Introduction Remote Sensing

GIMA: Geographical Information Managementand Applications

Electromagnetic (EM) spectrum

Remote sensing platforms

Remote sensing ≡ Earth observation

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

Sensor ata distance

EM radiation

Satellite image Terschelling 26 May 2018

4

Drought effect Terschelling 15 July 2018

5

Satellite image Friesland 13 May 2019

6

Satellite image Friesland 19 July 2019

7

Grassland parcels with damage by mice

8

25 July 2019: heatwave over Europe

Huge Seaweed Bloom (Sargassum)

Sargassum on Bonaire

Fires in the U.S. West: 30 August 2021

Arc of Fires U.S. West: 29 August 2021

Hurricane Ida hits Louisiana: 30 August ‘21

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. soils

3. geology

4. precipitation

5. land cover

6. vegetation

7. remote sensing data

8. surface temperature

9. hydrology

10. population

11. nature conservation

12. environment

13. digital terrain model

14. topographical map

15. -------------------

16. -------------------

17. -------------------

rasterdata

GIS file: field data(point measurements)

vectordata

Meteosat: meteorological satellite

Meteosat image of Europe

http://www.sat24.com/?culture=en

Rotterdam harbour, daytime / nighttime

The remote sensing system

A = sourceB = atmosphereC = objectD = sensorE = receptionF = data analysisG = final product

Sources of EM radiation

100

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 m0.3 0.6 1.0 5.0 10 50 10m100 1mm 1cm 1m

200 m0.3 0.6 1.0 5.0 10 50 10m100 1mm1cm 1m

multispectral scanners

microwave

window

emission

optical

window

lidar

reflection

photography

human eye

mic

row

ave

s

microwave radiometry

blocking effect of atmosphere

radar

atm

os

ph

eri

ctr

an

sm

itta

nce

UV

blu

egre

en

red

NIR

MIR

MIR

TIR

TIR

thermal scanners

VIS

wavelength

100

0

wavelength (m)

red middle- (shortwave)

infrared

near-

infraredblu

e

gre

en

dry soil

water

wet soil

vegetation

reflecta

nce (

%)

40

20

0

0.8

60

0.4 1.2 1.6 2.0 2.4

Object interaction - reflectance

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)

imaging

optics

Position of spectral bands

Meteosat

NOAA AVHRR

wavelength (m)

red middle-

infrared

near-

infraredblu

e

gre

en

dry soil

waterwet soilvegetationre

fle

cta

nce

(%

)

40

20

00.8

60

0.4 1.2 1.6 2.0 2.4

Pan: IKONOS, Quickbird, GeoEye, WorldView

Multispectral: IKONOS, Quickbird, GeoEye, WorldView

Proba-V

Sentinel-2 MSI8

42 3

Landsat OLIpan

2 3 4 5

Image Processing Options

Tape/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 analysis colour assignment segmentationdensity slicing geometric correction

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

LGN 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

AVHRR-NDVI time series 1981-2012

Credit: R. de Jong

▪ Some current RS developments

What’s up next?

Next topics:

• Spectral signature

• Multispectral scanning

• Microwave remote sensing

• Image pre-processing

• Digital image processing

See: www.geo-informatie.nl/courses/gima_rs