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1.
This study develops confidence intervals for estimates of inferred oil and gas reserves based on bootstrap procedures. Inferred reserves are expected additions to proved reserves in previously discovered conventional oil and gas fields. Estimates of inferred reserves accounted for 65% of the total oil and 34% of the total gas assessed in the U.S. Geological Survey's 1995 National Assessment of oil and gas in US onshore and State offshore areas. When the same computational methods used in the 1995 Assessment are applied to more recent data, the 80-year (from 1997 through 2076) inferred reserve estimates for pre-1997 discoveries located in the lower 48 onshore and state offshore areas amounted to a total of 39.7 billion barrels of oil (BBO) and 293 trillion cubic feet (TCF) of gas. The 90% confidence interval about the oil estimate derived from the bootstrap approach is 22.4 BBO to 69.5 BBO. The comparable 90% confidence interval for the inferred gas reserve estimate is 217 TCF to 413 TCF. The 90% confidence interval describes the uncertainty that should be attached to the estimates. It also provides a basis for developing scenarios to explore the implications for energy policy analysis. 相似文献
2.
《The Journal of geography》2012,111(6):217-225
Abstract This article situates geospatial technologies as a constructivist tool in the K-12 classroom and examines student experiences with real-time authentic geospatial data provided through a hybrid adventure learning environment. Qualitative data from seven student focus groups demonstrate the effectiveness of using real-time authentic data, peer collaboration, and geospatial technologies in learning geography. We conclude with recommendations about geospatial technology curricula, geospatial lesson design, providing preservice teachers with geographic technological pedagogical content knowledge, and encouraging further research to investigate the impact, affordances, and pedagogical implications of geospatial technologies and data in the K–12 classroom. 相似文献
3.
In this article we draw on the power of geographic information systems (GIS) to examine the progression of HIV/AIDS in Africa for the period from 1986 to 2003. We use GIS for two purposes: (1) to transform and interpolate a set of annual point-based HIV/AIDS rates into area data; and (2) to extract or “mine” annual HIV/AIDS prevalence rates from the interpolated area (country) level maps. Once the rates are extracted from the GIS analysis we then model and forecast them into the near future (i.e., 2004–2010) by using the UNAIDS Estimation and Projection Package (EPP) software. The article offers an alternative grounded in geospatial analysis for yielding estimates of HIV/AIDS rates in Africa. Using incomplete sets of data for the period from 1986 to 2003, mean HIV/AIDS rates are generated from spatially interpolated data and future trends are estimated. The results indicate that the HIV/AIDS epidemic for many countries in Africa has reached the saturation or maturity level as evidenced by the typical S-shaped curves in the trends over time. As a matter of fact, some countries have begun to experience a sustained decline in the rates (e.g., Uganda, Burundi, Rwanda, and Zimbabwe). 相似文献
4.
The scope of empirical environmental justice (EJ) research has expanded beyond hazards exposure to scrutinize social inequities in access to amenities, but no prior study has examined the EJ implications of public beach access. Furthermore, quantitative research on white privilege is very scarce. To address these knowledge gaps, our study examines racial/ethnic and socioeconomic inequities in access to public beaches in the Miami metropolitan statistical area, Florida. Public beach accessibility is modeled with an innovative geospatial approach that involves population weighted distances to beach access sites. To assess EJ implications of public beach access for various racial/ethnic and socioeconomically vulnerable groups, spatial regression models are estimated using census tract-level data. Results indicate that beaches are more accessible to neighborhoods with a higher proportion of non-Hispanic Whites, while neighborhoods with higher percentages of Hispanics and socioeconomically disadvantaged residents have limited access. This study demonstrates the importance of assessing white privilege and access to environmental amenities in EJ research to better understand social inequities. 相似文献
5.
