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11.
Peter A. Johnson Renee Sieber Teresa Scassa Monica Stephens Pamela Robinson 《Transactions in GIS》2017,21(3):434-445
The provision of open data by governments at all levels has rapidly increased over recent years. Given that one of the dominant motivations for the provision of open data is to generate ‘value’, both economic and civic, there are valid concerns over the costs incurred in this pursuit. Typically, costs of open data are framed as internal to the data providing government. Building on the strong history of GIScience research on data provision via spatial data infrastructures, this article considers both the direct and indirect costs of open data provision, framing four main areas of indirect costs: citizen participation challenges, uneven provision across geography and user types, subsidy of private sector activities, and the creation of inroads for corporate influence on government. These areas of indirect cost lead to the development of critical questions, including constituency, purpose, enablement, protection, and priorities. These questions are posed as a guide to governments that provide open data in addressing the indirect costs of open data. 相似文献
12.
Jin Xing Renee E. Sieber 《International journal of geographical information science》2016,30(3):573-593
ABSTRACTBig data have shifted spatial optimization from a purely computational-intensive problem to a data-intensive challenge. This is especially the case for spatiotemporal (ST) land use/land cover change (LUCC) research. In addition to greater variety, for example, from sensing platforms, big data offer datasets at higher spatial and temporal resolutions; these new offerings require new methods to optimize data handling and analysis. We propose a LUCC-based geospatial cyberinfrastructure (GCI) that optimizes big data handling and analysis, in this case with raster data. The GCI provides three levels of optimization. First, we employ spatial optimization with graph-based image segmentation. Second, we propose ST Atom Model to temporally optimize the image segments for LUCC. At last, the first two domain ST optimizations are supported by the computational optimization for big data analysis. The evaluation is conducted using DMTI (DMTI Spatial Inc.) Satellite StreetView imagery datasets acquired for the Greater Montreal area, Canada in 2006, 2009, and 2012 (534 GB, 60 cm spatial resolution, RGB image). Our LUCC-based GCI builds an optimization bridge among LUCC, ST modelling, and big data. 相似文献
13.
Alpine Ecosystems of Northwest Yunnan, China： an Initial Assessment for Conservation 总被引：1，自引：1，他引：0
Ruth Sherman Renee Mullen LI Haomin FANG Zhendong WANG Yi 《山地科学学报》2007,4(3):181-192
Implementing conservation actions on-the-ground is not a straightforward process,especially when faced with high scientific uncertainty due to limited available information. This is especially acute in regions of the world that harbor many unique species that have not been well studied,such as the alpine zone of the Hengduan Mountains of Northwest Yunnan (NWY),a global biodiversity hotspot and site of The Nature Conservancy’s Yunnan Great Rivers Project. We conducted a quantitative,but rapid regional-level assessment of the alpine flora across NWY to provide a broad-based understanding of local and regional patterns of the alpine flora,the first large-scale analysis of alpine biodiversity patterns in this region. Multivariate analyses were used to classify the major plant community types and link community patterns to habitat variables. Our analysis indicated that most species had small distributions and/or small population sizes. Strong patterns emerged with higher diversity in the more northern mountains,but beta diversity was high,averaging only 10% among sites. The ordinations indicated that elevation and geographic location were the dominant environ-mental gradients underlying the differences in the species composition among communities. The high beta diversity across the alpine of these mountains implies that conservation strategies ultimately will require the protection of large numbers of species over a large geographical area. However,prioritiza-tion should be given to areas where potential payoffs are greatest. Sites with high species richness also have a greater number of endemic species,and,by focusing efforts on these sites,conservation investments would be maximized by protecting the greatest number of unique species. 相似文献
14.
Two distinct crustal provinces have been identified in the southern mid-continent based on U–Pb crystallization ages. Both
contain large volumes of undeformed granite and rhyolite, with minor amounts of metamorphic rock and mafic intrusions. The
Eastern Granite-Rhyolite province is characterized by felsic rocks with crystallization ages of 1,470 ± 30 Ma and exposures
are restricted to the St. Francois Mountains in southeastern Missouri. Similarly, the Southern Granite-Rhyolite (SGR) province
is characterized by felsic units with ages of 1,370 ± 30 Ma with primary exposures in the eastern Arbuckle Mountains of southern
Oklahoma. Within the SGR province three magmatic pulses can be identified starting at 1,400, 1,370, and 1,340 Ma. Although
the crystallization ages are different, the Sm–Nd isotopic signatures are similar for the units exposed in these areas as
well as the buried basement in between. Depleted mantle model ages for rocks within the Arbuckle Mountains range from 1,530
to 1,430 Ma with ɛNd(t) values of +3.2 to +4.1 while units of the St. Francois Mountains range from 1,550 to 1,430 Ma and +4.5 to +4.7. Comparison
of Sm–Nd isotopic data also indicate similarities between the 147Sm/144Nd and 143Nd/144Nd ratios for the rock units in these areas suggesting a common source. 相似文献
15.
David A. Clague Alice S. Davis James L. Bischoff Jacqueline E. Dixon Renee Geyer 《Bulletin of Volcanology》2000,61(7):437-449
Glassy bubble-wall fragments, morphologically similar to littoral limu o Pele, have been found in volcanic sands erupted
on Lō'ihi Seamount and along the submarine east rift zone of Kīlauea Volcano. The limu o Pele fragments are undegassed with
respect to H2O and S and formed by mild steam explosions. Angular glass sand fragments apparently form at similar, and greater, depths
by cooling-contraction granulation. The limu o Pele fragments from Lō'ihi Seamount are dominantly tholeiitic basalt containing
6.25–7.25% MgO. None of the limu o Pele samples from Lō'ihi Seamount contains less than 5.57% MgO, suggesting that higher
viscosity magmas do not form lava bubbles. The dissolved CO2 and H2O contents of 7 of the limu o Pele fragments indicate eruption at 1200±300 m depth (120±30 bar). These pressures exceed that
generally thought to limit steam explosions. We conclude that hydrovolcanic eruptions are possible, with appropriate pre-mixing
conditions, at pressures as great as 120 bar.
