bluuebunny/crossref_metadata_2025 huggingface dataset:
EXPLORING THE IMPACT OF VISUAL COMPLEXITY LEVELS IN 3D CITY MODELS ON THE ACCURACY OF INDIVIDUALS’ ORIENTATION AND COGNITIVE MAPS
Authors: Rautenbach V. , Çöltekin A. , Coetzee S.
Published: August 2015

Abstract. In this paper we report results from a qualitative user experiment (n=107) designed to contribute to understanding the impact of various levels of complexity (mainly based on levels of detail, i.e., LoD) in 3D city models, specifically on the participants’ orientation and cognitive (mental) maps. The experiment consisted of a number of tasks motivated by spatial cognition theory where participants (among other things) were given orientation tasks, and in one case also produced sketches of a path they ‘travelled’ in a virtual environment. The experiments were conducted in groups, where individuals provided responses on an answer sheet. The preliminary results based on descriptive statistics and qualitative sketch analyses suggest that very little information (i.e., a low LoD model of a smaller area) might have a negative impact on the accuracy of cognitive maps constructed based on a virtual experience. Building an accurate cognitive map is an inherently desired effect of the visualizations in planning tasks, thus the findings are important for understanding how to develop better-suited 3D visualizations such as 3D city models. In this study, we specifically discuss the suitability of different levels of visual complexity for development planning (urban planning), one of the domains where 3D city models are most relevant.
A COMPARISON OF METHODS FOR THE APPROXIMATION AND ANALYSIS OF RAINFALL FIELDS IN ENVIRONMENTAL APPLICATIONS
Authors: Patané G. , Cerri A. , Skytt V. , Pittaluga S. , Biasotti S. , Sobrero D. , Dokken T. , Spagnuolo M.
Published: August 2015

Abstract. Digital environmental data are becoming commonplace and the amount of information they provide is huge, yet complex to process, due to the size, variety, and dynamic nature of the data captured by the available sensing devices. Making use of the data largely relies on the availability of efficient methods to extract meaningful information, and requires to process the environmental events at the speed data are acquired. This paper focuses on the evaluation of methods to approximate observed rain data, in real conditions of sparsity of the observations. The novelty stands in the selection of a particularly complex area, Liguria region, located in the north-west of Italy, where the orography and the closeness to the sea causes complex hydro-meteorological events. Approximation results are compared on a fine granularity in terms of cumulated rain interval used, gathered from two different rain gauge networks, with different characteristics and spatial distribution. Moreover, beside traditional cross-validation comparison, we provide a qualitative comparison based on the analysis of the number and location of maxima of the approximation. Rain maxima are indeed crucial features of rain fields needed for storm tracking, to support effective monitoring of meteorological events.
POINT CLOUD SERVER (PCS) : POINT CLOUDS IN-BASE MANAGEMENT AND PROCESSING
Authors: Cura R. , Perret J. , Paparoditis N.
Published: August 2015

Abstract. In addition to the traditional Geographic Information System (GIS) data such as images and vectors, point cloud data has become more available. It is appreciated for its precision and true three-Dimensional (3D) nature. However, managing the point cloud can be difficult due to scaling problems and specificities of this data type. Several methods exist but are usually fairly specialised and solve only one aspect of the management problem. In this work, we propose a complete and efficient point cloud management system based on a database server that works on groups of points rather than individual points. This system is specifically designed to solve all the needs of point cloud users: fast loading, compressed storage, powerful filtering, easy data access and exporting, and integrated processing. Moreover, the system fully integrates metadata (like sensor position) and can conjointly use point clouds with images, vectors, and other point clouds. The system also offers in-base processing for easy prototyping and parallel processing and can scale well. Lastly, the system is built on open source technologies; therefore it can be easily extended and customised. We test the system will several billion points of point clouds from Lidar (aerial and terrestrial ) and stereo-vision. We demonstrate ~ 400 million pts/h loading speed, user-transparent greater than 2 to 4:1 compression ratio, filtering in the approximately 50 ms range, and output of about a million pts/s, along with classical processing, such as object detection.
DETECTION AND CLASSIFICATION OF POLE-LIKE OBJECTS FROM MOBILE MAPPING DATA
Authors: Fukano K. , Masuda H.
Published: August 2015

Abstract. Laser scanners on a vehicle-based mobile mapping system can capture 3D point-clouds of roads and roadside objects. Since roadside objects have to be maintained periodically, their 3D models are useful for planning maintenance tasks. In our previous work, we proposed a method for detecting cylindrical poles and planar plates in a point-cloud. However, it is often required to further classify pole-like objects into utility poles, streetlights, traffic signals and signs, which are managed by different organizations. In addition, our previous method may fail to extract low pole-like objects, which are often observed in urban residential areas. In this paper, we propose new methods for extracting and classifying pole-like objects. In our method, we robustly extract a wide variety of poles by converting point-clouds into wireframe models and calculating cross-sections between wireframe models and horizontal cutting planes. For classifying pole-like objects, we subdivide a pole-like object into five subsets by extracting poles and planes, and calculate feature values of each subset. Then we apply a supervised machine learning method using feature variables of subsets. In our experiments, our method could achieve excellent results for detection and classification of pole-like objects.
REFERENCE VALUE PROVISION SCHEMES FOR ATTENUATION CORRECTION OF FULL-WAVEFORM AIRBORNE LASER SCANNER DATA
Authors: Richter K. , Blaskow R. , Stelling N. , Maas H.-G.
Published: August 2015

