Penggunaan Analisis Citra Digital dan Sistem Informasi Geografis untuk Prediksi Besarnya Erosi di DAS Ayung Bagian Hilir, Kabupaten Badung Propinsi Bali

Prof. Dr. Ir. I Wayan Nuarsa, M.Si., I Wayan Nuarsa (1999) Penggunaan Analisis Citra Digital dan Sistem Informasi Geografis untuk Prediksi Besarnya Erosi di DAS Ayung Bagian Hilir, Kabupaten Badung Propinsi Bali. Agritrop, 18. ISSN 0215-8620

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The objectives of the research are: (1) to know ability and accuracy of Landsat TM digital image analysis and GIS in presenting the erosion estimation variables, and (2) to estimate and to compare the erosion assessment result with direct measurement method of erosion variables in the field, in previous research at the same watershed. Calculation of erosion rate used Universal Soil Loss Equation (ULSE). Erosion components of the USLE formula was analyzed in digital form using ILWIS (Integrated Land and Watershed Information System) software version 1.4 that was able be used to digital irr.age processing and G1S based analysis. Rainfall erosivity index (R) was obtained through computation of the R-value at each rainfall station in the study area and its surrounding, and gridding process. Soil erodibility (K) was calculated from soil properties at each soil map unit and then it was linked with the graphic data. Length and slope factor (LS) was derived from topographic map by way of digitizing, rasterization, and interpolation of contour lines and elevation points. Plant and land management factor (CP) were based on landuse map that was gotten from multispectral classifIcation of Landsat TM image. Erosion rate in tonlha/year was obtained from calculation of the fourth erosion component maps. Accuracy test was applied for landuse, slope, and soil maps by means of compare analysis result with actually condition in the field. Comparisons of soil erosion estimation resulted from the method and measurement in the field was done with statistic test (ttest). The result shows that 60.15% of erosion rate in study area is classified as very slight to slight (less than 29.3 ton/ha/year), 14.58 % is included rather heavy to very heavy (more than 47 tonlhalyear), and 25.27% is grouped as moderate erosion level (29.4 -46.9 tonlha/year). The accuracy level of landuse, slope, and soil maps are 83.56%, 87.67%, and 86.30% respectively. It means thatthe accuracies are higher than the minimum limit of accuracy level acceptable. Comparison of soil erosion prediction result with early research through statistic test showed that t-calculation value is 1.02 less than t-table 5% value (1.98). Thus, integration of digital image analysis and GIS could be used to predict rate of erosion with acceptable capability and accuracy.

Item Type: Article
Uncontrolled Keywords: Remote sensing, digital image processing, geographic information system, soil erosion.
Subjects: L Education > L Education (General)
Divisions: Faculty of Law, Arts and Social Sciences > School of Education
Depositing User: Mr. Repository Admin
Date Deposited: 07 Jun 2016 21:58
Last Modified: 21 Jun 2016 05:58

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