Implications of sensor design for coral reef detection: Upscaling ground hyperspectral imagery in spatial and spectral scales

Remote sensing offers a potential tool for large scale environmental surveying and monitoring. However, remote observations of coral reefs are difficult especially due to the spatial and spectral complexity of the target compared to sensor specifications as well as the environmental implications of the water medium above. The development of sensors is driven by technological advances and the desired products. Currently, spaceborne systems are technologically limited to a choice between high spectral resolution and high spatial resolution, but not both. The current study explores the dilemma of whether future sensor design for marine monitoring should prioritise on improving their spatial or spectral resolution. To address this question, a spatially and spectrally resampled ground-level hyperspectral image was used to test two classification elements: (1) how the tradeoff between spatial and spectral resolutions affects classification; and (2) how a noise reduction by majority filter might improve classification accuracy. The studied reef, in the Gulf of Aqaba (Eilat), Israel, is heterogeneous and complex so the local substrate patches are generally finer than currently available imagery. Therefore, the tested spatial resolution was broadly divided into four scale categories from five millimeters to one meter. Spectral resolution resampling aimed to mimic currently available and forthcoming spaceborne sensors such as (1) Environmental Mapping and Analysis Program (EnMAP) that is characterized by 25 bands of 6.5 nm width; (2) VENμS with 12 narrow bands; and (3) the WorldView series with broadband multispectral resolution. Results suggest that spatial resolution should generally be prioritized for coral reef classification because the finer spatial scale tested (pixel size < 0.1 m) may compensate for some low spectral resolution drawbacks. In this regard, it is shown that the post-classification majority filtering substantially improves the accuracy of all pixel sizes up to the point where the kernel size reaches the average unit size (pixel < 0.25 m). However, careful investigation as to the effect of band distribution and choice could improve the sensor suitability for the marine environment task. This in mind, while the focus in this study was on the technologically limited spaceborne design, aerial sensors may presently provide an opportunity to implement the suggested setup.     

Quantitative Analysis of Scale of Aeromagnetic Data Raises Questions About Geologic-Map Scale

A recently published study has shown that small-scale geologic map data can reproduce mineral assessments made with considerably larger scale data. This result contradicts conventional wisdom about the importance of scale in mineral exploration, at least for regional studies. In order to formally investigate aspects of scale, a weights-of-evidence analysis using known gold occurrences and deposits in the Central Lapland Greenstone Belt of Finland as training sites provided a test of the predictive power of the aeromagnetic data. These orogenic-mesothermal-type gold occurrences and deposits have strong lithologic and structural controls associated with long (up to several kilometers), narrow (up to hundreds of meters) hydrothermal alteration zones with associated magnetic lows. The aeromagnetic data were processed using conventional geophysical methods of successive upward continuation simulating terrane clearance or ‘flight height’ from the original 30 m to an artificial 2000 m. The analyses show, as expected, that the predictive power of aeromagnetic data, as measured by the weights-of-evidence contrast, decreases with increasing flight height. Interestingly, the Moran autocorrelation of aeromagnetic data representing differing flight height, that is spatial scales, decreases with decreasing resolution of source data. The Moran autocorrelation coefficient scems to be another measure of the quality of the aeromagnetic data for predicting exploration targets.     

阔克沙勒—吉萨尔地震活动时间的多重分形研究

应用多重分形的标度指数谱f(α)～α方法分析阔克沙勒——吉萨尔地区地震活动时间序列,发现一定范围内地震多重分形f(α)～α在大震前有明显的异常显示。说明f(α)谱研究地震的多重分形,简单、有效、能全面地描述地震时间分布这类不均匀分形集。     

天文地质年代表与旋回地层学研究进展

Rio等（2003）依据旋回地层学研究成果提出了“天文地质年代表”，旋回地层学研究是依据地层记录中的旋回与有关米氏旋回来确定地质时间。轨道（或天文）方法已被确定为建立2004年“国际地质年表”（由国际地层委员会确认）的重要方法之一（Gradstein等，2004）。我国在新近系、古近系、下侏罗统、二叠系等陆相沉积的旋回地层研究方面已取得一批成果。     

Explicit Adaptive Symplectic (Easy) Integrators: A Scaling Invariant Generalisation of the Levi-Civitaand KS Regularisations

We present a generalisation of the Levi-Civita and Kustaanheimo-Stiefel regularisation. This allows the use of more general time rescalings. In particular, it is possible to find a regularisation which removes the singularity of the equations and preserves scaling invariance. In addition, these equations can, in certain cases, be integrated with explicit symplectic Runge-Kutta-Nyström methods. The combination of both techniques gives an explicit adaptive symplectic (EASY) integrator. We apply those methods to some perturbations of the Kepler problem and illustrate, by means of some numerical examples, when scaling invariant regularisations are more efficient that the LC/KS regularisation.     

