Penelitian analisis perubahan penggunaan lahan telah dilakukan menggunakan metode penginderaan jauh (inderaja) dan sistem informasi geografis (SIG). Identifikasi peta perubahan penggunaan lahan dilakukan dengan menggunakan proses tumpang susun peta penggunaan lahan tahun 1990 (hasil digitasi skala 1:50.000) dan peta penggunaan lahan tahun 1997 hasil interpretasi citra Landsat TM (Thematic Mapper) tahun 1997 dengan koordinat UTM (Universal Transverse Mercator). Perbaikan kontras citra melalui perataan histogram dilakukan dengan teknik klasifikasi terawasi yang terbagi menjadi 7 (tujuh) klas (sawah, perkampungan, tegalan, industri, tambak, lapangan olah raga dan semak). Analisis perubahan penggunaan lahan dan tingkat pencemaran air sungai BOD (Biological Oxygen Demand), COD (Chemical Oxygen Demand) dan TSS (Total Suspended Solid) dilakukan dalam sistim informasi geografis hingga diperoleh database dengan format link spasial dan tabular. Perubahan penggunaan lahan dianalisis berdasarkan pembagian segmen mengacu arah kontur sepanjang Kali Surabaya. Hasil analisis memperlihatkan perubahan penggunaan lahan pada tahun 1990-1997 yakni sawah berkurang 5,72 %, perkampungan bertambah 15,16 %, tegalan bertambah 0,54 %, tambak berkurang 9,67 %, industri bertambah 36,67 % dan semak berkurang 26,67 %. Hasil analisis tingkat pencemaran air dengan regresi linier berganda menunjukkan BOD (koefisien determinan 56 %) dan TSS (koefisien determinan 65 %) masih dipengaruhi oleh perubahan penggunaan lahan, tidak demikian halnya dengan COD (koefisien determinan 24 %).

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Application of Remote Sensing and Geographic Information System Methods for Land Using Difference. Land using difference analysis has been done using remote sensing and Geographic Information System (GIS) methods. Identification of land using difference was conducted using map overlaying process of 1990s (digitized scalling 1:50.000) and 1997s land using map (interpreted from Landsat TM (Thematic Mapper) Image 1997) with UTM (Universal Transverse Mercator) coordinate. Image enhancement was done through histogram equalization with supervised classification devided into 7 classes: rice field, settlement, dry field, industry, pond, sport field and bush. Land using difference and river pollution BOD (Biological Oxygen Demand), COD (Chemical Oxygen Demand) and TSS (Total Suspended Solid) analysis were done through GIS to get database in spasial link and tabular format. Land using difference was done based on division segment of Kali Surabaya contour as reference. The result shows that there were changes on land using from 1990 until 1997 that rice field reduced by 5.72 %; settlement increased by 15,16 %; dry field increased by 0.54 %; industry increased by 36.67 % and bush reduced by 26.67 %. Water pollution analysis results which was done using multiple linier regression show both BOD (determinant coefficient 56 %) and TSS (determinant coefficient 65 %) are affected by difference in land using, but COD (determinant coefficient 24 %) is not affected.