reflected solar radiation:(PASSIVE)

ACTIVE RS:

Principles imaging sensor systems

Pushbroom scannerWhiskbroom scanner

digital recordinganalogue recording digital recording

scanning mirrorshutter

“point” detector

aerial image plane line array detector

imaging optics imaging optics

Camera(aerial photography)

imagingoptics

The position of the spectral bands of some Remote Sensing sensor systems in the optical window

λwavelength (µm)

red middle-

infrared

near-

infraredblue

gree

n

dry soil

waterwet soil

vegetation

reflectance (%)

SPOT HRG Panchromatic

Pan: IKONOS, Quickbird, GeoEye, WorldView

Meteosat

NOAA AVHRR

Landsat TM

40

20

00.8

60

0.4 1.2 1.6 2.0 2.4

SPOT HRG multispectral

Multispectral: IKONOS, Quickbird, GeoEye, WorldView

Image Processing OptionsTape/DVD/CD: Screen:latent image → Visualization → picture 1

picture 2--------------

picture nOptions:e.g. spectral band selection filtering

displaying band composites band ratioingcontrast modification vegetation index computationhistogram equalization classificationgrey scale enhancement texture analysiscolour assignment segmentationdensity slicing geometric correctionprincipal componentstransformation

Example TM-image, band 4-3-2 (R,G,B)

RS Properties

Moreover:

� overview region

� differences and coherence

� variety of sensors, techniques, processing algorithms

� reproducible analysis

� in addition to conventional mapping

� specified data for application

� up to date information

� co-operation of human knowledge and machine operations

� capability of monitoring with time series of data

� reveals changes (change detection)

� the invisible becomes visible

� objective and quantitative data

� extrapolation of point measurements

� open up inaccessible regions

� integration with GIS

� Synopsis

� Flexibility

� Actuality

� Interactivity

� Dynamics

MERIS image of Europe

Satellite based land cover classification

Dutch land cover data base LGN5

LGN5 detail The Hague - Rotterdam

Global land cover classification - MODIS

254Unclassified

16Barren or Sparsely Vegetated

15Snow and Ice

14Cropland/Natural Vegetation Mosaic

13Urban and Built-Up

12Croplands

11Permanent Wetlands

10Grasslands

9Savannas

8Woody Savannas

7Open Shrubland

6Closed Shrubland

5Mixed Forest

4Deciduous Broadleaf Forest

3Deciduous Needleleaf Forest

2Evergreen Broadleaf Forest

1Evergreen Needleleaf Forest

0Water

255Fill Value

ColorClassLand Cover

254Unclassified

16Barren or Sparsely Vegetated

15Snow and Ice

14Cropland/Natural Vegetation Mosaic

13Urban and Built-Up

12Croplands

11Permanent Wetlands

10Grasslands

9Savannas

8Woody Savannas

7Open Shrubland

6Closed Shrubland

5Mixed Forest

4Deciduous Broadleaf Forest

3Deciduous Needleleaf Forest

2Evergreen Broadleaf Forest

1Evergreen Needleleaf Forest

0Water

255Fill Value

ColorClassLand Cover

Primary Productivity - June 2005

Primary Productivity – December 2004

Perspective view of the Aletsch glacier (CH)