Modelling Land Use/Land Cover Change of River Rwizi Catchment, South-Western Uganda Using GIS and Markov Chain Model

Analysis of catchment Land use/Land cover (LULC) change is a vital tool in ensuring sustainable catchment management. The study analyzed land use/land cover changes in the Rwizi catchment, south western Uganda from 1989-2019 and projected the trend by 2040. Landsat images, field observations, key informant interviews and focus group discussions were used to collect data. Changes in cropland, forestland, built up area, grazing land, wetland and open water bodies were analyzed in ArcGIS version 10.2.2 and ERDAS IMAGINE 14 software and a Markov chain model. All the LULC classes increased in area except grazing land. Forest land and builtup area between 2009-2019 increased by 370.03% and 229.53% respectively. Projections revealed an increase in forest land and builtup area by 2030 and only built up area by 2040. LULCC in the catchment results from population pressure, reduced soil fertility and high value of agricultural products.

Changes in snow cover extent in the Central Taurus Mountains from 1981 to 2021 in relation to temperature, precipitation, and atmospheric teleconnections

The snow cover over the Taurus Mountains affects water supply, agriculture, and hydropower generation in the region. In this study, we analyzed the monthly Snow Cover Extent(SCE) from November to April in the Central Taurus Mountains(Bolkar, Aladaglar, Tahtali and Binboga Mountains) from 1981 to 2021. Linear trends of snow cover season(November to April) over the last 41 years showed decreases in SCE primarily at lower elevations. The downward trend in SCE was found to be more pronounced and statistically significant for only November and March. SCE in the Central Taurus Mountains has declined about-6.3% per decade for 2500-3000 m in November and about-6.0% per decade for 1000-1500 m and 3000+ m in March over the last 41 years. The loss of SCE has become evident since the 2000s, and the lowest negative anomalies in SCE have been observed in 2014, 2001, and 2007 in the last 41 years, which are consistent with an increase in air temperature and decreased precipitation. SCE was correlated with both mean temperature and precipitation, with temperature having a greater relative importance at all elevated gradients. Results showed that there is a strong linear relationship between SCE and the mean air temperature(r =-0.80) and precipitation(r = 0.44) for all elevated gradients during the snow season. The Arctic Oscillation(AO), the North Atlantic Oscillation(NAO), and the Mediterranean Oscillation(MO) winter indices were used to explain the year-to-year variability in SCE over the Central Taurus Mountains. The results showed that the inter-annual variability observed in the winter SCE on the Central Taurus Mountains was positively correlated with the phases of the winter AO, NAO and MO, especially below 2000 m elevation.

Geographical Information System-Based Assessment of Ecological Security in Changbai Mountain Region

Ecological security defined as the creation of a condition where the physical surroundings of a community provide for the needs of its inhabitants without diminishing its natural stock,which is important for regional security and social stability.In recent years,land use patterns in the Changbai Mountain region have changed significantly with intensive human activities,and consequently led to increasing problems in regional ecological security.Based on the Pressure-State-Impact-Response(PSIR) model and the mathematical method of catastrophe progression supported by geographical information system(GIS),the ecological security situation of the study area under land use and cover change(LUCC) was evaluated.The results indicated that the ecological security in Changbai Mountain region varied nonlinearly,which got better from 1990 to 2000 but became worse from 2000 to 2007,the ecological security levels in Changbai Mountain region were mainly medium and medium to low during the past 17 years,with higher values of Ecological Security Index(ESI) in the central region and lower values in the east and west,the ecological security situation was more serious in the settlements and river valleys,where the LUCC was most remarkable.

Assessment of Agricultural Drought Risk in the Sichuan Basin Based on Information Diffusion Theory

Based on data of agricultural drought situation and sown area of main crops in each county or district of the Sichuan Basin, the spatial distribution and probability of agricultural drought risk at different risk levels were studied using normal information diffusion method, and the risk zoning was carried out. The results showed that normal information diffusion method could fit the distribution of agricultural drought risk in the Sichuan Basin. By comparison with the end of the 20^th century, agricultural drought risk in Meishan, Chongqing City and so on increased at the beginning of the 21^st century when x1≥ 10% or x1≥40%. Agricultural drought risk was low in the west of the Sichuan Basin, which was related to rich precipitation here, but it was high in Bazhong, Zhongjiang, Luxian and so forth. The risk zoning results can provide scientific references for disaster prevention and emergency management of government.

