Influence of Spatial Abilities on Spatial Data Quality in Participatory Mapping

Participatory mapping (PM) method has become an alternative in spatial data collection activities for various mapping activities, including updating data on Rural & Urban Land and Building Tax (PBB-P2). From several experiences in PM application, various quality results have been found. Differences in the levels of spatial abilities of PM actors are assumed to affect the quality levels of PM results. Therefore, this study aimed to determine the effects of spatial abilities on the quality of spatial data generated in PM activities. It consisted of several stages of preparing instruments for measuring spatial abilities, collecting spatial data through PM, and correlation analysis. The instrument used to measure the levels of spatial abilities of 28 subvillage chiefs was the Purdue Spatial Visualization Test. The quality of PBB-P2 spatial data in 28 subvillages was randomly selected and assessed in terms of position, area, and geometric accuracies with reference to the land registration map from National Land Agency. Results indicated a positive correlation between the visual spatial ability and the spatial data quality of the PM results with a value of r = 0.823. Our findings are expected to be used as references for parties who carry out PM activities to be able to plan such activities

Pemanfaatan Informasi Geospasial Dasar (IGD) untuk Analisis Penyimpangan Arah Kiblat Bangunan Masjid secara Masal

Basic geospatial information that has been widely disseminated to the general public needs to be utilized optimally for various purposes related to spatial analysis. The city of Bandung is one of the cities with the largest muslim population and the largest mosque building in Indonesia. This study aims to analyze the mass deviation of the direction of mosque buildings, especially those that have been established in Cibeunying Kidul District, Bandung City. The method used is geovisual analysis by comparing the direction of the mosque's qibla which is calculated using the vincenty method to the direction of the mosque building obtained from the 1:1.000 scale RBI map, orthophoto and Mosque Information System (SIMAS). The calculation results show that only the Al Balad Mosque building leads to the city of Mecca. The average magnitude of the deviation from the qibla direction of the mosque building to the Kaaba is 150 1' 0,365 ". There are several factors that are identified visually and the correlation can affect the deviation value of the direction of the mosque building, including the direction of building density of 27.688% and the basic coefficient of mosque building of 14,001%.Informasi geospasial dasar yang telah menyebar luas kepada masyarakat umum perlu dimanfaatkan secara optimal untuk berbagai keperluan terkait analisis spasial. Kota Bandung merupakan salah satu kota dengan jumlah penduduk muslim dan bangunan masjid terbanyak di Indonesia. Penelitian ini bertujuan untuk menganalisis secara masal penyimpangan arah bangunan masjid, khususnya yang telah berdiri di Kecamatan Cibeunying Kidul, Kota Bandung. Metode yang digunakan adalah analisis geovisual dengan cara membandingkan arah kiblat masjid yang dihitung menggunakan metode vincenty terhadap arah bangunan masjid yang diperoleh dari peta RBI skala 1:1.000, orthophoto dan Sistem Informasi Masjid (SIMAS). Hasil perhitungan menunjukan bahwa hanya bangunan Masjid Al Balad yang mengarah ke Kota Mekah. Rata-rata besarnya penyimpangan arah kiblat bangunan masjid ke ka’bah adalah sebesar 150 1’ 0,365”. Terdapat beberapa faktor yang teridentifikasi secara visual dan korelasi dapat mempengaruhi nilai penyimpangan arah bangunan masjid tersebut, diantaranya yaitu arah kepadatan bangunan sebesar 27,688 % dan koefisien dasar bangunan masjid sebesar 14,001 %

Perbandingan Nilai Kedalaman Relatif Sungai Brantas Kabupaten Jombang dengan Perhitungan Algoritma Van Hengel and Spitzer Citra Sentinel-2 dan Digital Elevation Model (DEM)

Shallow water relative depth can be gained from the Digital Elevation Model (DEM). As science develops, methods are developed to gain the relative depth one is by processing the Sentinel-2 image using Van Hengel and Spitzer algorithm. The authors aim to compare the relative depth gained from the Sentinel-2 image using the Van Hengel and Spitzer algorithm to the relative depth gained from DEM. The data needed are orthorectified Sentinel-2 level 1C images downloaded from the Earth Explorer page and DEM downloaded from the Tanah Air page. Sentinel-2 image is then corrected atmospherically and radiometrically to get its radian value then processed using the Van Hengel and Spitzer algorithm. The sample points are spread at 25 meters intervals along the Jombang regency Brantas River. This study only compares the computational calculation therefore no field validation is carried out. Sentinel-2 Van Hengel and Spitzer provides an average relative depth of 16.35 m and DEM provides an average relative depth of 17.98 m with the determination coefficient (correlation value) of the two data is 6.52%. The low correlation is due to the high sediment content in the water column of Brantas River, causing the bias in the image.Kedalaman relatif perairan dangkal dapat diperoleh melalui Digital Elevation Model (DEM). Seiring berkembangnya sains, banyak metode dikembangkan untuk memperoleh nilai kedalaman relatif salah satunya dengan mengolah citra Sentinel-2 menggunakan algoritma Van Hengel and Spitzer. Penulis bertujuan untuk membandingkan nilai kedalaman relatif yang didapatkan dari pengolahan citra Sentinel-2 menggunakan algoritma Van Hengel and Spitzer dengan kedalaman relatif yang didapatkan melalui DEM. Data yang dibutuhkan pada penelitian ini adalah citra Sentinel-2 level 1C yang telah ter orthorektifikasi diunduh dari laman Earth Explorer dan DEM yang diunduh dari laman Tanah Air. Citra Sentinel-2 kemudian dikoreksi secara atmosferik dan radiometrik untuk mendapatkan nilai radiannya yang kemudian diolah dengan algoritma Van Hengel and Spitzer. Titik sampel disebar dengan interval 25 meter sepanjang sungai Brantas Kabupaten Jombang. Penelitian ini hanya membandingkan perhitungan secara komputasi sehingga tidak dilakukan validasi lapangan. Hasil dari pengolahan citra Sentinel-2 dengan algoritma Van Hengel and Spitzer memberikan rata-rata kedalaman relatif sebesar 16,35m dan rata-rata kedalaman relatif DEM yaitu sebesar 17,98m. Hasil perhitungan statistik menunjukkan nilai koefisien determinasi kedalaman relatif citra Sentinel-2 yang diolah menggunakan algoritma Van Hengel and Spitzer dengan DEM adalah sebesar 6,52%. Korelasi yang rendah tersebut diakibatkan tingginya kandungan sedimen dalam kolom air Sungai Brantas sehingga menimbulkan bias pada citra