Abstract. The characterization of the vertical forest structure is highly relevant for ecological research and for better understanding forest ecosystems. Full-waveform airborne laser scanner systems providing a complete time-resolved digitization of every laser pulse echo may deliver very valuable information on the biophysical structure in forest stands. To exploit the great potential offered by full-waveform airborne laser scanning data, the development of suitable voxel based data analysis methods is straightforward. Beyond extracting additional 3D points, it is very promising to derive voxel attributes from the digitized waveform directly. However, the ’history’ of each laser pulse echo is characterized by attenuation effects caused by reflections in higher regions of the crown. As a result, the received waveform signals within the canopy have a lower amplitude than it would be observed for an identical structure without the previous canopy structure interactions (Romanczyk et al., 2012). To achieve a radiometrically correct voxel space representation, the loss of signal strength caused by partial reflections on the path of a laser pulse through the canopy has to be compensated by applying suitable attenuation correction models. The basic idea of the correction procedure is to enhance the waveform intensity values in lower parts of the canopy for portions of the pulse intensity, which have been reflected in higher parts of the canopy. To estimate the enhancement factor an appropriate reference value has to be derived from the data itself. Based on pulse history correction schemes presented in previous publications, the paper will discuss several approaches for reference value estimation. Furthermore, the results of experiments with two different data sets (leaf-on/leaf-off) are presented.
RIGOROUS STRIP ADJUSTMENT OF AIRBORNE LASERSCANNING DATA BASED ON THE ICP ALGORITHM
Authors: Glira P. , Pfeifer N. , Briese C. , Ressl C.
Published: August 2015

Abstract. Airborne Laser Scanning (ALS) is an efficient method for the acquisition of dense and accurate point clouds over extended areas. To ensure a gapless coverage of the area, point clouds are collected strip wise with a considerable overlap. The redundant information contained in these overlap areas can be used, together with ground-truth data, to re-calibrate the ALS system and to compensate for systematic measurement errors. This process, usually denoted as strip adjustment, leads to an improved georeferencing of the ALS strips, or in other words, to a higher data quality of the acquired point clouds. We present a fully automatic strip adjustment method that (a) uses the original scanner and trajectory measurements, (b) performs an on-the-job calibration of the entire ALS multisensor system, and (c) corrects the trajectory errors individually for each strip. Like in the Iterative Closest Point (ICP) algorithm, correspondences are established iteratively and directly between points of overlapping ALS strips (avoiding a time-consuming segmentation and/or interpolation of the point clouds). The suitability of the method for large amounts of data is demonstrated on the basis of an ALS block consisting of 103 strips.
EVALUATION OF WAVELET DENOISING METHODS FOR SMALL-SCALE JOINT ROUGHNESS ESTIMATION USING TERRESTRIAL LASER SCANNING
Authors: Bitenc M. , Kieffer D. S. , Khoshelham K.
Published: August 2015

Abstract. The precision of Terrestrial Laser Scanning (TLS) data depends mainly on the inherent random range error, which hinders extraction of small details from TLS measurements. New post processing algorithms have been developed that reduce or eliminate the noise and therefore enable modelling details at a smaller scale than one would traditionally expect. The aim of this research is to find the optimum denoising method such that the corrected TLS data provides a reliable estimation of small-scale rock joint roughness. Two wavelet-based denoising methods are considered, namely Discrete Wavelet Transform (DWT) and Stationary Wavelet Transform (SWT), in combination with different thresholding procedures. The question is, which technique provides a more accurate roughness estimates considering (i) wavelet transform (SWT or DWT), (ii) thresholding method (fixed-form or penalised low) and (iii) thresholding mode (soft or hard). The performance of denoising methods is tested by two analyses, namely method noise and method sensitivity to noise. The reference data are precise Advanced TOpometric Sensor (ATOS) measurements obtained on 20 × 30 cm rock joint sample, which are for the second analysis corrupted by different levels of noise. With such a controlled noise level experiments it is possible to evaluate the methods’ performance for different amounts of noise, which might be present in TLS data. Qualitative visual checks of denoised surfaces and quantitative parameters such as grid height and roughness are considered in a comparative analysis of denoising methods. Results indicate that the preferred method for realistic roughness estimation is DWT with penalised low hard thresholding.
SIMPLE APPROACHES TO IMPROVE THE AUTOMATIC INVENTORY OF ZEBRA CROSSING FROM MLS DATA
Authors: Arias P. , Riveiro B. , Soilán M. , Díaz-Vilariño L. , Martínez-Sánchez J.
Published: August 2015