Using Geospatial Information Component to Monitor the Watersheds along the Densu Basin in Ghana

The Densu basin is a coastal river catchment in southern Ghana and a typical rural community like all other rural settlements in Ghana. It is the only basin amongst 43 other basins of the country that supplies water to two regional capitals of Ghana, namely, the capital city of Ghana, Accra and Eastern regional capital, Koforidua. The qualities of these water resources vary naturally and widely depending on climate, season, and the geology of the bedrock, as well as anthropogenic activities. The primary aim of this research is to determine data requirements for efficient and cost-effective development of a Geographic Information System (GIS) to map and detect the extent of the sources of the watersheds and how to protect the environment for continuous supply of water. Among the Nine catchment areas, only one catchment WSA_05 (Koforidua Township) was determined to have a very high risk of being vulnerable and therefore required urgency to protect environment for continuous supply of water. Four catchment areas WSA_02 (Weija Dam), WSA_03 (Apedwa-Asafo), WSA_06 (Suhum) and WSA_09 (New Tafo) were determined to have a high risk of being affected and therefore there was the need to protect the environment for continuous supply of water. Ghana as a country will have to take a responsible step in protecting its water body and its environment to enable continuous and sustainable supply of water to its citizens. This study therefore reveals the state of the water users and how urgent it environment needs to be protected.

地质灾害易发性评价因子分级的AIFFC算法优化

针对地质灾害易发性评价因子分级数不确定的问题,引入自适应膨胀因子模糊覆盖分级方法(fuzzy cover approach for clustering based on adaptive inflation factor,AIFFC)对易发性评价因子分级进行优化。以湖南省湘乡市为研究区,提取了坡度、坡向、高程、年平均降雨量、归一化植被指数、道路、断层、岩性和土地利用9类评价因子,运用AIFFC及自然断点法(natural breakpoint classification,NBC)对连续型因子进行分级,并分别代入加权信息量模型和随机森林模型,获取研究区易发性区划图。采用单因子分级结果精度、灾积比分析和易发性分区结果对AIFFC分级法的优越性进行检验,结果表明:各因子采用AIFFC算法分级的AUC值均高于自然断点法;基于AIFFC的随机森林模型及加权信息量模型的高易发区灾积比分别提升了56.3%、74.6%,低易发区灾积比分别降低了48%、58.1%,AUC值分别提升了7.6%、2.7%。采用AIFFC分级方法优化了地质灾害易发性评价因子分级,显著提高了地质灾害易发性评价的合理性。

2000-2020年吉林省西部地区碳储量时空变化研究

基于ArcGIS及InVEST模型计算吉林省西部地区碳储量,以其评估单元为植被覆盖类型,计算地上部分碳、地下部分碳、土壤碳、死亡有机碳四种基本碳库。对比不同年份,即2000-2020年吉林省西部地区碳储量时间变化与空间变化特征,通过对吉林省西部地区碳储量的集中程度、变化程度和变化趋势的分析,以及该变化与西部地区生态环境变化之间的联系,总结变化原因。结果表明:从整体上看,白城地区碳储量有所增长,松原地区有所下降;从各个县、市上看,大安市2020年碳储量增加幅度最大,而松原市减少幅度最大。

融合GPU的拟单层覆盖近似集计算方法

拟单层覆盖粗糙集是一种匹配集值信息系统且有高质量和高效率的粗糙集模型。拟单层覆盖近似集的计算过程中存在大量计算密集且逻辑简单的运算,为此,提出拟单层覆盖近似集的矩阵化表示方法,以利用图形处理器(GPU)强大的计算性能加速计算过程。为了实现这一目标,使用布尔矩阵表示拟单层覆盖近似空间中的元素,引入与集合运算对应的布尔矩阵算子,提出拟单层覆盖粗糙近似集(DE、DA、DE0与DA0)的矩阵表示,并设计矩阵化拟单层覆盖近似集算法(M_SMC)。同时,相应的定理证明了拟单层覆盖近似集的矩阵表示形式与原始定义的等价性。然而,M_SMC运行过程中出现了矩阵存储和计算步骤的内存消耗过多问题。为了将算法部署到显存有限的GPU上,优化矩阵存储和计算步骤,提出分批处理的矩阵化拟单层覆盖近似集算法(BM_SMC)。在10个数据集上的实验结果表明,融合GPU的BM_SMC算法与单纯使用中央处理器(CPU)的BM_SMC算法相比计算效率提高2.16~11.3倍,BM_SMC算法可以在有限的存储空间条件下充分利用GPU,能够有效地提高拟单层覆盖近似集的计算效率。

