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Pertemuan 06Fungsi Analisis pada SIG

Matakuliah : T0234 / Sistem Informasi Geografis

Tahun : 2005

Versi : 01/revisi 1

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Learning Outcomes

Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu :

• Menunjukkan fungsi-fungsi analisis dari suatu pemodelan dengan SIG (C3, TIK06)

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Outline Materi

• Materi 1 : Jenis Fungsi Analisis

• Materi 2 : Pengukuran dalam SIG

• Materi 3 : Perbedaan analisis data Raster dan Vektor

• Materi 4 : Permasalahan dalam analisis data

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Jenis Fungsi Analisis (1)

• Reclassification• Buffering• Neighborhood• Integrating data-Map Overlay• Spatial Interpolation• Analysis of Surfaces• Network Analysis

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Jenis Fungsi Analisis (2)

Reclassification : • Usually to produce a new simple code image from a

complex original image, is a very useful technique to be used in further analysis.

Original class Reclassification

1. Forest

2. Paddy field 1. Green Area….

3. …….

4. Housing

5. ……… 2. Red Area…..

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Jenis Fungsi Analisis (3)

Buffering :• Is used to identify a zone of interest around an entity or set

of entities. Buffer zones around :

Points Line

Area

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Jenis Fungsi Analisis (4)Neighborhood :• The values of individual

cells are altered on the basis of adjacency

E.q. : Filtering, will change the value of a cell based on the attributes of neighboring cells.

Applying 3x3 square filter to recalculate value for cell c4 (in the right)

6 3 3 2 1 2 2

5 3 3 2 1 1 2

4 3 2 2 2 1 1

3 2 2 2 1 1 1

2 1 2 1 1 1 1

1 1 2 1 0 0 0

a b c d e fMinimum Filter c4 = 1Maximum Filter c4 = 3 Mean Filter c4 = 1.89Modal Filter c4 = 2 (most frequently occurring class)Diversity Filter c4 = 3 (number of different classes : 1,2,3)

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Jenis Fungsi Analisis (5)

Integrating data-Map Overlay :• Vector Overlay Point in Polygon Line in Polygon Polygon on Polygon• Raster Overlay Point in Polygon (using add) Line in Polygon (using add) Polygon on polygon (using add) Polygon on polygon (Boolean alternative)

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Jenis Fungsi Analisis (6)

Spatial Interpolation :• Local or Global• Exact or approximate• Gradual or Abrupt• Deterministic or stochastic

Analysis of Surfaces :• Calculating Slope & Aspect• Visibility Analysis

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Jenis Fungsi Analisis (7)

Network Analysis :• Location-allocation Model• Route Tracing• Quantitative Spatial Analysis

– Exploratory & Descriptive Statistics– Predictive Statistics– Prescriptive Statistics

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Pengukuran dalam SIG

• Pengukuran Raster– Length

• Pythagorean Distance• Manhattan Distance• Proximity Distance

– Perimeter– Area

• Pengukuran Vector– Distance– Area

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Analisis data Raster & Vektor

Perbedaan analisis data Raster dan Vektor :- Users need to be aware of the strengths &

weakness of different type of GIS (raster & vector).- Have limitations of some of the functions they

routinely apply (e.q. length measurements).- GIS analyst should be able to produce useful

answers by combining data analysis functions into an analysis scheme.

- New analysis tools frequently start out in the academic domain

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Permasalahan dalam analisis data

Permasalahan dalam vector & raster overlay :1. The modifiable areal unit problem.

2. Ecological fallacy

3. Selecting threshold criteria

4. Visual complexity

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Penutup

• Mahasiswa diharapkan telah mampu menunjukkan fungsi-fungsi analisis dari suatu pemodelan dengan SIG.