Assessing the applicability of OpenStreetMap data to assist the validation of land use/land cover maps     

Cidália C. Fonte  Nuno Martinho 《International journal of geographical information science》2017,31(12):2382-2400

The validation of land use/land cover (LULC) maps is usually performed using a reference database consisting of a sample of points or regions to which the ‘real’ class is assigned. This assignment is usually performed by specialists using photointerpretation (PI) of high-resolution imagery and/or field visits, which are time consuming and expensive processes. The aim of this article is to assess if the data available in the collaborative project OpenStreetMap (OSM) may be used as a source of data to assist the creation of these reference databases, reducing the time spent and costs associated with their generation. For this aim, two case studies were used, where the validation of the Global Monitoring for Environment and Security Urban Atlas (UA) was performed. The used methodology requires the harmonization of the data available in OSM with the UA nomenclature, and the subsequent creation of a LULC map from the OSM data. This map was then compared to UA to assess the similarity of the regions mapped in both. To test the usefulness of OSM data to assess the accuracy of UA, a sample of points was created and two reference databases generated, one assigning the data extracted automatically from OSM to the points where these data were available, and PI for the remaining points, and the other using only PI. The accuracy assessment of UA for the two case studies was then made building confusion matrixes and computing accuracy indicators. The results showed that for the two study areas, only low percentages of points had to be photo interpreted in the first reference database (respectively, 12% and 2% for the two study areas), decreasing the work load considerably. The results obtained with both reference databases are comparable for level 1 classes. For level 2 classes, worse results were obtained for some classes, showing that the OSM data used are not enough to create reliable reference data.  相似文献   

中等传输距离下的无线功率传输链路第1部分:实现工作状态最优化     

Alessio De ANGELIS  Marco DIONIGI  Paolo CARBONE  Mauro MONGIARDO  车文荃  王清华  Franco MASTRI  Giuseppina MONTI 《南京气象学院学报》2017,9(1):64-72

中程无线功率传输（WPT）可以采用几种不同的方式实现,如通过电感或电容耦合、谐振或非谐振网络实现.本文主要研究了通过感应耦合谐振器实现的WPT链路,而且只着重研究了利用2个谐振器的链路（直接链路）并工作在主谐振频率下的情况.研究结果表明,当工作在主谐振频率下,可以根据网络参数来对传输效率或负载功率进行优化.  相似文献   

利用TRMM卫星分裂窗通道对东亚地区夏季降水判识方法的探索     

王天天  齐瑾 《气象与环境科学》2017,40(2):1-10

利用2005年9月东亚中低纬地区的63个时次的TRMM卫星资料,分析了降水云和非降水云的红外辐射特征。结果显示:10.8μm通道大部分非降水像元的亮温大于280 K,晴空像元的亮温更高;大部分降水像元的亮温小于280 K,降水越强亮温越低,强降水的亮温在260 K以下。非降水像元的分裂窗通道亮温差(BTD45)总的来说都高于1.5 K;降水像元的BTD45总的来说都小于3.0 K,强降水像元BTD45较低,一般在2.0 K以下。在此基础上,分析了中低纬度夏季6次的不同类型的大尺度短时强降水数据,得到了中低纬度夏季强降水过程中非降水云和降水云对应的红外辐射特征,并以此为依据,提出BTD45为3.0 K和10.8μm通道亮温260 K为降水识别阈值,二者结合,可以得到较好的降水判识结果。  相似文献   

黑龙江省穆棱市土地利用/覆被变化及热点分析   总被引：1，自引：0，他引：1  

高凤杰  马泉来  单培明  刘洋  郭欣欣  杨双  张志民 《地域研究与开发》2016,(4):126-130

土地利用/覆被变化及其过程特征是全球变化领域研究的重点和热点。运用地统计学和3S技术,对黑龙江省穆棱市1991—2001年和2001—2013年土地利用/覆被变化及其空间演变特征进行研究。结果表明:1991—2001年间,耕地是主要转入地类,增加232.25 km~2,林地作为最大转出地类,减少290.35 km~2,林地与耕地的转化在土地利用变化中占最大比例,其他用地均发生变化,但面积小且散乱,整体上该时期土地利用呈现出开发混乱、效率低下的特点;2001—2013年间,受还林还草的影响,耕地减少179.01 km~2,林地增加171.45 km~2,其中坡耕地的退出占较大比例,且分布面积广,该时段内土地利用结构得到优化;土地利用变化的热点区由2001年前的"两大一小"模式,演变为以市区和中心乡镇围成的重点区域;1991—2013年间研究区自然因子变化较小,土地利用/覆被变化主要受退耕还林等国家政策的主导。  相似文献   