基于集覆盖理论的覆盖信息系统属性约简方法

针对覆盖信息系统属性约简问题,提出基于集覆盖理论的覆盖信息系统属性约简方法。首先,构造覆盖信息系统的相关矩阵,通过相关矩阵诱导出覆盖信息系统的集覆盖模型,并探讨了覆盖信息系统与其诱导的集覆盖模型之间的联系,发现集覆盖模型的一个极小覆盖恰是原覆盖信息系统的一个属性约简集,从而可以将求解覆盖信息系统的属性约简问题转化为求解对应集覆盖模型的极小集覆盖问题。其次,利用集覆盖启发式算法(set covering heuristic algorithm,SCHA)在解决集覆盖问题上具有更高的精度和更好的性能,给出了基于SCHA的覆盖信息系统属性约简的求解步骤及算法。最后,通过实例验证了所提方法的可行性和有效性。

基于多季相分形特征的Landsat 8 OLI影像耕地信息提取方法

利用遥感技术快速准确地提取耕地信息是耕地保护的关键环节。以山东省商河县为例,提出了一种基于多季相分形特征的Landsat 8 OLI影像耕地信息提取方法。首先采用毯子覆盖法计算多季相遥感影像每个像元的上分形信号和下分形信号,对比分析耕地和其他土地利用类型的分形特征,选取上分形信号的第3尺度作为特征尺度,提取商河县耕地空间分布特征;其次采用同时期的土地利用矢量数据、Esri land cover数据和统计数据进行耕地信息提取精度评价;最后分别设置多季相分形提取与单季相分形提取、现有土地利用数据产品的对比实验,并基于点位匹配度和面积匹配度进行评价。结果表明:多季相数据更能反映农作物生长的复杂性,有助于提高耕地信息的提取精度;不同土地利用类型在不同分形尺度的信号值各不相同,分形特征可以在不同尺度上清晰地刻画出不同土地利用类型的分异性;基于矢量数据和Esri land cover数据评价的多季相分形特征耕地提取点位匹配度为87.13%和89.83%,面积匹配度为99.73%和97.91%,均比单季相分形提取结果精度高;综合考虑点位匹配度、面积匹配度和空间分布特征,研发方法能有效区分耕地和其他土地利用类型,提取结果更优,且与统计数据有更高的一致性。该方法可准确提取耕地信息,为耕地的动态监测和损害评估提供技术支撑。

涉电信诈骗资金交易黄金行为的司法认定——以深圳黄金公司涉嫌掩饰、隐瞒犯罪所得罪案例为视角

黄金公司以涉诈资金交易黄金行为应当适用“综合”认定规则适用罪名。在客观上,“涉诈资金”与“交易黄金”要素不仅符合帮助信息网络犯罪活动罪“提供支付结算功能”,还符合掩饰、隐瞒犯罪所得、犯罪所得收益罪“以其他方式掩饰、隐瞒”。在主观上,黄金公司只要行为人认识到他人实施的是刑法分则规定的行为类型,就已经满足帮助信息网络犯罪活动罪与掩饰、隐瞒犯罪所得、犯罪所得收益罪的“明知”要素。在完善“竞合说”的基础上,提出上游既遂犯罪前、既遂后仅提供账户成立帮助信息网络犯罪活动罪;既遂后提供账户并实施转账、取现等行为二罪想象竞合的“综合”认定规则,同时,判断犯罪数额,应当以狭义和广义的“涉诈资金”概念区分二罪的刑事责任。

粤北典型山区城市土地利用时空动态变化分析

根据《土地调查条例》规定,国家根据国民经济和社会发展需要,每10年进行一次土地调查。迄今为止,共开展了3次全国国土调查工作。在国土调查基础上进而分析土地利用时空动态变化,对利用与科学管理国土资源具有重要意义。本文以粤北典型山区城市连州为研究区域,利用2009年、2019年两期Landsat遥感影像,通过土地利用动态度和空间自相关两大分析手段,剖析了粤北典型山区城市土地利用格局和土地覆盖变化速率和程度。研究结果表明:10年间,林地、耕地是研究区土地利用时空动态变化的主要类型;研究区土地利用强度较低且变化不明显,空间上具有一定的分异规律。

韩江中上游地区的崩岗分布特征

选取韩江中上游地区2016—2022年的Sentinel-1/2卫星星座遥感影像和其他辅助数据,基于机器学习方法进行区域尺度的崩岗识别和崩岗影响因子测度。结果表明:1)分类模型的总体精度达到84%,Kappa系数为0.8。其中,崩岗识别的用户精度和生产者精度都超过95%,且其FScore为0.97。2)截至2022年,韩江中上游地区的崩岗侵蚀面积共有435.5 km^(2),各县(市、区)崩岗侵蚀面积差异明显,年变化趋势不一。其中,五华县崩岗侵蚀面积最多(199.2 km^(2)),其年平均变化率为16.29 km^(2)/a。梅江区崩岗侵蚀面积最少(1.6 km^(2)),其年平均变化率为0.18 km^(2)/a。3)韩江中上游地区崩岗发生概率与高程、坡度、植被覆盖、地质类型、人口密度、大气压、降雨量、经向风速、纬向风速和风速等10个因素存在显著相关性(P<0.001)。在一定的变化范围内,高程、坡度、地质类型、大气压、经向风速、纬向风速和风速对研究区崩岗发生为正向影响,植被覆盖、人口密度和降雨量对崩岗发生为负向影响。

