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TOWARD A FULLY AND ABSOLUTELY RASTER-BASED EROSION MODELING BY USING RS AND GIS Bambang Sulistyo; Totok Gunawan; Hartono .; Projo Danoedoro
Indonesian Journal of Geography Vol 41, No 2 (2009): Indonesian Journal of Geography
Publisher : Faculty of Geography, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijg.2269

Abstract

The erosion map data is one of important data used in planningconservation of degraded land. Generally, erosion data is predicted using a modelbecause to gain actual erosion requires much resource (timely, costly and labourintensive). USLE (Universal Soil Loss Equation) is one of existing erosion modelsapplied worlwide, including Indonesia. Nevertheless, erosion analysis conducted isbased on analysis using vector-based maps. This method involves simplification,either algorithms or procedures, and subject to subjectivity, so the result has highuncertainty. This article deals with the idea to build a fully raster-based erosionmodeling. Steps required to obtain raster-based data was highlighted as from thebeginning up to the model validation to get an absolute model. The integration ofremote sensing and GIS was inevitably usedfor the analysis.
Application of Geographically Weighted Regression for Vulnerable Area Mapping of Leptospirosis in Bantul District Prima Widayani; Totok Gunawan; Projo Danoedoro; Sugeng Juwono Mardihusodo
Indonesian Journal of Geography Vol 48, No 2 (2016): Indonesian Journal of Geography
Publisher : Faculty of Geography, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (3239.139 KB) | DOI: 10.22146/ijg.17601

Abstract

Abstract Geographically Weighted Regression (GWR) is regression model that developed for data modeling with continuous respond variable and considering the spatial or location aspect. Leptospirosis case happened in some regions in Indonesia, including in Bantul District, Special Region of Yogyakarta. The purpose of this study are to determine local and global variable in making vulnerable area model of Leptospirosis disease, determine the best type of weighting function and make vulnerable area map of Leptospirosis. Alos satelite imagery as primary data to get settlement and paddy fields area. The others variable are the percentage of population’s age, flood risk, and the number of health facility that obtained from secondary data. Determinant variables that affect locally are flood risk, health facility, percentage of age 25-50 years old and the percentage of settlement area. Meanwhile, independent variable that affects globally is the percentage of paddy fields area. Vulnerability map of Leptospirosis disease resulted from the best GWR model which used weighting function Fixed Bisquare. There are 3 vulnerable area of Leptospirosis disease, high vulnerability area located in the middle of Bantul District, meanwhile the medium and low vulnerability area showed clustered pattern in the side of Bantul District. Abstrak Geographically Weighted Regression (GWR) adalah model regresi yang dikembangkan untuk memodelkan data dengan variabel respon yang bersifat kontinu dan mempertimbangkan aspek spasial atau lokasi.  Kejadian Leptospirosis terjadi di beberapa wilayah di Indonesia termasuk di wilayah Kabupaten Bantul Daerah Istimewa Yogyakarta. Tujuan dari penelitian ini adalah menentukan variabel lokal dan global dalam membuat model  kerentanan Leptospirosis dan menentukan jenis fungsi pembobot yang terbaik serta membuat peta kerentanan wilayah Leptospirosis menggunakan aplikasi GWR. Citra Satelit Alos digunakan untuk mendapatkan data penggunaan lahan, yang selanjutnya diturunkan menjadi prosentase luas permukiman dan sawah. Parameter lainya adalah prosentase umur penduduk, resiko banjir dan jumlah fasilitas kesehatan yang diperoleh dari data sekunder. Variabel yang berpengaruh secara lokal adalah  Risiko Banjir, Fasilitas Kesehatan Presentase Usia 25-50 tahun, Prosentase Luas Pemukiman, sedangkan variabel independen yang bepengaruh secara global adalah Presentase Luas Sawah.  Peta kerentanan Leptospirosis yang dihasilkan dari model GWR terbaik yaitu menggunakan fungsi pembobot  Fixed Bisquare. Terdapat 3 kelas kerentanan Leptospirosis yaitu kelas kerentanan tinggi berada di desa-desa di tengah Kabupaten Bantul, sedangkan kelas sedang dan rendah menunjukkan pola menggelompok di wilayah pinggiran Kabupaten Bantul
PROPOSED MODEL ON LEVELS OF DEGRADED LAND AT MERAWU WATERSHED, BANJARNEGARA REGENCY, CENTRAL JAVA PROVINCE, INDONESIA Bambang Sulistyo; Totok Gunawan; Hartono Hartono; Projo Danoedoro; Rochmat Martanto
BIOTROPIA - The Southeast Asian Journal of Tropical Biology Vol. 24 No. 3 (2017)
Publisher : SEAMEO BIOTROP

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11598/btb.2017.24.3.730

Abstract

Conservation of degraded land in Indonesia requires maps of degraded land. The maps were established based on a model developed in 1998 by the then Indonesia Department of Forestry. The model has 2 weaknesses i.e. 1. high level of uncertainty due to vector-based data used to build the thematic maps and 2. parameters redundancy or duplication from the model. This research was aimed to build up a proposed model on levels of degraded land at Merawu Watershed using fully raster-based data supported with remote sensing and GIS techniques. Parameters analyzed were Slope, Erosivity (R), Erodibility (K), Slope Length and Steepness (LS), Cover and Management (C), Support Practice (P) and Percentage of Canopy Cover. These data were presented in fully raster format. Management parameter was not explicitly used in this research because management parameter was already represented by the C and P parameters . Five parameters were directly obtained using fully raster format, i.e. Slope, LS, C, P and Percentage of Canopy Cover. The other 2 parameters went through spatial interpolation process before being presented as fully raster format. Correlation analysis among parameters was carried out. Parameters having high correlation coefficient (r ≥ 0.8) were excluded from the model to avoid redundancy. The proposed model only used parameters having low correlation coefficient. The research result showed that the determination of levels of degraded land was more accurate when using only erosion parameters, formulated as:Level of Degraded Land (LoDL) ≈ Erosion ≈ R x K x LS x C x P.Â