基于Logit 模型的世界主要作物播种面积变化模拟 总被引：6，自引：1，他引：5
农作物播种面积动态变化因其重要性已经引起了国内外学者的广泛关注。从“人-地 关系”中人的角度出发, 利用多元Logit 模型初步建立了全球尺度的农作物播种面积变化模 拟系统, 分析研究了未来30 年内世界主要农作物播种面积变化的数量特征和空间格局。模型建立思路是: 作物播种面积变化是农户作物选择行为的直接结果, 而选择何种作物进行播种是由作物效用决定的。因此, 利用离散选择理论, 选择影响作物效用大小的主要解释变量建立效用函数, 动态模拟农户作物选择行为, 并得到这种选择行为所带来的农作物播种面积变 化的时空特征。模型建立后, 利用联合国粮农组织(FAO) 2001-2003 年统计数据和2001 年MODIS 全球土地覆盖数据产品对模型结果进行验证, 结果表明模型运行可靠, 和实际状况吻合较好, 可以应用于未来情景模拟分析。其后, 以5 年为步长, 模型对世界四大作物(水稻、玉米、小麦和大豆) 在2005-2035 年间的播种面积动态变化进行了模拟, 从全球作物总播种面 积变化差异、四大作物播种面积变化的区域差异和不同区域内四大作物播种面积变化差异等方面进行了分析研究, 结果表明: 不同作物播种面积变化的数量特征和空间格局是不相同的。 虽然目前模型还存在一些不确定性, 但仍然能够在一定程度上为理解现在和未来农业土地利用的复杂动态变化提供帮助, 模拟结果可为有关部门提供决策支持和信息服务。 相似文献
6.
Karst landscapes are important assets that provide a source of water, host rare and endangered biota, and serve as sites of significant human historical artifacts. Previous studies have attempted to ascertain the extent of anthropogenic disturbance within karst areas using various standardized methods. A common limitation of these earlier approaches included lack of assessment of spatial variability. This paper recognizes the importance of spatial heterogeneity by using a spatially-explicit calculation of the Karst Disturbance Index (KDI) in a Geographic Information System (GIS) and applying it to a sub-catchment of the Biosfera de la Reserva Selve el Ocote in Chiapas, Mexico. With a raster-based GIS approach, this particular application is the highest resolution spatial representation of the KDI ever undertaken. As the study area is in a developing country, much of the data required for applying the KDI were drawn from remotely sensed data. The final disturbance scores found low to moderate levels of disturbance indicative of lightly populated area. However, this particular study can serve as a benchmark for future applications of the KDI in the study area, as well as in other karst watersheds in developed or developing countries. With the potential of future development looming, land managers can use the zones of pristine-to low-levels of disturbance to begin monitoring programs and justify mitigation and land management decisions. 相似文献
7.
Marco P Maneta Purnendu N Singh Marcelo Torres Wesley W Wallender Stephen A Vosti Lineu N Rodrigues Luis H Bassoi Julie A Young 《Area》2009,41(1):94-106
Reducing poverty in rural areas of developing countries requires sustained and sustainable increases in agricultural water productivity. However, aside from traditional measures of precipitation, little is known about water available to farmers or how productively they use it. We present a crop-water productivity index (a ratio of the value of annual crop production to a dimensionless potential water availability index) for large water basins using readily available low-resolution data. The index is transferable, permits direct inter-basin comparisons, and is simple to calculate. We calculate the index for each municipality in the São Francisco river basin in Brazil. No clear patterns linking water availability and value of agricultural output are evident, even though clusters of municípios with high- and low-crop-water productivity emerge, and the former may be useful in guiding policies aimed at increasing water productivity. Finally, analyses of the effects of information uncertainty on the crop-water productivity index suggest that the returns to agricultural investments in certain places in the São Francisco river basin are more risky than others. Improvements in data quality and quantity can help refine estimates of the index and reduce their uncertainty. 相似文献
8.
低成本流域空间数据库建库研究——以滇池流域为例 总被引：1，自引：0，他引：1
李泠潞 《云南地理环境研究》2011,23(3):107-110
空间数据库在流域空间信息系统中占有十分重要的地位,是进行信息化流域管理的数据基础。以滇池流域为例,利用地理信息系统技术和计算机技术,采用一些公开免费的数据资源和软件平台,经过资料搜集、数据库建模、数据处理和数据录入,在很短时间内,迅速完成了滇池流域空间数据库的建立。该空间数据库具有成本低、实现快、更新简单等优点,能实现滇池流域地理空间数据的快速查询和结果展示、渲染,可满足市级环境管理工作的日常需求。 相似文献
9.
