Analisis Perubahan Garis Pantai Krematorium Pekalongan Jawa Tengah Menggunakan QGIS & DSAS

Perubahan morfologi garis pantai merupakan proses dinamis yang dipengaruhi oleh interaksi faktor hidrodinamika alami, seperti pasang surut, gelombang, dan sedimentasi, serta aktivitas antropogenik berupa konversi lahan, reklamasi, dan pembangunan infrastruktur pesisir. Wilayah pesisir Kota Pekalongan, khususnya kawasan Pantai Informasi Mangrove (PIM) dan Pantai Krematorium Pekalongan, dalam beberapa dekade terakhir mengalami abrasi yang semakin intensif sehingga berdampak pada kerentanan sosial dan degradasi lingkungan pesisir. Penelitian ini bertujuan menganalisis perubahan garis pantai secara spasial dan temporal menggunakan citra satelit Landsat multitemporal tahun 1995, 2005, 2015, dan 2025 yang diolah dengan QGIS dan dianalisis menggunakan Digital Shoreline Analysis System (DSAS). Garis pantai diekstraksi menggunakan Normalized Difference Water Index (NDWI), kemudian dianalisis berdasarkan parameter End Point Rate (EPR), Linear Regression Rate (LRR), Net Shoreline Movement (NSM), Shoreline Change Envelope (SCE), dan Weighted Linear Regression (WLR) dengan mempertimbangkan nilai uncertainty citra. Hasil analisis menunjukkan bahwa wilayah penelitian didominasi oleh proses abrasi dengan nilai rata-rata EPR -4,47 m/tahun, LRR -4,44 m/tahun, dan WLR -4,47 m/tahun, serta pergeseran kumulatif garis pantai (NSM) rata-rata -134,78 m. Nilai SCE rata-rata sebesar 164,98 m menunjukkan tingginya dinamika perubahan garis pantai secara spasial, sementara nilai uncertainty sebesar 33,81-34,58 m menandakan bahwa tren perubahan yang dihasilkan tetap konsisten meskipun terdapat keterbatasan resolusi spasial citra Landsat. Studi ini diharapkan dapat menjadi dasar ilmiah bagi perencanaan dan pengelolaan wilayah pesisir Kota Pekalongan secara adaptif dan berkelanjutan.

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Coastal morphology change is a dynamic process influenced by the interaction of natural hydrodynamic factors, such as tides, waves, and sedimentation, as well as anthropogenic activities including land-use conversion, reclamation, and coastal infrastructure development. The coastal area of Pekalongan City, particularly the Pantai Informasi Mangrove (PIM) and Pantai Krematorium Pekalongan, has experienced increasingly intensive shoreline abrasion over recent decades, leading to heightened social vulnerability and environmental degradation. This study aims to analyze spatial and temporal shoreline changes using multitemporal Landsat satellite imagery from 1995, 2005, 2015, and 2025, processed with QGIS and analyzed using the Digital Shoreline Analysis System (DSAS). Shoreline extraction was conducted using the Normalized Difference Water Index (NDWI), followed by analysis based on the End Point Rate (EPR), Linear Regression Rate (LRR), Net Shoreline Movement (NSM), Shoreline Change Envelope (SCE), and Weighted Linear Regression (WLR), while accounting for shoreline uncertainty. The results indicate that the study area is predominantly affected by abrasion, as shown by average EPR, LRR, and WLR values of -4.47 m/year, -4.44 m/year, and -4.47 m/year, respectively, with an average cumulative shoreline retreat (NSM) of -134.78 m. An average SCE value of 164.98 m reflects high spatial shoreline variability, while shoreline uncertainty values ranging from 33.81 to 34.58 m indicate that the identified shoreline change trends remain consistent despite the moderate spatial resolution of Landsat imagery. This study is expected to provide a scientific basis for adaptive and sustainable coastal management in Pekalongan City.