Sanjiwana Arjasakusuma, Sanjiwana
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ASSESSMENT OF MANGROVE FOREST DEGRADATION THROUGH CANOPY FRACTIONAL COVER IN KARIMUNJAWA ISLAND, CENTRAL JAVA, INDONESIA Kamal, Muhammad; Hartono, Hartono; Wicaksono, Pramaditya; Adi, Novi Susetyo; Arjasakusuma, Sanjiwana
Geoplanning: Journal of Geomatics and Planning Vol 3, No 2 (2016): (October 2016)
Publisher : Department of Urban and Regional Planning, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/geoplanning.3.2.107-116

Abstract

The Karimunjawa Islands mangrove forest has been subjected to various direct and indirect human disturbances in the recent years. If not properly managed, this disturbance will lead to the degradation of mangrove habitat health. Assessing forest canopy fractional cover (fc) using remote sensing data is one way of measuring mangrove forest degradation. This study aims to (1) estimate the forest canopy fc using a semi-empirical method, (2) assess the accuracy of the fc estimation and (3) create mangrove forest degradation from the canopy fc results. A sample set of in-situ fc was collected using the hemispherical camera for model development and accuracy assessment purposes. We developed semi-empirical relationship models between pixel values of ALOS AVNIR-2 image (10 m pixel size) and field fc, using Enhanced Vegetation Index (EVI) as a proxy of the image spectral response. The results show that the EVI provides reasonable estimation accuracy of mangrove canopy fc in Karimunjawa Island with the values ranged from 0.17 to 0.96 (n = 69). The low fc values correspond to vegetation opening and gaps caused by human activities or mangrove dieback. The high fc values correspond to the healthy and dense mangrove stands, especially the Rhizophora sp formation at the seafront. The results of this research justify the use of simple canopy fractional cover model for assessing the mangrove forest degradation status in the study area. Further research is needed to test the applicability of this approach at different sites.
Accuracy and Spatial Pattern Assessment of Forest Cover Change Datasets in Central Kalimantan Arjasakusuma, Sanjiwana; Pribadi, Uji Astrono; Seta, Gilang Aria
Indonesian Journal of Geography Vol 50, No 2 (2018): Indonesian Journal of Geography
Publisher : Faculty of Geography, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (71.575 KB) | DOI: 10.22146/ijg.16469

Abstract

The accurate information of forest cover change is important to measure the amount of carbon release and sink. The newly-available remote sensing based products and method such as Daichi Forest/Non-Forest (FNF), Global Forest Change (GFC) datasets and Semi-automatic Claslite systems offers the benefit to derive these information in a quick and simple manner. We measured the accuracy by constructing area-proportion error matrix from 388 random sample points and assessed the consistency analysis by looking at the spatial pattern of deforestation and regrowth from built-up area, roads, and rivers from 2010 – 2015 in Katingan district, Central Kalimantan. Accuracy assessment showed that those 3 datasets indicate low to medium accuracy level in which the highest accuracy was achieved by Claslite who produced 71 % ± 5 % of overall accuracy. The consistency analysis provides a similar spatial pattern of deforestation and regrowth measured from the road, river, and built-up area though their distance sensitivity are different one to another. 
EKSTRAKSI INFORMASI PENUTUP LAHAN MENGGUNAKAN SPEKTROMETER LAPANGAN SEBAGAI MASUKAN ENDMEMBER PADA DATA HIPERSPEKTRAL RESOLUSI SEDANG Kamal, Muhammad; Arjasakusuma, Sanjiwana
GEOMATIKA Vol 16, No 2 (2010)
Publisher : Badan Informasi Geospasial in Partnership with MAPIN

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (613.921 KB) | DOI: 10.24895/JIG.2010.16-2.240

Abstract

Hyperspectral sensor captures a large number of narrow and contiguous spectral bands, mostly covering from 400 to 2500 nm of electromagnetic spectrum. This characteristics offer recognition of high-detailed object spectral reflectance, which serve as basic information on object analysis using hyperspectral data. This research aims to study the applicability of field-based endmember collection as input for land cover mapping, and assess the accuracy of resulted map. The mapping algorithm used was Spectral Angle Mapper (SAM), which compares the angle between endmember’s vector and each pixel’s vector in n-dimension space. Smaller angle values indicate higher similarity between pixels and the endmember. The result of this research is a land cover map of 26 land cover classes, with overall accuracy of 60.82% (Kappa 0.52). Overall, the utility of field-based spectrometer for endmember input is potentially high; however, the effect of time difference between data acquisition and field work and image resolution is remains problematic.Keywords: hyperspectral, endmembers, field spectrometer, spectral angle mapper, land cover.ABSTRAKSensor hiperspektral merekam saluran spektral yang sangat banyak, dengan julat tiap saluran sempit, yang umumnya beroperasi pada spektrum 400 – 2500 nm. Karakeristik ini dapat memberikan pola reflektansi spektral obyek yang sangat rinci, yang bertindak sebagai informasi dasar dalam analisis obyek menggunakan data hiperspektral. Penelitian ini bertujuan untuk mengkaji penerapan teknik pengambilan endmember berbasis lapangan sebagai masukan untuk penutup lahan, dan menilai akurasi hasilnya. Algoritma pemetaan yang digunakan adalah Spectral Angle Mapper (SAM), yaitu dengan membandingkan sudut antara vektor endmembers dan tiap vektor piksel dalam ruang n-dimensi. Semakin kecil sudut piksel terhadap suatu endmember maka semakin sesuai piksel untuk masuk ke dalam kelas endmember tersebut. Hasil klasifikasi berupa peta penutup lahan untuk 26 kelas penutup lahan, dengan akurasi keseluruhan sebesar 60,82% (Kappa 0,52). Secara keseluruhan, utilitas spektrometer lapangan untuk mengumpulkan endmember berbasis lapangan berpotensi tinggi, namun dampak yang disebabkan oleh perbedaan waktu akuisisi citra dan kerja lapangan dan resolusi citra masih menjadi problem.Kata Kunci: Hiperspektral, endmembers, spectrometer lapangan, spectral angle mapper, penggunaan lahan.
LAND-SOIL CHARACTERISTICS FOR MAPPING PADDY CROPPING INTENSITY USING DECISION TREE ANALYSIS FROM SINGLE DATE ALI IMAGERY IN MAGELANG, CENTRAL JAVA, INDONESIA Arjasakusuma, Sanjiwana; Danoedoro, Projo; Herumurti, Sigit; Nugroho, Yanuar Adji; Aryaguna, Prama Ardha
Geoplanning: Journal of Geomatics and Planning Vol 4, No 2 (2017): (October 2017)
Publisher : Department of Urban and Regional Planning, Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/geoplanning.0.0.%p

Abstract

Paddy field area and its cropping intensity are main information used to measure the crop production and the response of crop to changing climate conditions. Remote sensing technology has been used widely to map cropping pattern of paddy mostly using spectral analysis of multi temporal multispectral data of remote sensing. However, the cropping intensity of paddy was also influenced by the characteristics of planted land to paddy field which defines the level of land suitability for planting paddy.  This research aimed to map paddy rotation by using single date ALI imagery by assessing the land and soil characteristics based on the land suitability parameters for planting paddy.  Soil characteristics such as texture, acidity level, P205 (phosphor) and C-organic level collected from field work and terrain characteristics such as landform, surface water, and drainage density from visual delineation of SRTM 90 m was collected as inputs for the decision tree analysis to map the repetition of paddy planting throughout the year. The results showed the overall accuracy of 85% ± 8% (95 % level of confidence) for the final paddy rotation map where 2-times paddy per year was mostly found in the study area.