湖北省洪湖市作物播种面积的三种数据差异分析 总被引：1，自引：0，他引：1
遥感技术已被广泛应用于农情监测, 但作物面积信息的遥测结果常与国家有关部门编制的《农业统计资料》、《统计年鉴》等各类统计资料中记载的作物播种面积数据不一致。文章以湖北省洪湖市为研究对象, 以10 m 分辨率的SPOT 多光谱影像和地面样方调查数据等为主要信息源, 对研究区域内中稻播面的统计值与真实值以及遥测值之间的差异进行了分析。 结果显示该市2006 年中稻播面的遥测结果为58788.09 hm2, 高出统计值52.156%, 而统计值则明显小于真实的播面数据。造成这一现象的主要原因在于该市对中稻播面统计时使用的亩制计量单位(习惯亩) 与标准亩之间存在1.507 的换算比率。过去国家实行农业税收政策时地 方有关部门为逃避农业税而少报瞒报水稻种植面积等因素也在一定程度上导致了上述差异。 相似文献
10.
O. P. Ermolaev K. A. Mal’tsev S. S. Mukharamova S. V. Kharchenko E. A. Vedeneeva 《Geography and Natural Resources》2017,38(2):131-138
An analysis made of the worldwide existing geoinformation systems (HydroSHEDS, CCM, Ecrins, WBD, etc.) suggests that there are as yet no models of adequate quality for the basin boundaries of small rivers in the European part of Russia. For the territory of the European part of Russia with a total area of more than 4 mln. km2 the GIS technology tools were used to construct the electron vector map of river basins and their interbasin spaces. The map thus obtained displays the basins of first-order rivers for a given level of generalization (sc 1:1 000 000). The GMTED2010 model was used as the digital elevation model. A total of 63 553 basin geosystems were identified on the map, averaging 68 km2 in area. Accuracy verification of identifying the basin boundaries showed a good agreement of areal and geometric characteristics of the method used with expert approach. In test areas, the men difference of the indicators of the area of the basins identified automatically and by use of the expert approach made up 3.6%. For areas with weakly dissected lowland topography this error does not exceed 5% while it is about 2% in areas with relatively dissected elevated topography. The basin geosystems thus identified are operational-territorial units with respect to which the geospatial data base is generated to characterize the natural-resource potential of the European territory of Russia. An example is provided for the generation of the geospatial database containing hydrological information covering 1763 hydrological stations collecting streamflow data. 相似文献
11.
Using high resolution satellite imagery to estimate cropped area in Guatemala and Haiti 总被引：1，自引：0，他引：1
K. Grace G.J. Husak L. Harrison D. Pedreros J. Michaelsen 《Applied geography (Sevenoaks, England)》2012,32(2):433-440
Guatemala and Haiti are two of the most food insecure nations in the Western Hemisphere. Measurements of food availability and access are instrumental in developing targeted hunger reduction strategies yet no estimates of cropped area (a critical input in the calculation of food production) at either a national or sub-national-level exist. The purpose of this research is to produce estimates of cropped area for Guatemala and Haiti using an area frame sampling approach and very high resolution (∼1 m) satellite imagery. Related research has combined livelihood data with topographic information to construct cropped area estimates in other settings using generalized additive models. We expand this approach with the inclusion of specific population variables in place of the livelihood data. We produce estimates of cropped area for the two countries and sub-national units and our results highlight the significance and complexity of incorporating explicit population characteristics into models of cropped area. 相似文献
12.