Fast food and liquor store density,co-tenancy,and turnover: Vice store operations in Chicago, 1995–2008     

《Applied geography (Sevenoaks, England)》2016

Fast food restaurants and liquor stores—vice stores—have been shown to be more prevalent in predominantly Black and low income U.S. neighborhoods, and are associated with a number of health risks and social ills. The purpose of this study was to investigate in the City of Chicago vice store density and spatial distribution as a function of racial, socioeconomic, and other population characteristics; to examine spatial clustering among these outlets; and to study how store turnover follows population change over a 13-year period. We used spatial point process analysis to fit linear and non-linear models for the intensity function of stores. Spatial clustering was estimated using the K function. We found heterogeneous associations between stores and population characteristics, with the most consistent finding being a positive association between percent Black and liquor store exposure. A high degree of spatial clustering was evident, and liquor stores were more likely to stay in business over time than fast food restaurants. However, when liquor stores closed, they were more likely to be replaced by non-vice businesses. Results suggest that vice stores are associated with lower positions in racial and socioeconomic hierarchies, and this patterning is often durable over time.  相似文献   

Dehydration experiments on natural omphacites: qualitative and quantitative characterization by various spectroscopic methods   总被引：1，自引：0，他引：1  

M. Koch-Müller  I. Abs-Wurmbach  D. Rhede  V. Kahlenberg  S. Matsyuk 《Physics and Chemistry of Minerals》2007,34(9):663-678

A series of natural omphacites from a wide range of P, T occurrences were investigated by electron microprobe (EMP), infrared (IR)-, Mössbauer (MS)- and optical spectroscopy in the UV/VIS spectral range (UV/VIS), secondary ion mass spectrometry (SIMS) and single crystal structure refinement by X-ray diffraction (XRD) to study the influence of hydrogen loss on valence state and site occupancies of iron. In accordance with literature data we found Fe²⁺ at M1 as well as at M2, and in a first approach assigned Fe³⁺ to M1, as indicated by MS and XRD results. Hydrogen content of three of our omphacite samples were measured by SIMS. In combination with IR spectroscopy we determined an absorption coefficient: ε _i,tot = 65,000 ± 3,000 lmol_H2O ^?1 cm^?2. Using this new ε _i,tot value, we obtained water concentrations ranging from 60 to 700 ppm H₂O (by weight). Hydrogen loss was simulated by stepwise heating the most water rich samples in air up to 800°C. After heat treatment the samples were analyzed again by IR, MS, UV/VIS, and XRD. Depending on the type of the OH defect, the grade of dehydration with increasing temperature is significantly different. In samples relatively poor in Fe³⁺ (<0.1 Fe³⁺ pfu), hydrogen associated with vacancies at M2 (OH bands around 3,450 cm^?1) starts to leave the structure at about 550°C and is completely gone at 780°C. Hydrogen associated with Al³⁺ at the tetrahedral site (OH bands around 3,525 cm^?1, Koch-Müller et al., Am Mineral, 89:921–931, 2004) remains completely unaffected by heat treatment up to 700°C. But all hydrogen vanished at about 775°C. However, this is different for a more Fe³⁺-rich sample (0.2 Fe³⁺ pfu). Its IR spectrum is characterized by a very intense OH band at 3,515 cm^?1 plus shoulder at 3,450 cm^?1. We assign this intense high-energy band to vibrations of an OH dipole associated with Fe³⁺ at M1 and a vacancy either at M1 or M2. OH release during heating is positively correlated with decrease in Fe²⁺ and combined with increase in Fe³⁺. That dehydration is correlated with oxidation of Fe²⁺ is indirectly confirmed by annealing of one sample in a gas mixing furnace at 700°C under reducing conditions keeping almost constant OH^? content and giving no indication of Fe²⁺-oxidation. Obtained data indicate that in samples with a relatively high concentration of Fe²⁺ at M2 and low-water concentrations, i.e., at a ratio of Fe^{2+ M2}/H > 10 dehydration occurs by iron oxidation of Fe²⁺ exclusively at the M2 site following the reaction: \( {\left[ {{\text{Fe}}^{{{\text{2 + [ M2]}}}}{\text{OH}}^{ - } } \right]} = {\left[ {{\text{Fe}}^{{{\text{3 + [ M2]}}}} {\text{O}}^{{{\text{2}} - }} } \right]} + {\text{1/2}}\;{\text{H}}_{{\text{2}}} \uparrow . \) In samples having relatively low concentration of Fe²⁺ at M2 but high-water concentrations, i.e., ratio of Fe^{2+ M2}/H < 5.0 dehydration occurs through oxidation of Fe²⁺ at M1.  相似文献   

