Inland freshwater lake wetlands play an important role in regional ecological balance. Hongze Lake is the fourth biggest freshwater lake in China. In the past three decades, there has been significant loss of freshwat...Inland freshwater lake wetlands play an important role in regional ecological balance. Hongze Lake is the fourth biggest freshwater lake in China. In the past three decades, there has been significant loss of freshwater wet- lands within the lake and at the mouths of neighboring rivers, due to disturbance, primarily from human activities. The main purpose of this paper was to explore a practical technology for differentiating wetlands effectively from upland types in close proximity to them. In the paper, an integrated method, which combined per-pixel and per-field classifi- cation, was used for mapping wetlands of Hongze Lake and their neighboring upland types. Firstly, Landsat ETM＋ imagery was segmented and classified by using spectral and textural features. Secondly, ETM＋ spectral bands, textural features derived from ETM＋ Pan imagery, relative relations between neighboring classes, shape fea^xes, and elevation were used in a decision tree classification. Thirdly, per-pixel classification results from the decision tree classifier were improved by using classification results from object-oriented classification as a context. The results show that the technology has not only overcome the salt-and-pepper effect commonly observed in the past studies, but also has im- proved the accuracy of identification by nearly 5%.展开更多
Lowland tropical forest in Peninsular Malaysia consist a valuable dipterocarp timber species. In fact, dipterocarp tree species growth well when the ecology is maintained and their growth are dependent on the micro cl...Lowland tropical forest in Peninsular Malaysia consist a valuable dipterocarp timber species. In fact, dipterocarp tree species growth well when the ecology is maintained and their growth are dependent on the micro climate and also affected by lithology types. This study was carried out to identify and map tree species dominancy by lithology types at Hulu Sedili Forest Reserve （HSFR） using Geographic Information System （GIS） technique. Different lithology type maps were derived namely Igneous, Sedimentary and Limestone. Through GIS operations tree species data collected from pre-felling inventory and ground survey were overlaid with lithology features. Results showed that at Sedimentary and Igneous types, the presence of dipterocarpaceae family is only 3.09%, and non-dipterocarpaceae family was 96.91%. Syzygium spp. （19.83%） was the most abundance in Igneous and Sedimentary. Meanwhile, Elateriospermum tapos （9.92%） and Lauraceae＇s family （7.22%） were found to be the most dominant species in Sedimentary types, Macaranga spp. （11.21%） and Elateriospermum tapos （11.02%） in igneous types. However, a Limestone type was discarded from analysis due to unavailable pre-felling data. Thus, this study indicated that there was variation in species dominancy of different lithology types. On the other hand, GIS demonstrated its capability as a useful tool in identifying and maps the location of trees species based on lithology types.展开更多
基金Under the auspices of Natural Science Foundation of Jiangsu Province (No. BK2008360)Foundamental Research Funds for the Central Universities (No. 2009B12714,2009B11714)
文摘Inland freshwater lake wetlands play an important role in regional ecological balance. Hongze Lake is the fourth biggest freshwater lake in China. In the past three decades, there has been significant loss of freshwater wet- lands within the lake and at the mouths of neighboring rivers, due to disturbance, primarily from human activities. The main purpose of this paper was to explore a practical technology for differentiating wetlands effectively from upland types in close proximity to them. In the paper, an integrated method, which combined per-pixel and per-field classifi- cation, was used for mapping wetlands of Hongze Lake and their neighboring upland types. Firstly, Landsat ETM＋ imagery was segmented and classified by using spectral and textural features. Secondly, ETM＋ spectral bands, textural features derived from ETM＋ Pan imagery, relative relations between neighboring classes, shape fea^xes, and elevation were used in a decision tree classification. Thirdly, per-pixel classification results from the decision tree classifier were improved by using classification results from object-oriented classification as a context. The results show that the technology has not only overcome the salt-and-pepper effect commonly observed in the past studies, but also has im- proved the accuracy of identification by nearly 5%.
文摘Lowland tropical forest in Peninsular Malaysia consist a valuable dipterocarp timber species. In fact, dipterocarp tree species growth well when the ecology is maintained and their growth are dependent on the micro climate and also affected by lithology types. This study was carried out to identify and map tree species dominancy by lithology types at Hulu Sedili Forest Reserve （HSFR） using Geographic Information System （GIS） technique. Different lithology type maps were derived namely Igneous, Sedimentary and Limestone. Through GIS operations tree species data collected from pre-felling inventory and ground survey were overlaid with lithology features. Results showed that at Sedimentary and Igneous types, the presence of dipterocarpaceae family is only 3.09%, and non-dipterocarpaceae family was 96.91%. Syzygium spp. （19.83%） was the most abundance in Igneous and Sedimentary. Meanwhile, Elateriospermum tapos （9.92%） and Lauraceae＇s family （7.22%） were found to be the most dominant species in Sedimentary types, Macaranga spp. （11.21%） and Elateriospermum tapos （11.02%） in igneous types. However, a Limestone type was discarded from analysis due to unavailable pre-felling data. Thus, this study indicated that there was variation in species dominancy of different lithology types. On the other hand, GIS demonstrated its capability as a useful tool in identifying and maps the location of trees species based on lithology types.