Abstract. The city management is increasingly supported by information technologies, leading to paradigms such as smart cities, where decision-makers, companies and citizens are continuously interconnected. 3D modelling turns of great relevance when the city has to be managed making use of geospatial databases or Geographic Information Systems. On the other hand, laser scanning technology has experienced a significant growth in the last years, and particularly, terrestrial mobile laser scanning platforms are being more and more used with inventory purposes in both cities and road environments. Consequently, large datasets are available to produce the geometric basis for the city model; however, this data is not directly exploitable by management systems constraining the implementation of the technology for such applications. This paper presents a new algorithm for the automatic detection of zebra crossing. The algorithm is divided in three main steps: road segmentation (based on a PCA analysis of the points contained in each cycle of collected by a mobile laser system), rasterization (conversion of the point cloud to a raster image coloured as a function of intensity data), and zebra crossing detection (using the Hough Transform and logical constrains for line classification). After evaluating different datasets collected in three cities located in Northwest Spain (comprising 25 strips with 30 visible zebra crossings) a completeness of 83% was achieved.
A SEMI-AUTOMATIC PROCEDURE FOR TEXTURING OF LASER SCANNING POINT CLOUDS WITH GOOGLE STREETVIEW IMAGES
Authors: Lichtenauer J. F. , Sirmacek B.
Published: August 2015

Abstract. We introduce a method to texture 3D urban models with photographs that even works for Google Streetview images and can be done with currently available free software. This allows realistic texturing, even when it is not possible or cost-effective to (re)visit a scanned site to take textured scans or photographs. Mapping a photograph onto a 3D model requires knowledge of the intrinsic and extrinsic camera parameters. The common way to obtain intrinsic parameters of a camera is by taking several photographs of a calibration object with a priori known structure. The extra challenge of using images from a database such as Google Streetview, rather than your own photographs, is that it does not allow for any controlled calibration. To overcome this limitation, we propose to calibrate the panoramic viewer of Google Streetview using Structure from Motion (SfM) on any structure of which Google Streetview offers views from multiple angles. After this, the extrinsic parameters for any other view can be calculated from 3 or more tie points between the image from Google Streetview and a 3D model of the scene. These point correspondences can either be obtained automatically or selected by manual annotation. We demonstrate how this procedure provides realistic 3D urban models in an easy and effective way, by using it to texture a publicly available point cloud from a terrestrial laser scan made in Bremen, Germany, with a screenshot from Google Streetview, after estimating the focal length from views from Paris, France.
THE ENMAP CONTEST: DEVELOPING AND COMPARING CLASSIFICATION APPROACHES FOR THE ENVIRONMENTAL MAPPING AND ANALYSIS PROGRAMME – DATASET AND FIRST RESULTS
Authors: Braun A. C. , Weinmann M. , Keller S. , Müller R. , Reinartz P. , Hinz S.
Published: August 2015

Abstract. The Environmental Mapping and Analysis Programme EnMAP is a hyperspectral satellite mission, supposed to be launched into space in the near future. EnMAP is designed to be revolutionary in terms of spectral resolution and signal-to-noise ratio. Nevertheless, it will provide a relatively high spatial resolution also. In order to exploit the capacities of this future mission, its data have been simulated by other authors in previous work. EnMAP will differ from other spaceborne and airborne hyperspectral sensors. Thus, the assumption that the standard classification algorithms from other sensors will perform best for EnMAP as well cannot by upheld since proof. Unfortunately, until today, relatively few studies have been published to investigate classification algorithms for EnMAP. Thus, the authors of this study, who have provided some insights into classifying simulated EnMAP data before, aim to encourage future studies by opening the EnMAP contest. The EnMAP contest consists in a benchmark dataset provided for algorithm development, which is presented herein. For demonstrative purposes, this report also represents two classification results which have already been realized. It furthermore provides a roadmap for other scientists interested in taking part in the EnMAP contest.
USE OF A LIGHT UAV AND PHOTOGRAMMETRIC TECHNIQUES TO STUDY THE EVOLUTION OF A LANDSLIDE IN JAÉN (SOUTHERN SPAIN)
Authors: Fernández T. , Pérez J. L. , Cardenal F. J. , López A. , Gómez J. M. , Colomo C. , Delgado J. , Sánchez M.
Published: August 2015

Abstract. This paper presents a methodology for slope instability monitoring using photogrammetric techniques with very high resolution images from an unmanned aerial vehicle (UAV). An unstable area located in La Guardia (Jaen, Southern Spain), where an active mud flow has been identified, was surveyed between 2012 and 2014 by means of four UAV flights. These surveys were also compared with those data from a previous conventional aerial photogrammetric and LiDAR survey. The UAV was an octocopter equipped with GPS, inertial units and a mirrorless interchangeable-lens camera. The flight height was 90 m, which allowed covering an area of about 250 x 100 m with a ground pixel size of 2.5 cm. The orientation of the UAV flights were carried out by means of ground control points measured with GPS, but the previous aerial photogrammetric/LiDAR flight was oriented by means of direct georeferencing with in flight positioning and inertial data, although some common ground control points were used to adjust all flights in the same reference system. The DSMs of all surveys were obtained by automatic image correlation and then the differential models were calculated, allowing estimate changes in the surface. At the same time, orthophotos were obtained so horizontal and vertical displacements between relevant points were registered. Significant displacements were observed between some campaigns (some centimeters on the vertical and meters on the horizontal). Finally, we have analyzed the relation of displacements to rainfalls in recent years in the area, finding a significant temporal correlation between the two variables.
A EUROPEAN FRAMEWORK FOR RECORDING AND SHARING DISASTER DAMAGE AND LOSS DATA
Authors: Corbane C. , De Groeve T. , Ehrlich D. , Poljansek K.
Published: August 2015