High stress late Maastrichtian – early Danian palaeoenvironment in the Neuquén Basin, Argentina     

G. Keller  T. Adatte  A.A. Tantawy  Z. Berner  W. Stinnesbeck  D. Stueben  H.A. Leanza 《Cretaceous Research》2007,28(6):939-960

During the late Maastrichtian to early Danian the Neuquén Basin of Argentina was adjacent to an active volcanic arc to the west and an extensive land area to the northeast. Mineralogical and geochemical studies of the Bajada del Jagüel in the Neuquén Basin indicate a generally warm climate with seasonal changes in humidity and an open seaway to the South Atlantic that maintained marine conditions. Biostratigraphic and quantitative foraminiferal and nannofossil analyses indicate that sediment deposition during the late Maastrichtian (zones CF4-CF2, N. frequens) occurred in relatively shallow middle neritic (100 m) depths with largely dysaerobic bottom waters (abundant low O₂ tolerant benthics) and fluctuating sea level. Calcareous nannofossils indicate a high stress marine environment dominated by Micula decussata. Planktic foraminifera mimic the post-K/T high stress environment with alternating blooms of the disaster opportunists Guembelitria and low oxygen tolerant Heterohelix groups, indicating nutrient-rich surface waters and an oxygen depleted water column. The high stress conditions were probably driven by high nutrient influx due to upwelling and terrestrial and volcanic influx. The K/T boundary is marked by an erosional surface that marks a hiatus at the base of a 15-25 cm thick volcaniclastic sandstone, which contains diverse planktic foraminiferal zone P1c assemblages and nannofossils of zone NP1b immediately above it. This indicates deposition of the sandstone occurred 500 ky after the K/T hiatus. No evidence of the Chicxulub impact or related tsunami deposition was detected.  相似文献   

城市复杂环境下GNSS/INS组合导航算法研究     

王富  韩保民  胡亮亮  孟昊  郭振华 《大地测量与地球动力学》2022,42(1):15-20

针对城市环境下GNSS车辆导航存在卫星信号易受影响的问题,利用GNSS/INS组合算法提高复杂环境下城市车辆定位性能。基于城市环境下实测GNSS数据评估分析定位结果,使用GNSS/INS组合的常规卡尔曼滤波算法实现卫星失锁区域导航。同时,提出一种基于新息的自适应卡尔曼滤波算法,可有效增强卫星数较少及信号干扰严重区域的车辆导航定位能力。该方法利用量测与预测的关系构造自适应因子,改善定位精度。结果表明,常规卡尔曼滤波可在20 s卫星信号失锁情况下保证亚m级导航精度,自适应卡尔曼滤波算法在卫星信号受到严重干扰时,其定位精度相比于常规卡尔曼滤波算法提高30%,可满足在城市复杂环境下的高精度、高可靠性车辆导航定位服务需求。  相似文献   

Population dynamics, socioeconomic change and land colonization in northern Jordan, with special reference to the Badia Research and Development Project area     

Andrew Millington  Salem al-Hussein  Roderic Dutton 《Applied geography (Sevenoaks, England)》1999,19(4):1059

The paper reports on preliminary observations from northern Jordan aimed at testing the view that people migrate from areas of relatively high potential for cultivation to the marginal semi-arid/arid frontier because of social differentiation, political factors or environmental constraints. Cultivated areas have been mapped from multi-date remotely sensed imagery, a typology of fields in the area has been constructed, and their dynamics between 1972 and 1992 analysed. In addition, semi-structured interviews with farmers attempted to understand the reasoning behind village growth, changing farming systems and cultivation practices. The findings are discussed in the context of the area's demography and national and regional shifts in economic policy.  相似文献   

The evolutionary status of HD 104237, ε Cha and HD 100546     

Shen Chuan-jian  Hu Jing-yao   《Chinese Astronomy and Astrophysics》1999,23(4):493-497

Using the new data from Hipparcos and the TD-1 UV data, we fix the positions of three objects, HD 104237, HD 100546 and ε Cha in the HR diagram and discuss their theoretical evolutionary status.  相似文献