计及FTU信息畸变情况下基于覆盖集理论的配电网故障定位

配电网故障后,馈线终端装置传输的故障信息可能会发生畸变,为了提升基于FTU的配电网故障定位的容错性,考虑畸变故障信息对故障区段定位的影响,对其分类为正常、误判、漏判和影响四种类型;其次,为了消除畸变信息带来的影响,基于覆盖集理论,计及FTU故障信息与保护出口信息的内在逻辑联系,建立配电网故障定位的新目标函数,引入不冗余指标和最小性指标两个约束条件,分别用以处理故障定位的信息畸变问题和故障定位准确性问题;最后,采用遗传算法,对故障定位的配电网含分布式电源和不含分布式电源两种情况展开论述,通过两个算例证明:(1)不同的故障信息畸变对配电网故障定位的影响;(2)基于覆盖集理论的改进目标函数在配电网故障定位中的精度和容错性优势。

Accuracy Assessment of Land Use/Land Cover Classification Using Remote Sensing and GIS

Remote sensing is one of the tool which is very important for the production of Land use and land cover maps through a process called image classification. For the image classification process to be successfully, several factors should be considered including availability of quality Landsat imagery and secondary data, a precise classification process and user’s experiences and expertise of the procedures. The objective of this research was to classify and map land-use/land-cover of the study area using remote sensing and Geospatial Information System (GIS) techniques. This research includes two sections (1) Landuse/Landcover (LULC) classification and (2) accuracy assessment. In this study supervised classification was performed using Non Parametric Rule. The major LULC classified were agriculture (65.0%), water body (4.0%), and built up areas (18.3%), mixed forest (5.2%), shrubs (7.0%), and Barren/bare land (0.5%). The study had an overall classification accuracy of 81.7% and kappa coefficient (K) of 0.722. The kappa coefficient is rated as substantial and hence the classified image found to be fit for further research. This study present essential source of information whereby planners and decision makers can use to sustainably plan the environment.

Land Use and Land Cover Changes in Awash National Park, Ethiopia: Impact of Decentralization on the Use and Management of Resources

We analyzed the magnitude of land use land cover changes and identified drivers of those changes at Awash National Park, Ethiopia, using aerial photographs, satellite images and field observation. Scattered bushland—the most important habitat for the wild animals, declined drastically. Areas under grassland, farmland or open land increased over the study period. Policy and park border demarcation issues were identified as drivers of change before 1995 (before decentralization), whereas livestock grazing was indicated to be the leading driver of change after 1995. Major events and causes that largely explained these changes include immigration of the Ittu community, land tenure system, drought, poaching, use policy issues and regional economic and infrastructural development. Our study reveals that the sustainability of the park calls for an immediate action to reduce the ever increasing human and livestock pressure on park resources.

Land Use/Land Cover Changes of Ago-Owu Forest Reserve, Osun State, Nigeria Using Remote Sensing Techniques

Remote sensing (RS) and GIS are important methods for land use assessment and land cover transition. In this study, land use/land cover changes in the Ago-Owu Forest Reserve, Osun State, Nigeria have been assessed. Landsat 5 TM, Landsat 7 ETM+ and Landsat 8 OLI were acquired for 1986, 2002 and 2017 respectively. The three scenes corresponded to path 190 and row 055 of WRS-2 (Worldwide Reference System). The processing of the imagery was preceded by the clipping of the study area from the satellite image. The boundary of the reserve was carefully digitized and used to clip the imagery to produce an image map of the forest reserve. Using the supervised image classification procedure, training sites were used to produce land use/land cover maps. The same classification scheme was used for the 1986, 2002 and 2017 images to facilitate the detection of change. The differences in the area covered by the different polygons between the three sets of images were measured in km2. The results show that during 1986 and 2017, there is a dramatic increase of build-up areas with a change of 55.65 km2 and sparse vegetation (farmland and grassland) with a change of 53.97 km2, while a dramatic decrease of dense vegetation (forest areas) with a change of 109.61 km2. The consequence of these results is that over the years, the population of people living in the forest reserve has increased and many of them are engaged in farming, leading to an increase in farmland. In addition, logging activities continued unabated in the forest reserve, as demonstrated by a sharp increase in the deforested area within the reserve. The maps produced in this study will serve as a planning tool for the Osun State Forestry Department to plan reforestation activities for the forest reserve.