Abstract. The recently adopted ‘Sendai Framework for Action on Disaster Risk Reduction 2015-2030’ sets the goals to reduce loss of life, livelihood and critical infrastructure through enhanced national planning and international cooperation. The new Framework is expected to enhance global, regional and national efforts for building resilience to disasters, across the entire disaster management cycle (prevention, preparedness, response and early recovery). Improved monitoring and accountability frameworks, relying on harmonized disaster loss data will be required for meeting the targets and for capturing the levels of progress across different scales of governance. To overcome the problems of heterogeneous disaster data and terminologies, guidelines for reporting disaster damage and losses in a structured manner will be necessary to help national and regional bodies compile this information. In the European Union, the Member States and the European Commission worked together on the establishment of guidelines for recording and sharing disaster damage and loss data as a first step towards the development of operational indicators to translate the Sendai Framework into action. This paper describes the progress to date in setting a common framework for recording disaster damage and loss data in the European Union and identifies the challenges ahead.
UAV ONBOARD PHOTOGRAMMETRY AND GPS POSITIONNING FOR EARTHWORKS
Authors: Daakir M. , Pierrot-Deseilligny M. , Bosser P. , Pichard F. , Thom C.
Published: August 2015

Abstract. Over the last decade, Unmanned Airbone Vehicles (UAVs) have been largely used for civil applications. Airborne photogrammetry has found place in these applications not only for 3D modeling but also as a measurement tool. Vinci-Construction-Terrassement is a private company specialized in public works sector and uses airborn photogrammetry as a mapping solution and metrology investigation tool on its sites. This technology is very efficient for the calculation of stock volumes for instance, or for time tracking of specific areas with risk of landslides. The aim of the present work is to perform a direct georeferencing of images acquired by the camera leaning on an embedded GPS receiver. UAV, GPS receiver and camera used are low-cost models and therefore data processing is adapted to this particular constraint.
UAV-BASED ACQUISITION OF 3D POINT CLOUD – A COMPARISON OF A LOW-COST LASER SCANNER AND SFM-TOOLS
Authors: Mader D. , Blaskow R. , Westfeld P. , Maas H.-G.
Published: August 2015

Abstract. The Project ADFEX (Adaptive Federative 3D Exploration of Multi Robot System) pursues the goal to develop a time- and cost-efficient system for exploration and monitoring task of unknown areas or buildings. A fleet of unmanned aerial vehicles equipped with appropriate sensors (laser scanner, RGB camera, near infrared camera, thermal camera) were designed and built. A typical operational scenario may include the exploration of the object or area of investigation by an UAV equipped with a laser scanning range finder to generate a rough point cloud in real time to provide an overview of the object on a ground station as well as an obstacle map. The data about the object enables the path planning for the robot fleet. Subsequently, the object will be captured by a RGB camera mounted on the second flying robot for the generation of a dense and accurate 3D point cloud by using of structure from motion techniques. In addition, the detailed image data serves as basis for a visual damage detection on the investigated building. This paper focuses on our experience with use of a low-cost light-weight Hokuyo laser scanner onboard an UAV. The hardware components for laser scanner based 3D point cloud acquisition are discussed, problems are demonstrated and analyzed, and a quantitative analysis of the accuracy potential is shown as well as in comparison with structure from motion-tools presented.
USE OF UAS IN A HIGH MOUNTAIN LANDSCAPE: THE CASE OF GRAN SOMMETTA ROCK GLACIER (AO)
Authors: Dall’Asta E. , Delaloye R. , Diotri F. , Forlani G. , Fornari M. , Morra di Cella U. , Pogliotti P. , Roncella R. , Santise M.
Published: August 2015

Abstract. Photogrammetry has been used since long time to periodically control the evolution of landslides, either from aerial images as well as from ground. Landslides control and monitoring systems face a large variety of cases and situations: in hardly accessible environments, like glacial areas and high mountain locations, it is not simple finding a survey method and a measurement control system, which are capable to reliably assess, with low costs, the expected displacement and its accuracy. For this reason, the behaviour of these events presents the geologists and the surveyor each time with different challenges. The use of UAS (Unmanned Aerial System) represents, in this context, a recent and valid option to perform the data acquisition both in safety and quickly, avoiding hazards and risks for the operators while at the same time containing the costs. The paper presents an innovative monitoring system based on UAS-photogrammetry, GNSS survey and DSM change detection techniques to evaluate the Gran Sommetta rock glacier surface movements over the period 2012-2014. Since 2012, the surface movements of the glacier are monitored by ARPAVdA (a regional environmental protection agency) as a case study for the impact of climate change on high-mountain infrastructures. In such scenarios, in fact, a low-cost monitoring activity can provide important data to improve our knowledge about glacier dynamics connected to climate changes and to prevent risks in anthropic Alps areas. To evaluate the displacements of the rock glacier different techniques were proposed: the most reliable uses the orthophoto of the area and rely on a manual identification of corresponding features performed by a trained operator. To further limit the costs and improve the density of displacement information two automatic procedures were developed as well.
USE OF VERY HIGH-RESOLUTION AIRBORNE IMAGES TO ANALYSE 3D CANOPY ARCHITECTURE OF A VINEYARD
Authors: Burgos S. , Mota M. , Noll D. , Cannelle B.
Published: August 2015

