For decades, Africa has undergone many crisis, affecting economy, climate, food, politics as well as society with irreparable consequences on the environment. The protection of the latter, being one of the cornerstone...For decades, Africa has undergone many crisis, affecting economy, climate, food, politics as well as society with irreparable consequences on the environment. The protection of the latter, being one of the cornerstones of sustainable development, is only possible if it＇s based on a reliable and rigorous diagnosis and inventory. This study suggests a method to characterize natural resources, in particular agricultural ones, by showing their landscape context. In this perspective and in the absence of any pre-existing mapping, as it is often the case in Africa, this work provides a simple and reproducible approach that merely uses Landsat Thematic Mapper （TM） （free） images, with the only constraint of the cross-checking of several images at different times of the plant cycle.展开更多
Sri Lanka is experiencing speedy urbanization by converting the agriculture land and other natural land cover into built-up land. The urban population of Sri Lanka is expected to reach to 60% by 2030 from 14% in 2010....Sri Lanka is experiencing speedy urbanization by converting the agriculture land and other natural land cover into built-up land. The urban population of Sri Lanka is expected to reach to 60% by 2030 from 14% in 2010. The rapid growth in urban population and urban areas in Sri Lanka may cause serious socioeconomic disparities, if they are not handled properly. Thus, planners in Sri Lanka are in need of information about past and future urban growth patterns to plan a better and sustainable urban future for Sri Lanka. In this paper, we analyzed the characteristics of past land use and land cover trends in Matara City of Sri Lanka from 1980 to 2010 to assess the historic urban dynamics. The land use change detection analysis based on remote sensing datasets reveal that the conversion of homestead/garden and paddy into urban land is evident in Matara City. The historic urban trends are projected into the near future by using SLEUTH urban growth model to identify the hot spots of future urbanization and as well as the urban growth patterns in Matara City up to the basic administrative level, i.e., Grama Niladari Divisions(GND). The urban growth simulations for the year 2030 reveal that 29 GNDs out of 66 GNDs in Matara City will be totally converted into urban land. Whereas, 28 GNDs will have urban land cover from 75% to 99% by 2030. The urban growth simulations are further analyzed with respect to the proposed Matara city development plan by the Urban Development Authority(UDA) of Sri Lanka. The results show that the UDA's city development plan of Matara will soon be outpaced by rapid urbanization. Based on the calibration and validation results, the SLEUTH model proved to be a useful planning tool to understand the near future urbanization of Sri Lankan cities.展开更多
This article describes metrics in order to quantify landscape structure. Landscape metrics are offered and designed to be as versatile as possible using several programs. In this paper it is attempted to （a） collect...This article describes metrics in order to quantify landscape structure. Landscape metrics are offered and designed to be as versatile as possible using several programs. In this paper it is attempted to （a） collect all the metrics found in the literature, （b） classify them, and （c） evaluate them through their use. An extensive investigation of the literature has been performed. Small discussion of each metric is provided to its concept, definition, use, way of calculation and in some cases contribution to the sustainable development. The frequency of used papers per each index has been taken into account. The most used to the least used six metrics have the following order： Area/Density/Edge; Isolation Proximity; Diversity; Contagion Interspersion; Shape; Connectivity. Moreover, the frequency of used papers is divided into five groups, i.e. group A till group E. Concluding, it has been provided an explanation of the results regarding to the four indices of group A and two indices from the group B.展开更多
The current economic crisis has left numerous residential developments in the southeastern United States in various stages of construction. Many of them are currently graded and essentially abandoned, creating a major...The current economic crisis has left numerous residential developments in the southeastern United States in various stages of construction. Many of them are currently graded and essentially abandoned, creating a major source of sediment runoff to waterways. Residential development locations with significant bare soil areas were identified through classification of Landsat 5 TM satellite imagery and subsequently verified from high-resolution county aerial photographs. The revised universal soil loss equation (RUSLE) was used in a geographic information system (GIS) as a tool for prioritizing identified locations on the basis of potential soil loss assuming the worst case scenario of a completely unmaintained site. Initial GIS identification indicated 301 sites with a total bare soil area of 2 378 ha over three counties in Upstate South Carolina. A random sample of 153 sites was visited over 17 days and assessed using a mobile GIS, global positioning system (GPS), and digital camera for field validation. Results indicated that 78% (119) of the sites were classified correctly (residential construction sites in varying stages of completion); 88% of identified areas were less than 25% built compared to the previous year; 48% were categorized as moderate to severe problems. Abandoned and unfinished developments in Upstate South Carolina may represent a major source of sediment pollution to streams. Well-maintained erosion control devices may be useful in preventing offsite sedimentation.展开更多
文摘For decades, Africa has undergone many crisis, affecting economy, climate, food, politics as well as society with irreparable consequences on the environment. The protection of the latter, being one of the cornerstones of sustainable development, is only possible if it＇s based on a reliable and rigorous diagnosis and inventory. This study suggests a method to characterize natural resources, in particular agricultural ones, by showing their landscape context. In this perspective and in the absence of any pre-existing mapping, as it is often the case in Africa, this work provides a simple and reproducible approach that merely uses Landsat Thematic Mapper （TM） （free） images, with the only constraint of the cross-checking of several images at different times of the plant cycle.
