Change Detection Studies using RS

Presented by: Tilok Chetri

M.Sc. GIS and RS

Remote sensing is a method of obtaining information about the properties of an object without coming into physical contact with it.

A) Energy Source

B) Atmosphere & Radiation

C) Interaction with the target &

recording of the ref. energy

D) Transmission & ground level

processing

E) Interpretation, Analysis and

Application

Source: GrindGIS

Remote Sensing

RS system capture radiation in different wavelength

reflected/emitted by the earth’s surface features and recorded

it either directly on the film as in case of aerial photography or

in digital medium used for generating the images

It provides valuable data over vast area in a short time about

resources, meteorology and environment leading to better

resource management and accelerating national development

Remote Sensing

Change detection in GIS is a method of understanding

how a given area has changed between two or more

time periods.

It is helpful in many applications such as:• Land use changes

• Rate of deforestation

• Coastal change

• Urban sprawl

Change detection involves comparing changes

between aerial photographs taken over different time

periods that cover the exact same geographic area.

Change Detection

• Urban change

• Environmental change, drought monitoring, flood monitoring, monitoring

• Coastal marine environments, desertification, and detection of landslide areas

• Other applications such as crop monitoring, shifting cultivation monitoring

• Wetland change

Applications of Change Detection Techniques

• Land-use and land-cover (LULC) change

• Forest or vegetation change• Forest mortality, defoliation and

damage assessment• Deforestation, regeneration and

selective logging• Road segments, and change in

glacier mass balance.• Forest fire and fire-affected area

detection• Landscape change

Change detection can be used to measure four different types of change:

o Change in the identify of a feature over time

o Change of a feature’s location over time

o Change of a feature’s shape over time

o Change in a feature’s size over time.

Change Detection

Change Detection Procedure

Image selection

Multi-temporal Analysis

Image Registration

Radiometric & Atmospheric corrections

Change detection

Good change detection research should provide the following information's:

Area change and change rate Spatial distribution of changed types Change trajectories of land-cover types Accuracy assessment of change detection results

Some Change Detection Techniques

Source: I.R. Hegazy, M.R. Kaloop / International Journal of Sustainable Built Environment 4 (2015) 117–124

1985 2000

2010

Mansoura and Talkha land use maps

Four land cover maps (A. 2007, B. 2008, C. 2009, and D. 2010) and locations of concession and conservation areas including deforested landscape observed in 2007e2010 (E).

Source:Soraya Violini, Deforestation: Change Detection in Forest Cover using Remote Sensing

o Monitoring urban growth and land use change detection with GIS and remote sensing techniques in Daqahlia governorate Egypt- Ibrahim Rizk Hegazy 2015

o PETIT, C. C., and LAMBIN, E. F., 2001, Integration of multi-source remote sensing data for land cover change detection. International Journal of Geographical Information Science, 15, 785–803

o Google Time-Lapse video(1984-2016)

References

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Notes:Change detection can be used to measure four different types of change:

Change in the identify of a feature over time.    For example, the change in type of retail store at a given location.  A local restaurant may go out of business and be replaced by a toy store.  The actual physical building hasn’t changed, the type of categorized land use hasn’t change (commercial), but the specific identity of the store has change.

Change of a feature’s location over time.  Change detection can be used to track the movement of a feature.

Change of a feature’s shape over time. Change detection can be used to understand shrinkage in a specific specie’s habitat over time or the changes in the shape of a river or lake.

Change in a feature’s size over time. Change detection can also measure the extent of a feature.  Does the urban area grow or shrink between two time points?