楚雄盆地上三叠统储集体成因类型及几何模式

楚雄盆地经历多期构造变形.晚三叠世,盆地北部由盆底扇深水环境过渡到沿岸砂坝和三角洲环境.该时期形成辫状河道砂、砾岩体、滨滩砂岩体,河口坝砂岩体和分流河道充填砂岩体四类储集体,构成三种相结合,即扇储集体、三角洲前缘储集体和三角洲平原储集体,几何形态对应为透镜状、带状和不规则状.     

尺度推绎研究中的几点基本问题

尺度推绎作为将一个尺度上的信息推绎到另一个尺度上的过程,具有尺度依赖性、模型非线性和研究的复杂性等特征,其理论基础主要有等级理论、分形理论等,其研究的关键问题表现为尺度选择与信息提取问题、尺度域与特征尺度问题、模型问题等方面。针对相邻尺度推绎和跨尺度推绎两种情况,还介绍了不同情况下尺度推绎研究的基本思路。尺度推绎作为现代地学、生态学等学科研究的重要问题之一,其发展需要多学科的交流和理论与技术的创新。     

Using pan-sharpened high resolution satellite data to improve impervious surfaces estimation

Impervious surface is an important environmental and socio-economic indicator for numerous urban studies. While a large number of researches have been conducted to estimate the area and distribution of impervious surface from satellite data, the accuracy for impervious surface estimation (ISE) is insufficient due to high diversity of urban land cover types. This study evaluated the use of panchromatic (PAN) data in very high resolution satellite image for improving the accuracy of ISE by various pan-sharpening approaches, with a further comprehensive analysis of its scale effects. Three benchmark pan-sharpening approaches, Gram-Schmidt (GS), PANSHARP and principal component analysis (PCA) were applied to WorldView-2 in three spots of Hong Kong. The on-screen digitization were carried out based on Google Map and the results were viewed as referenced impervious surfaces. The referenced impervious surfaces and the ISE results were then re-scaled to various spatial resolutions to obtain the percentage of impervious surfaces. The correlation coefficient (CC) and root mean square error (RMSE) were adopted as the quantitative indicator to assess the accuracy. The accuracy differences between three research areas were further illustrated by the average local variance (ALV) which was used for landscape pattern analysis. The experimental results suggested that 1) three research regions have various landscape patterns; 2) ISE accuracy extracted from pan-sharpened data was better than ISE from original multispectral (MS) data; and 3) this improvement has a noticeable scale effects with various resolutions. The improvement was reduced slightly as the resolution became coarser.     

There’s nothing inherent about scale: political ecology, the local trap, and the politics of development in the Brazilian Amazon

This paper argues that research in political ecology would benefit from more explicit and careful attention to the question of scale and scalar politics. Although political ecologists have extensively considered scale as a methodological question, they have yet to develop an explicit theoretical approach to scale as an object of inquiry. We highlight one principal drawback to this underdeveloped approach to scale: what we call “the local trap” in which political ecologists assume that organization, policies, and action at the local scale are inherently more likely to have desired social and ecological effects than activities organized at other scales. Over the past 10 years or so, an increasingly sophisticated literature on scale has been developing among scholars in geography working in the political economy tradition. This literature has argued that scale is socially produced rather than ontologically given. Therefore, there is nothing inherent about any scale, and so the local scale cannot be intrinsically more desirable than other scales. We suggest that a greater engagement with this scale literature offers political ecology a theoretical way out of the local trap. As a first approximation of the kind of scalar analysis we advocate, we present a case study that examines the scalar politics that have shaped environmental change in the Brazilian Amazon.     

ON THE USE OF MOVABLE-BED MODELS FOR RIVER PROBLEMS:A STATE-OF-THE-ART

I. INTRODUCTIONMore than a decade ago, under tile auspices of DELFT HYDRAULICS an overview on the use ofmodels for river problems was given (de Vries & van der Zwaard. 1975). Since then a better understanding of morphological processes in rivers has been obtained, their mathematical formulation hasbeen improved and computer facilities have been expended. Scale models and mathematical models arein use. but their field of application is gradually changing. It seems that the better ma…