author = "Almeida-Filho, Raimundo and Shimabukuro, Yosio Edemir",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)}",
                title = "Digital processing of a Landsat-TM time series for mapping and 
                         monitoring degraded areas caused by independent gold miners, 
                         Roraima State, Brazilian Amazon",
              journal = "Remote Sensing of Environment",
                 year = "2002",
               volume = "79",
               number = "1",
                pages = "42--50",
                month = "Jan.",
             keywords = "geologia, Amaz{\^o}nia (Regi{\~a}o), mapeador tem{\'a}tico 
                         (Landsat), an{\'a}lise de series temporais, mapeamento, 
                         monitoramento ambiental, exatid{\~a}o, degrada{\c{c}}{\~a}o, 
                         thematic mappers (Landsat), time series analysis, environmental 
                         monitoring, accuracy, degradation.",
             abstract = "A 12-year Landsat-Thematic Mapper (TM)time series (1987-1999) was 
                         used for mapping and monitoring evolution of degraded areas caused 
                         by independent miners ({"}garimpeiros{"})in the search for gold 
                         and diamond. Discrimination of target areas was achieved through 
                         third principal component images, due to their best enhancement of 
                         bare soil areas relative to the surrounding savanna vegetated 
                         terrain. A postclassification approach, based on image 
                         segmentation/region classification techniques, was used to map 
                         degraded areas. This procedure allowed to save time and to curtail 
                         inherent subjectivity commonly involved in visual interpretation, 
                         producing accurate land-cover change maps. According to these 
                         maps. degraded areas comprise 94.4 ha in 1987. 286.4 ha in 1991, 
                         and 404.4 ha in 1994. After {"}garimpeiros{"} abandoned the region 
                         sometime prior to 1994, vegetation soon started recovering mined 
                         areas as shown in images acquired in 1995, 1996, and 1999. 
                         According to these images, degraded areas decreased to 311.2, 
                         283.7, and 246.2 ha, respectively. Data also indicate that 
                         vegetation regrowth is faster near the border of degraded areas, 
                         and becomes slower to the center of these areas, where damage 
                         process is more intense. Based on the satellite images-derived 
                         regrowth rates. it is possible to infer that degraded areas would 
                         not be entirely recovered by vegetation by the year 2019.",
                  doi = "10.1016/S0034-4257(01)00237-1",
                  url = "http://dx.doi.org/10.1016/S0034-4257(01)00237-1",
                 issn = "0034-4257",
                label = "9896",
             language = "en",
           targetfile = "1-s2.0-S0034425701002371-main.pdf",
        urlaccessdate = "24 jan. 2021"