河南信阳茶叶资源环境优势及发展 总被引：4，自引：0，他引：4
信阳茶叶是河南省南部大别-桐柏山区的重要经济作物资源之一。该区域地处北亚热带，气候温暖湿润，生态环境复杂多样，植物资源丰富，是河南的鱼米之乡。气候条件独特，利于优质茶叶生长。因此，虽然以信阳毛尖为代表的信阳茶区茶叶面积小，茶叶总产量少，但产品质量上乘，深受茶叶消费者的喜爱，是全国名优绿茶重要产区。依据信阳茶区茶叶资源环境优势，提出进行名优绿色无公害茶产品的开发；组织茶叶产业化发展；加强信阳茶叶生产的标准化研究推广工作和加强对外经济技术联系协作，为河南省信阳茶叶可持续发展提供科学依据。 相似文献
13.
Jingwei Hou Xingang Fan Rentao Liu 《International journal of geographical information science》2016,30(12):2462-2485
The optimal spatial allocation of irrigation water under uncertainty has become a serious concern because of irrigation water shortage and uncertain factors that affect irrigation water allocation. In this study, an optimal multi-objective model for irrigation water allocation under uncertainty is developed to maximise the economic benefit of crops and minimise the operation cost and water deficit of crop irrigation. The original and optimal plantation structure, irrigation mode and soil water content are acquired through geospatial technology. A bilayer nested optimisation (BLNO) algorithm is designed to produce multiple individuals of design vectors using an ant colony neural network algorithm for an outer optimisation. Meanwhile, a continuous adaptive ant colony (CAAC) algorithm is used for inner optimisation to calculate the interval values of the uncertain model. The crop distribution and irrigation mode are obtained to parameterise the planting area and the water demand of each crop and each block in the multi-objective model. This model is then solved and analysed. Compared to the optimal schemes obtained from an inexact two-stage fuzzy-stochastic programming and the CAAC, respectively, BLNO can effectively and efficiently solve the optimal spatial allocation of irrigation water under uncertainty. This method can spatially maximise the economic benefit of crops and minimise the operation cost and water deficit of crop irrigation using lower and upper bound maps whilst visually obtaining the exact crop type, reasonable irrigation method and precise water demand for each block and for the entire irrigated area. 相似文献
14.
Karyn Morrissey Graham Clarke Dimitris Ballas Stephen Hynes Cathal O'Donoghue 《Area》2008,40(3):354-364
This paper analyses the effect accessibility has on General Practitioner (GP) utilisation rates at the sub-national level for Ireland. Specifically, the aim of this paper is to estimate whether there is an urban–rural differential in GP utilisation rates. We do this by simulating micro-level healthcare data. Using this synthetic data, simple logit models are employed to estimate the likelihood that individuals in different jurisdictions will attend a GP surgery. These individual logit estimates are then inputted into a spatial interaction model to highlight areas with low GP accessibility given their health status. The policy implications of these results are discussed in relation to both the healthcare literature and current Irish healthcare policy. 相似文献
15.
航空情报资料是空中交通地理活动所必需或所产生的航空地理数据,在信息化管理过程中面临着多源异构数据的集中管理、统一维护和分布使用等需求。GML作为开放的空间数据模型标准,为航空地理数据的交换和共享提供了要素编码方法和数据交换规范。针对航空信息化系统建设中对规范的航空地理数据的应用需求,在研究航空地理数据特点的基础上,通过分析航空地理数据与GML模型之间的映射关系,以航线管理系统中基础航空情报数据库的建设为例,基于GML规范设计了航空地理数据模型,阐明了数据处理流程,为建立标准化的航空信息数据仓库进行了有益的尝试。 相似文献
16.
Spatial accessibility measures are an important policy tool for managing healthcare provision and reducing health inequality. The two‐step floating catchment area technique, in common with many alternative methodologies, requires that demand‐side population be estimated using spatial interpolation techniques. This article studies the implications of adopting differing spatial representations of population on healthcare accessibility modeling outcomes. Results indicate that a dasymetric model yields lower accessibility scores than a standard pro rata model. More important, the difference is spatially disproportionate, suggesting that the degree of disadvantage experienced in rural areas may be greater than has previously been recognized. 相似文献
17.