Abstract. Differencing between green cover and grape canopy is a challenge for vigour status evaluation in viticulture. This paper presents the acquisition methodology of very high-resolution images (4 cm), using a Sensefly Swinglet CAM unmanned aerial vehicle (UAV) and their processing to construct a 3D digital surface model (DSM) for the creation of precise digital terrain models (DTM). The DTM was obtained using python processing libraries. The DTM was then subtracted to the DSM in order to obtain a differential digital model (DDM) of a vineyard. In the DDM, the vine pixels were then obtained by selecting all pixels with an elevation higher than 50 [cm] above the ground level. The results show that it was possible to separate pixels from the green cover and the vine rows. The DDM showed values between −0.1 and + 1.5 [m]. A manually delineation of polygons based on the RGB image belonging to the green cover and to the vine rows gave a highly significant differences with an average value of 1.23 [m] and 0.08 [m] for the vine and the ground respectively. The vine rows elevation is in good accordance with the topping height of the vines 1.35 [m] measured on the field. This mask could be used to analyse images of the same plot taken at different times. The extraction of only vine pixels will facilitate subsequent analyses, for example, a supervised classification of these pixels.
AIRBORNE HYPERSPECTRAL REMOTE SENSING FOR IDENTIFICATION GRASSLAND VEGETATION
Authors: Burai P. , Tomor T. , Bekő L. , Deák B.
Published: August 2015

Abstract. In our study we classified grassland vegetation types of an alkali landscape (Eastern Hungary), using different image classification methods for hyperspectral data. Our aim was to test the applicability of hyperspectral data in this complex system using various image classification methods. To reach the highest classification accuracy, we compared the performance of traditional image classifiers, machine learning algorithm, feature extraction (MNF-transformation) and various sizes of training dataset. Hyperspectral images were acquired by an AISA EAGLE II hyperspectral sensor of 128 contiguous bands (400–1000 nm), a spectral sampling of 5 nm bandwidth and a ground pixel size of 1 m. We used twenty vegetation classes which were compiled based on the characteristic dominant species, canopy height, and total vegetation cover. Image classification was applied to the original and MNF (minimum noise fraction) transformed dataset using various training sample sizes between 10 and 30 pixels. In the case of the original bands, both SVM and RF classifiers provided high accuracy for almost all classes irrespectively of the number of the training pixels. We found that SVM and RF produced the best accuracy with the first nine MNF transformed bands. Our results suggest that in complex open landscapes, application of SVM can be a feasible solution, as this method provides higher accuracies compared to RF and MLC. SVM was not sensitive for the size of the training samples, which makes it an adequate tool for cases when the available number of training pixels are limited for some classes.
USING LEGACY SOIL DATA FOR STANDARDIZING PREDICTIONS OF TOPSOIL CLAY CONTENT OBTAINED FROM VNIR/SWIR HYPERSPECTRAL AIRBORNE IMAGES
Authors: Gomez C. , Gholizadeh A. , Borůvka L. , Lagacherie P.
Published: August 2015

Abstract. Mapping of topsoil properties using Visible, Near-Infrared and Short Wave Infrared (VNIR/SWIR) hyperspectral imagery requires large sets of ground measurements for calibrating the models that estimate soil properties. To avoid collecting such expensive data, we proposed a procedure including two steps that involves only legacy soil data that were collected over and?or around the study site: 1) estimation of a soil property using a spectral index of the literature and 2) standardisation of the estimated soil property using legacy soil data. This approach was tested for mapping clay contents in a Mediterranean region in which VNIR/SWIR AISA-DUAL hyperspectral airborne data were acquired. The spectral index was the one proposed by Levin et al (2007) using the spectral bands at 2209, 2133 and 2225 nm. Two legacy soil databases were tested as inputs of the procedure: the Focused-Legacy database composed of 67 soil samples collected in 2000 over the study area, and the No-Focused-Legacy database composed of 64 soil samples collected between 1973 and 1979 around but outside of the study area. The results were compared with those obtained from 120 soil samples collected over the study area during the hyperspectral airborne data acquisition, which were considered as a reference. Our results showed that: 1) the spectral index with no further standardisation offered predictions with high accuracy in term of coefficient of correlation r (0.71), but also high bias (−414 g/kg) and SEP (439 g/kg), 2) the standardisation using both legacy soil databases allowed an increase of accuracy (r = 0.76) and a reduction of bias and SEP and 3) a better standardisation was obtained by using the Focused-Legacy database rather than the No-Focused-Legacy database. Finally, the clay predicted map obtained with standardisation using the Focused-Legacy database showed pedologically-significant soil spatial structures with clear short-scale variations of topsoil clay contents in specific areas. This study, associated with the coming availability of a next generation of hyperspectral VNIR/SWIR satellite data for the entire globe, paves the way for inexpensive methods for delivering high resolution soil properties maps.
A QUALITY ASSESSMENT METHOD FOR 3D ROAD POLYGON OBJECTS
Authors: Gao L. , Shi W. , Wan Y.
Published: August 2015