Received: 22 December 1998 / Accepted: 16 July 1999 相似文献
16.
We evaluate the greenhouse gas footprint of natural gas obtained by high-volume hydraulic fracturing from shale formations,
focusing on methane emissions. Natural gas is composed largely of methane, and 3.6% to 7.9% of the methane from shale-gas
production escapes to the atmosphere in venting and leaks over the life-time of a well. These methane emissions are at least
30% more than and perhaps more than twice as great as those from conventional gas. The higher emissions from shale gas occur
at the time wells are hydraulically fractured—as methane escapes from flow-back return fluids—and during drill out following
the fracturing. Methane is a powerful greenhouse gas, with a global warming potential that is far greater than that of carbon
dioxide, particularly over the time horizon of the first few decades following emission. Methane contributes substantially
to the greenhouse gas footprint of shale gas on shorter time scales, dominating it on a 20-year time horizon. The footprint
for shale gas is greater than that for conventional gas or oil when viewed on any time horizon, but particularly so over 20 years.
Compared to coal, the footprint of shale gas is at least 20% greater and perhaps more than twice as great on the 20-year horizon
and is comparable when compared over 100 years. 相似文献
17.
Adam T. Cross Renee Young Paul Nevill Tein McDonald Karel Prach James Aronson Grant W. Wardell-Johnson Kingsley W. Dixon 《Environmental Earth Sciences》2018,77(6):256
Confusion surrounding the definition and application of terminology in post-mining ecological repair has resulted in uncertainty for industry, the scientific community and regulators. This lack of clarity may underrepresent high aspirations or could be misused to disguise low aspirations and so is problematic for setting objectives, establishing goals and assessing recovery trajectories. We respond to a recently published analysis of the ecosystem repair literature, where we highlight inconsistencies stemming from inadequate reference to a large proportion of the restoration and rehabilitation literature. We outline increasingly well-accepted and internationally applied definitions concerning the restoration and recovery process and invite both the mining industry and policy-makers to re-examine their terminology in the interests of attaining an internationally agreed nomenclature. Clarity in the use and understanding of terminology will align post-mining targets with community expectation, enhance the capacity of the mining industry to understand and meet these targets, and foster better analysis and more industry-relevant discussion of recovery methodologies by the scientific community and practitioners. 相似文献
18.
Since the 1970s, activity diaries have been the principal source of data used by geographers and urban planners to capture human mobility patterns; however, memory recall requirements and participant burden are limiting features of this approach. While handheld GPS devices were initially used to simply validate activity diaries, the ubiquity of smartphones makes GPS-based technology a viable alternative for collecting human mobility data. This research visualises human mobility patterns using spatiotemporally GPS-rich traces collected from 24 participants during a pilot study of a new smartphone application—Wander. The results illustrate the utility of such data for capturing individuals’ multi-nodal activity spaces to better understand people–place interactions in the context of increasingly fluid and mobile lifestyles. Finally, we draw on our experiences of implementing this pilot study to discuss the benefits and limitations of this technology for its broader application in domains such as transportation planning, tourism management, and in the management of crime and disorder. 相似文献
19.
Recent increases in the use of Web 2.0 and Geoweb technologies by citizens have led many governments to investigate the adoption of these technologies. This research examines the motivations driving multiple levels of government in Quebec, Canada to consider the adoption of the Geoweb within a context of rural development. We present results from a series of interviews with key government representatives that identifies the SWOT (strengths, weaknesses, opportunities, and threats) of the Geoweb within provincial and municipal government. Respondents define two implementations of the Geoweb, informational and participatory, indicating that SWOT differs for each. This research concludes that for government to implement an informational Geoweb, there are few barriers, but that a participatory Geoweb will require a more substantial, and potentially long-term renegotiation of the relationship between citizen and government. 相似文献
20.
Renée Heilbronner 《Journal of the Geological Society of India》2010,75(1):160-170
The paper is concerned with the combined application of two methods for microstructure and texture analysis: (1) optical orientation
and misorientation imaging and (2) autocorrelation function (ACF). Using two different samples, the usefulness of the methods
and the quality of the results are discussed. One sample is a quartzite layer from the limb of a small scale fold in the Suretta
Nappe (ValAvers, Switzerland) which was deformed under upper greenschist conditions, the other is a sample of Black Hills
quartzite, experimentally sheared in dislocation creep. Using the method of computer-integrated polarization microscopy (CIP),
c-axis orientation and misorientation images were prepared and pole figures were calculated from the azimuth and inclination
images. Misorientation images were prepared and analyzed in a number of ways: (1) In as much as misorientation images constitute
texture maps, they visualize the geometry and spatial distribution of texture domains; they show if the texture domains are
spatially coherent, i.e., if the rock is domainal or not. (2) Thresholded misorientation images allow the calculation of the
volume fraction of texture domains, which is a means of estimating the texture intensification independent of the shape of
the pole figure skeleton. (3) From the ACF of thresholded misorientation images the average grain size and shape in those
domains can be derived. (4) From the shape of the domains (if they exist as spatial entities), the strain or strain partitioning
as well as the rheological contrast can be estimated. The paper seeks to demonstrate the importance of localized texture analysis.
The aim is to discuss the quality of the results that can be obtained. The samples were chosen because one is domainal the
other one is not. A full discussion of the geological implications of the results of the analysis is outside the scope of
this contribution. 相似文献