Review of studies on land use and land cover change in Nepal

Land use and land cover(LULC) in Nepal has undergone constant change over the past few decades due to major changes caused by anthropogenic and natural factors and their impacts on the national and regional environment and climate.This comprehensive review of past and present studies of land use and land cover change(LUCC) in Nepal concentrates on cropland, grassland, forest, snow/glacier cover and urban areas. While most small area studies have gathered data from different sources and research over a short period, across large areas most historical studies have been based on aerial photographs such as the Land Resource Mapping Project in 1986. The recent trend in studies in Nepal is to focus on new concepts and techniques to analyze LULC status on the basis of satellite imagery, with the help of geographic information system and remote sensing tools. Studies based on historical documents, and historical and recent spatial data on LULC, have clearly shown an increase in cropland areas in Nepal,and present results indicating different rates and magnitudes. A decrease in forest and snow/glacier coverage is reported in most studies. Little information is available on grassland and urban areas from past research. The unprecedented rate of urbanization in Nepal has led to significant urban land changes over the past 30 years. Meanwhile, long term historical LUCC research in Nepal is required for extensive work on spatially explicit reconstructions on the basis of historical and primary data collection, including LULC archives and drivers for future change.

Assessing the Impacts of Land Use and Land Cover Changes on Hydrology of the Mbarali River Sub-Catchment. The Case of Upper Great Ruaha Sub-Basin, Tanzania

Intensification of agricultural land use and population growth from 1990-2017 has caused changes in land cover and land use of the Mbarali River sub-catchment which is located in the Upper Great Ruaha Sub basin, Tanzania. This has affected the magnitude of the surface runoff, total water yield and the groundwater flow. This study assesses the impacts of the land cover and land use changes on the stream flows and hydrological water balance components (surface runoff, water yield, percolation and actual evapotranspiration). The land use and land cover (LULC) maps for three window period snapshots, 1990, 2006 and 2017 were created from Landsat TM and OLI_TIRS with the help of QGIS version 2.6. Supervised classification was used to generate LULC maps using the Maximum Likelihood Algorithm and Kappa statistics for assessment of accuracy. SWAT was set up and run to simulate stream flows and hydrological water balance components. The assessment of the impacts of land use and land cover changes on stream flows and hydrological water balance component was performed by comparing hydrological parameters simulated by SWAT using land use scenarios of 2006 and 2017 against the baseline land use scenario of 1990. Accuracy of LULC classification was good with Kappa statistics ranging between 0.9 and 0.99. There was a drastic increase in areal coverage of cultivated land, for periods 1990-2006 (5.84%) and 2006-2017 (12.05%) compared to other LULC. During 2006 and 2017 surface runoff increased by 4% and 9% respectively;however, water yield increased by only 0.5% compared to 1990 baseline period. This was attributed to increased proportion of cultivated land in the sub-catchment which has a high curve number (59.60) that indicates a higher runoff response and low infiltration rate.

Evaluation of Land Use &Land Cover Change Using Multi-Temporal Landsat Imagery: A Case Study Sulaimaniyah Governorate, Iraq

Land use & land cover change detection in rapid growth urbanized area have been studied by many researchers and there are many works on this topic. Commonly, settlement sprawl in area depends on many factors such as eco-nomic prosperity and population growth. Iraq is one of the countries which witnessed rapid development in the settlement area. Remote sensing and geographic information system (GIS) are analytical software technologies to evaluate this familiar worldwide phenomenon. This study illustrates settlement development in Sulaimaniyah Governorate from 2001 to 2017 using Landsat satellite imageries of different periods. All images had been classified using remote sensing software in order to proceed powerful mapping of land use classification. Maximum likelihood method is used in the accurately extracted solution information from geospatial imagery. Landsat images from the study area were categorized into four different classes. These are: forest, vegetation, soil, and settlement. Change detection analysis results illustrate that in the face of an explosive demographic shift in the settlement area where the record + 8.99 percent which is equivalent to 51.80 Km2 over a 16-year period and settlement area increasing from 3.87 percent in 2001 to 12.86 percent in 2017. Accuracy assessment model was used to evaluate (LULC) classified images. Accuracy results show an overall accuracy of 78.83% to 90.09% from 2001 to 2017 respectively while convincing results of Kappa coefficient given between substantial and almost perfect agreements. This study will help decision-makers in urban plan for future city development.