Abstract. With the development of the economy, the fast and accurate extraction of the city road is significant for GIS data collection and update, remote sensing images interpretation, mapping and spatial database updating etc. 3D GIS has attracted more and more attentions from academics, industries and governments with the increase of requirements for interoperability and integration of different sources of data. The quality of 3D geographic objects is very important for spatial analysis and decision-making. This paper presents a method for the quality assessment of the 3D road polygon objects which is created by integrating 2D Road Polygon data with LiDAR point cloud and other height information such as Spot Height data in Hong Kong Island. The quality of the created 3D road polygon data set is evaluated by the vertical accuracy, geometric and attribute accuracy, connectivity error, undulation error and completeness error and the final results are presented.
ADVANCES IN HYPERSPECTRAL AND MULTISPECTRAL IMAGE FUSION AND SPECTRAL UNMIXING
Authors: Lanaras C. , Baltsavias E. , Schindler K.
Published: August 2015

Abstract. In this work, we jointly process high spectral and high geometric resolution images and exploit their synergies to (a) generate a fused image of high spectral and geometric resolution; and (b) improve (linear) spectral unmixing of hyperspectral endmembers at subpixel level w.r.t. the pixel size of the hyperspectral image. We assume that the two images are radiometrically corrected and geometrically co-registered. The scientific contributions of this work are (a) a simultaneous approach to image fusion and hyperspectral unmixing, (b) enforcing several physically plausible constraints during unmixing that are all well-known, but typically not used in combination, and (c) the use of efficient, state-of-the-art mathematical optimization tools to implement the processing. The results of our joint fusion and unmixing has the potential to enable more accurate and detailed semantic interpretation of objects and their properties in hyperspectral and multispectral images, with applications in environmental mapping, monitoring and change detection. In our experiments, the proposed method always improves the fusion compared to competing methods, reducing RMSE between 4% and 53%.
COMPARING NATIONAL DIFFERENCES IN WHAT PEOPLE PERCEIVE TO BE THERE: MAPPING VARIATIONS IN CROWD SOURCED LAND COVER
Authors: Comber A. , Mooney P. , Purves R. S. , Rocchini D. , Walz A.
Published: August 2015

Abstract. This paper describes a simple comparison of the distributions of land cover features identified from volunteered data contributed by different social groups – in this case comparing two groups of Geo-Wiki campaigns. Understanding the impacts on analyses of citizen science data contributed by different groups is critical to ensure robust scientific outputs and to fully realise the potential benefits to formal scientific research. It is well known that different people, with different backgrounds and subject to different cultural factors, hold varying landscape conceptualisations. This paper analyses volunteered geographical information on land cover to generate land cover maps. It uses a geographically weighted approach to generate land cover mappings. The mappings generated by different groups (in this case a from a specific unnamed country) are compared and the results show how the predicted land cover distributions vary, with large differences in some classes (e.g. Barren land, Shrubland, Wetland) and little difference in others (e.g. Tree cover). This suggests that for some landscape features cultural and national differences matter when it comes to using crowdsourced data in formal scientific analyses and highlights the potential problems of not considering contributor backgrounds in citizen science. This is important because such data re now routinely being used to develop global land cover data, to generate uncertainty estimates of existing global land cover products and to generate global forest inventories. These in turn are being suggested as suitable inputs to such things as global climate models. A number of critical research directions arising from these findings are discussed.
Temporal variations in the flow of a large Antarctic ice stream controlled by tidally induced changes in the subglacial water system
Authors: Rosier S. H. R. , Gudmundsson G. H. , Green J. A. M.
Published: August 2015

Abstract. Observations show that the flow of Rutford Ice Stream (RIS) is strongly modulated by the ocean tides, with the strongest tidal response at the 14.77-day tidal period (Msf). This is striking because this period is absent in the tidal forcing. A number of mechanisms have been proposed to account for this effect, yet previous modelling studies have struggled to match the observed large amplitude and decay length scale. We use a nonlinear 3-D viscoelastic full-Stokes model of ice-stream flow to investigate this open issue. We find that the long period Msf modulation of ice-stream velocity observed in data cannot be reproduced quantitatively without including a coupling between basal sliding and tidally induced subglacial water pressure variations, transmitted through a highly conductive drainage system at low effective pressure. Furthermore, the basal sliding law requires a water pressure exponent that is strongly nonlinear with q = 10 and a nonlinear basal shear exponent of m = 3. Coupled model results show that sub-ice shelf tides result in a ∼12 % increase in mean horizontal velocity of the adjoining ice stream. Observations of tidally induced variations in flow of ice streams provide stronger constraints on basal sliding processes than provided by any other set of measurements.
ENSO influence on surface energy and mass balance at Shallap Glacier, Cordillera Blanca, Peru
Authors: Maussion F. , Gurgiser W. , Großhauser M. , Kaser G. , Marzeion B.
Published: August 2015