This paper demonstrates the importance of disaggregating population data aggregated by census tracts or other units, for more realistic population distribution/location. A newly developed mapping method, the Cadastral-based Expert Dasymetric System (CEDS), calculates population in hyper-heterogeneous urban areas better than traditional mapping techniques. A case study estimating population potentially impacted by flood hazard in New York City compares the impacted population determined by CEDS with that derived by centroid-containment method and filtered areal-weighting interpolation. Compared to CEDS, 37% and 72% fewer people are estimated to be at risk from floods city-wide, using conventional areal weighting of census data, and centroid-containment selection, respectively. Undercounting of impacted population could have serious implications for emergency management and disaster planning. Ethnic/racial populations are also spatially disaggregated to determine any environmental justice impacts with flood risk. Minorities are disproportionately undercounted using traditional methods. Underestimating more vulnerable sub-populations impairs preparedness and relief efforts. 相似文献
18.
Multiple Regressive Pattern Recognition Technique (MRPRT) is an adapted approach for improved geologic resource estimation.
We developed and tested this approach for the Platinum (Pt) bearing region near Goodnews Bay, Alaska, which presents an example
of a complex depositional environment. We applied geospatial and pattern recognition methods to assess the spatial distribution
of offshore Pt in the Goodnews Bay area from point data collected by various agencies. We used the coefficient of correlation
(r) and the Nash–Sutcliffe efficiency (E) to quantitatively assess the degree of accuracy of the estimated Pt distribution. We split the study area, based on trend
analysis, into two regions: inside the Bay and outside the Bay. We could not obtain appreciable estimates from the geospatial
and pattern recognition methods. Using MRPRT, we were able to improve r from 0.57 to 0.93 and the E from 28.31 to 92.91 inside the Bay. We achieved improvement in r from 0.55 to 0.61 and E from 28.46 to 34.52 outside the Bay. The reasons for a non-significant improvement outside the Bay have been discussed. The
results indicate that the proposed MRPRT has wide application potential in georesource estimation where input data is often
scarce. 相似文献
19.
疏勒河流域双塔灌区种植结构变化及其原因 总被引：3，自引：0，他引：3
基于1996-2010年双塔灌区各乡（镇）农作物类型、种植面积、供水定额、用水定额、作物单产及价格等资料,探讨了气候变化背景下农业种植结构调整原因及其影响。结果表明：研究区2010年作物种植面积较1996年增长2.3倍,其中粮食作物种植面积减少,经济作物和其他作物种植面积增加,农作物总产值和单位产值均明显提高,说明当地种植结构调整优化在产生经济效益方面效果明显。当地种植结构调整主要受自然条件、政策指导、历史根源、农民意愿、市场调节、灌溉供水条件等多方面因素的影响,其中自然条件中的水资源供应状况主要影响作物种植面积,其他因素影响作物种植类型。通过种植结构调整,当地农业产值在增长同时,用水紧张现象较以前有所缓解,地表水基本可以满足农田灌溉需求,减少了对地下水的使用,从而对保护当地生态具有重要意义。 相似文献
20.
Extensive parts of Arctic permafrost-dominated lowlands were affected by large-scale permafrost degradation, mainly through Holocene thermokarst activity. The effect of thermokarst is nowadays observed in most periglacial lowlands of the Arctic. Since permafrost degradation is a consequence as well as a significant factor of global climate change, it is necessary to develop efficient methods for the quantification of its past and current magnitude. We developed a procedure for the quantification of periglacial lowland terrain types with a focus on degradation features and applied it to the Cape Mamontov Klyk area in the western Laptev Sea region. Our terrain classification approach was based on a combination of geospatial datasets, including a supervised maximum likelihood classification applied to Landsat-7 ETM+ data and digital elevation data. Thirteen final terrain surface classes were extracted and subsequently characterized in terms of relevance to thermokarst and degradation of ice-rich deposits. 78% of the investigated area was estimated to be affected by permafrost degradation. The overall classification accuracy was 79%. Thermokarst did not develop evenly on the coastal plain, as indicated by the increasingly dense coverage of thermokarst-related areas from south to north. This regionally focused procedure can be extended to other areas to provide the highly detailed periglacial terrain mapping capabilities currently lacking in global-scale permafrost datasets. 相似文献