文摘Sri Lanka is experiencing speedy urbanization by converting the agriculture land and other natural land cover into built-up land. The urban population of Sri Lanka is expected to reach to 60% by 2030 from 14% in 2010. The rapid growth in urban population and urban areas in Sri Lanka may cause serious socioeconomic disparities, if they are not handled properly. Thus, planners in Sri Lanka are in need of information about past and future urban growth patterns to plan a better and sustainable urban future for Sri Lanka. In this paper, we analyzed the characteristics of past land use and land cover trends in Matara City of Sri Lanka from 1980 to 2010 to assess the historic urban dynamics. The land use change detection analysis based on remote sensing datasets reveal that the conversion of homestead/garden and paddy into urban land is evident in Matara City. The historic urban trends are projected into the near future by using SLEUTH urban growth model to identify the hot spots of future urbanization and as well as the urban growth patterns in Matara City up to the basic administrative level, i.e., Grama Niladari Divisions(GND). The urban growth simulations for the year 2030 reveal that 29 GNDs out of 66 GNDs in Matara City will be totally converted into urban land. Whereas, 28 GNDs will have urban land cover from 75% to 99% by 2030. The urban growth simulations are further analyzed with respect to the proposed Matara city development plan by the Urban Development Authority(UDA) of Sri Lanka. The results show that the UDA's city development plan of Matara will soon be outpaced by rapid urbanization. Based on the calibration and validation results, the SLEUTH model proved to be a useful planning tool to understand the near future urbanization of Sri Lankan cities.
文摘This article describes metrics in order to quantify landscape structure. Landscape metrics are offered and designed to be as versatile as possible using several programs. In this paper it is attempted to （a） collect all the metrics found in the literature, （b） classify them, and （c） evaluate them through their use. An extensive investigation of the literature has been performed. Small discussion of each metric is provided to its concept, definition, use, way of calculation and in some cases contribution to the sustainable development. The frequency of used papers per each index has been taken into account. The most used to the least used six metrics have the following order： Area/Density/Edge; Isolation Proximity; Diversity; Contagion Interspersion; Shape; Connectivity. Moreover, the frequency of used papers is divided into five groups, i.e. group A till group E. Concluding, it has been provided an explanation of the results regarding to the four indices of group A and two indices from the group B.
基金Supported by the South Carolina Water Resources Centerthe Clemson University Public Service and Agriculture Next Generation Graduate Fellowship (PSA-NGGF), USATechnical Contribution No. 5903 of the Clemson University Experiment Station, USA
文摘The current economic crisis has left numerous residential developments in the southeastern United States in various stages of construction. Many of them are currently graded and essentially abandoned, creating a major source of sediment runoff to waterways. Residential development locations with significant bare soil areas were identified through classification of Landsat 5 TM satellite imagery and subsequently verified from high-resolution county aerial photographs. The revised universal soil loss equation (RUSLE) was used in a geographic information system (GIS) as a tool for prioritizing identified locations on the basis of potential soil loss assuming the worst case scenario of a completely unmaintained site. Initial GIS identification indicated 301 sites with a total bare soil area of 2 378 ha over three counties in Upstate South Carolina. A random sample of 153 sites was visited over 17 days and assessed using a mobile GIS, global positioning system (GPS), and digital camera for field validation. Results indicated that 78% (119) of the sites were classified correctly (residential construction sites in varying stages of completion); 88% of identified areas were less than 25% built compared to the previous year; 48% were categorized as moderate to severe problems. Abandoned and unfinished developments in Upstate South Carolina may represent a major source of sediment pollution to streams. Well-maintained erosion control devices may be useful in preventing offsite sedimentation.