Abstract. The El Niño/Southern Oscillation (ENSO) is a major driver of climate variability in the tropical Andes, where recent Niño and Niña events left an observable footprint on glacier mass balance. The nature and strength of the relationship between ENSO and glacier mass balance, however, varies between regions and time periods, leaving several unanswered questions about its exact mechanisms. The starting point of this study is a 4-year long time series of distributed surface energy and mass balance (SEB/SMB) calculated using a process-based model driven by observations at Shallap Glacier (Cordillera Blanca, Peru). These data are used to calibrate a regression-based downscaling model that links the local SEB/SMB fluxes to atmospheric reanalysis variables on a monthly basis, allowing an unprecedented quantification of the ENSO influence on the SEB/SMB at climatological time scales (1980–2013, ERA-Interim period). We find a stronger and steadier anti-correlation between Pacific sea-surface temperature (SST) and glacier mass balance than previously reported. This relationship is most pronounced during the wet season (December–May) and at low altitudes where Niño (Niña) events are accompanied with a snowfall deficit (excess) and a higher (lower) radiation energy input. We detect a weaker but significant ENSO anti-correlation with total precipitation (Niño dry signal) and positive correlation with the sensible heat flux, but find no ENSO influence on sublimation. Sensitivity analyses comparing several downscaling methods and reanalysis data sets resulted in stable mass balance correlations with Pacific SST but also revealed large uncertainties in computing the mass balance trend of the last decades. The newly introduced open-source downscaling tool can be applied easily to other glaciers in the tropics, opening new research possibilities on even longer time scales.
Black carbon in snow in the upper Himalayan Khumbu Valley, Nepal: observations and modeling of the impact on snow albedo, melting, and radiative forcing
Authors: Jacobi H.-W. , Lim S. , Ménégoz M. , Ginot P. , Laj P. , Bonasoni P. , Stocchi P. , Marinoni A. , Arnaud Y.
Published: August 2015

Abstract. Black carbon (BC) in snow in the Himalayas has recently attracted considerable interest due to its impact on snow albedo, snow and glacier melting, regional climate and water resources. A single particle soot photometer (SP2) instrument was used to measure refractory BC (rBC) in a series of surface snow samples collected in the upper Khumbu Valley, Nepal between November 2009 and February 2012. The obtained time series indicates annual cycles with maximum rBC concentrations before the onset of the monsoon season and fast decreases during the monsoon period. Detected concentrations ranged from a few up to 70 ppb with rather large uncertainties due to the handling of the samples. Detailed modeling of the snowpack, including the detected range and an estimated upper limit of BC concentrations, was performed to study the role of BC in the seasonal snowpack. Simulations were performed for three winter seasons with the snowpack model Crocus, including a detailed description of the radiative transfer inside the snowpack. While the standard Crocus model strongly overestimates the height and the duration of the seasonal snowpack, a better calculation of the snow albedo with the new radiative transfer scheme enhanced the representation of the snow. However, the period with snow on the ground without BC in the snow was still overestimated between 37 and 66 days, which was further diminished by 8 to 15 % and more than 40 % in the presence of 100 or 300 ppb of BC. Compared to snow without BC, the albedo is reduced on average by 0.027 and 0.060 in the presence of 100 and 300 ppb BC. While the impact of increasing BC in the snow on the albedo was largest for clean snow, the impact on the local radiative forcing is the opposite. Here, increasing BC caused an even larger impact at higher BC concentrations. This effect is related to an accelerated melting of the snowpack caused by a more efficient metamorphism of the snow due to an increasing size of the snow grains with increasing BC concentrations. The melting of the winter snowpack was shifted by 3 to 10 and 17 to 27 days during the three winter seasons in the presence of 100 and 300 ppb BC compared to clean snow, while the simulated annual local radiative forcing corresponds to 3 to 4.5 and 10.5 to 13.0 W m−2. An increased sublimation or evaporation of the snow reduces the simulated radiative forcing, leading to a net forcing that is lower by 0.5 to 1.5 W m−2, while the addition of 10 ppm dust causes an increase of the radiative forcing between 2.5 and 3 W m−2. According to the simulations, 7.5 ppm of dust has an effect equivalent to 100 ppb of BC concerning the impact on the melting of the snowpack and the local radiative forcing.
Elonis v. United States: The Doctrine of True Threats: Protecting Our Ever-Shrinking First Amendment Rights in the New Era of Communication
Authors: Roark Mary Margaret
Published: August 2015

The First Amendment protects one of our most precious rights as citizens of the United States—the freedom of speech. Such protection has withstood the test of time, even safeguarding speech that much of the population would find distasteful. There is one form of speech which cannot be protected: the true threat. However, the definition of what constitutes a "true threat" has expanded since its inception. In the new era of communication—where most users post first and edit later—the First Amendment protection we once possessed has been eroded as more and more speech is considered proscribable as a "true threat." In order to adequately protect both the public at large and our individual right to free speech, courts should analyze a speaker’s subjective intent before labeling speech a "true threat." Though many courts have adopted an objective, reasonable listener test, the U.S. Supreme Court now has the opportunity, in deciding Elonis v. United States, to take a monumental step in protecting the First Amendment right to free speech. By holding that the speaker’s subjective intent to threaten is necessary for a true threat conviction, the Court will restore the broad protection afforded by the First Amendment and repair years of erosion caused by an objective approach.
Weaponized Police Drones and Their Effect on Police Use of Force
Authors: Stelmack Kyle
Published: August 2015

Abstract
TRACI Assessment of Transportation Manufacturing Nexus in the U.S.: A Supply Chain-linked Cradle-to-Gate LCA
Authors: Egilmez Gokhan , Park Yong
Published: August 2015

