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EVALUASI LAHAN UNTUK DASAR PENGEMBANGAN PERTANIAN TANAMAN SEMUSIM (Kasus di Raumoco Lautem Timor Leste) Antonio Joao Da Costa; Bambang Hendro Sunarminto; Totok Gunawan; Sri Nuryani Hidayah Utami

Publisher : Fapetrik-UMPAR

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (19.014 KB) | DOI: 10.31850/jgt.v4i2.104

Abstract

Remote sensing techniques for interpretation of landsurface physical variables related to hydrological phenomena in Lembang Area, West Java, Indonesia Totok Gunawan
Indonesian Journal of Geography Vol 18, No 56 (1988): Indonesian Journal of Geogrphy
Publisher : Faculty of Geography, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijg.2183

Abstract

The variables related to the hydrological processes within a watershed are considered in four categories: climate, landsurface physical processes, and output variables. Based on the properties of the image of the remotely sensed document, landsurface physical variable is one of these categories which is directly visible on the image, in a broad sense, they may vary from landform to geometrical aspect of channel. On the other hand, features that are not visible on the image, such as, underlying formation, can be deduced from related features that are directly visible.The principal methods of aerial photographic interpretation based on the pattern analysis of the landscape features and the division to the smaller features, are characterized by local pattern elements. The aims of the study are: (i) to get appropriate information about landsurface physical variables through aerial photographic interpretation, (ii) to determine and describe the interrelationship between selected landsurface physical variables and the hydrological processes.The geologic structure of•fault of Lembang area changes the landsurface physical condition, such as, surface drainage pattern, drainage density, landform and local slope, and land use. This fault and the landsurface physical changes appear on the image clearly. The development of the surface drainage is shown quite differently between
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
Utilization of Remote Sensing Techniques for Monitoring and Evaluation of Solo Watershed Management Totok Gunawan
Forum Geografi Vol 17, No 2 (2003)
Publisher : Universitas Muhammadiyah Surakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23917/forgeo.v17i2.532

Abstract

This research is an application of remote sensing technology for monitoring and evaluation of watershed management, which was conducted is Solo Watershed, Central and East Java. The research objectives were 1) to investigate the capability of photomorphic analysis of Landsat Thematic Mapper (TM) and Enhanced Themmatic Mapper (ETM +) imagery as the basic for analyzes of landforms, landuse, and morphometry of the land surface; 2) to calculate the overland flow – peak discharge and erosion – sediment yield as indicators of land degradation of the area; 3) to use the indicators as set of instrument for monitoring and evaluation of watershed management. In this study, visual interpretation by means of on-screen digilization of the digital imagery was carried out in order to identify and to delineate land parameters using photomorphic approach. Based on the photomorphic analysis, several image – based parameters such as relief topography, physical soil characteristic, litho – stratigraphy, and vegetation cover were integrated with other themati maps in a geographic information system (GIS) environment. Estimation of overland flow (C) based on Cook methods (1942) and calculation of peak disccharge (Qmax) based on rational method (Qmax = C. I. A) were applied. Meanwhile, estimation of surface erosion was carried out using Universal Soil Loss Equation (USLE, A = R. K. L. S. CP). The sediment yield (Sy) was estimated using seddiment delivery ratio ( SDR) based on the following formula: Sy = [A + (25% x A)] x SDR. Both pairs of C – Qmax and A – Sy, were utilized as the basis for monitoring and evaluation of the watershed. The combination of C – Qmax and A – Sy were also used as the basis for selection of stream gauge setting / AWLR within particular sub – catchment. It was found that the photomorphic analysis is only color/tone, slope aspects, pattern, and texture, unit boundaries between volcanic – origin landscape (Wilis volcanic complex) and folded – hills landforms (Kendeng ridges) can be delineated. Within the volcanic features, coarse – textured units indicating pyroclastic materials with high drainage density (western part of Lawu volcano). In terms of calculated overland flow and peak discharge of 100 sub – catchment within the Solo Watershed, it was found that there are four sub – catchment with relatively high values ( 0.60 and 1200 m3s1 for overland flow and peak discharge repectively), namely Samin (Karanganyar), Keduang (Wonogiri), Dengkeng (Klaten), and Sungkur (Ponorogo). Five sub-catchment might be categorized as having moderate peak discharge (Qmax ranges from 1000 – 1200 m3s1), namely Ketonggo (Ngawi), Keyang (Ponorogo), Gandong – Semawur (Magetan), Pepe (Boyolali), and Soko (Bojonegoro), while the remaining 91 sub-catchments are categorized as having low peak discharge. Based on the calculation of erosion and sediment yield, there was no sub-catchment with moderate category (60 – 180 ton ha1yr1), i.e. Samin (Karanganyar), Gonggong (Magetan), Ngisip and Kedung Cilik (Tuban), and Pepe (Boyolali). The other 95 sub-catchment might be categorized as gentle to good. In terms of values representing overland flow – flood and erosion – sediment yield, there are several sub-catchments require first priority in monitoring and evaluation, and are recommended as suitable sites for stream gauge setting, i.e. Samin (Karanganyar), Gonggong (Magetan), Ngisip and Kedung Cilik (Tuban).
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