Sustainable transportation is an inevitable component of sustainable development intitiatives for mitigating the climate change impacts and stabilizing the rising carbon emissions thus global temperature. In this context, comprehensive analysis of the environmental impact of transportation can play a critical role towards quantifying the midpoint environmental and human health related impacts associated with the transportation activities triggered by manufacturing sectors. This study traces the life cycle impact of the U.S. transportation and manufacturing sectors’ nexus using Tool for the Reduction and Assessment of Chemicals and Other Environmental Impacts (TRACI) in the context of the Economic Input-Output Life Cycle Assessment (EIO-LCA) framework considering the following midpoint impact categories: ‘global warming’, ‘particulate matter’, ‘eutrophication’, ‘acidification’, and ‘smog air’. Both direct (onsite) and indirect (supply chain) industries’ relationships with transportation industry are considered as the main scope. Results indicated that top ten contributor manufacturing sectors accounted for over 55% total environmental impacts on each impact category. Additionally, based on the decomposition analysis, food manufacturing sector was found to be the major contributor to smog air with an approximate share of 21% in the entire supply chain. Automobile related manufacturing sectors also have significant impact on all five life cycle impact categories that the environmental impact of transportation is higher than on-site (direct) impact. Overall decomposition analysis of 53 manufacturing sector indicated that the environmental impact of transportation has severe effects on ‘smog air’, ‘eutrophication’ and ‘acidification’ with a share of 16.4%, 10.5%, and 6.0%, respectively. When we consider the average percentage share of transportation related environmental impact on the entire supply chain, U.S manufacturing sectors have a negative impact with a share of 18.8% of ‘smog air’, 16.8% for ‘eutrophication’, and 8.1% for ‘acidification’. 
Monseñor Romero: Un obispo sin miedo
Authors: Velásquez Valle Róger
Published: August 2015

El Rev. Róger Velázquez, pastor Bautista, comparte un testimonio de relación con el arzobispo omero, cuando se desempeñaba como pastor de la Primera Iglesia Bautista de El Salvador. Tuvo la dicha y el privilegio de conocerle y valorarle en su grandeza y humildad como siervo de Dios, en su labor pastoral al lado de los pobres y víctimas de la violencia institucionalizada que vivía ese país y su palabra profética, denunciando la injusticia y anunciando la esperanza de una nueva vida para el pueblo.
"Censura"
Authors: Chávez Daniel
Published: August 2015

De la sombra, el enigma es la luz. Daniel Chávez es un alquimista de la luz, su obra que recién empieza a madurar va sometiéndose a su ritmo, lento pero preciso, sin pretensiones pero a veces exquisito, casi imperturbable en su magia, el realismo aparece elegante y delicado. El tema femenino, el de la mujer-diosa, el de la mujer humana, el humano y su rostro, al final el ser humano. El artista en su surrealismo escueto deja claro en su discurso que no es un perpetuo relatador, a veces solo un espectador más de sí mismo RicardoMaya RodríguezArtista Plástico Cubano
"Ya hemos sembrado la semilla" del Dr. Melvin Javier Paredes
Authors: Silva Erwin
Published: August 2015

Obra publicada en ocasión del XLVII Aniversario de la Universidad Politécnica de Nicaragua-UPOLI (1967-2014) y del Centenario de la Obra Bautista en el Pacífico de Nicaragua (1917-2017). PBS UPOLI, Managua, Nicaragua, Septiembre (2014).
Voronoi Diagrams and Spring Rain
Authors: Perham Arnold E. , Perham Faustine L.
Published: August 2015

The same rain that washes out the high school baseball team's game supplies data for a class geometry project.
Technology Tips: Investigating Zeros of Cubics with GeoGebra
Authors: Miller David A.
Published: August 2015

Author uses GeoGebra to show that tangent lines at the mean of two x-intercepts of a cubic with three real roots will pass through the third x-intercept.
Sketching Up the Digital Duck
Authors: Shafer Kathryn G. , Severt Gina , Olson Zachary A.
Published: August 2015

Two preservice teachers describe how using Google SketchUp, Terrapin Logo, and The Geometer's Sketchpad fosters a deeper understanding of measurement concepts.
What Every Client Wants? (Re)mapping the Trajectory of Client Expectations Research
Authors: Downie Jonathan
Published: August 2015

Since the late 1980s, scholars have sought to understand what it is that speakers, audience members or conference organisers want from the interpreters with whom they work. The aim of this paper is to provide a critical review of the work that has taken place to understand these expectations, with a view to fostering a greater understanding of both the expectations of clients and how these expectations could be explored in a more nuanced fashion. Unlike Kurz (2001), who chose to provide an author-centred summary, publications are examined in this paper in chronological order, allowing the historical development of this area of research to be clearly seen. This structure also draws attention to the relative reduction in the number of publications on client expectations published in the first decade of the current millennium. This paper gives possible reasons for this reduction in publication frequency, followed by a detailed exploration of how more recent publications in this area differ from those published in earlier periods. These differences, and most notably the move towards dividing expectations into different categories, representing stereotypical and event-specific requirements of interpreters, are presented as offering a valuable starting point for future research.