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Volume 5
Issue 12
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ISPRS Int. J. Geo-Inf., Volume 5, Issue 12 (December 2016) – 29 articles

Cover Story (view full-size image): The causes of VGI imprecision and uncertainty in citizen science projects are investigated supported by an experience within a case study in agriculture: “contextualized VGI” about in situ observations of crops is created by means of a smart app that aids volunteers by providing both their viewpoint direction and an agronomic ontology. Furthermore, fuzzy domain ontologies are proposed for creating VGI in the cases of ill-defined domain knowledge; and level-based approximate reasoning is suggested for allowing VGI consumers to filter VGI that satisfies their quality needs.
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3964 KiB  
Article
Efficient Processing of Continuous Reverse k Nearest Neighbor on Moving Objects in Road Networks
by Muhammad Attique, Hyung-Ju Cho, Rize Jin and Tae-Sun Chung
ISPRS Int. J. Geo-Inf. 2016, 5(12), 247; https://doi.org/10.3390/ijgi5120247 - 20 Dec 2016
Cited by 4 | Viewed by 4083
Abstract
A reverse k nearest neighbor (RkNN) query retrieves all the data points that have q as one of their k closest points. In recent years, considerable research has been conducted into monitoring reverse k nearest neighbor queries. In this paper, we [...] Read more.
A reverse k nearest neighbor (RkNN) query retrieves all the data points that have q as one of their k closest points. In recent years, considerable research has been conducted into monitoring reverse k nearest neighbor queries. In this paper, we study the problem of continuous reverse nearest neighbor queries where both the query object q and data objects are moving. Existing state-of-the-art techniques are sensitive towards the movement of data objects, e.g., a candidate object must be verified whenever it changes its location. Further, insufficient attention has been given to the monitoring of RNN queries in dynamic road networks where the network weight changes depending on the traffic conditions. In this paper, we address these problems by proposing a new safe exit-based algorithm called CORE-X for efficiently computing the safe exit points of both query and data objects. The safe exit point of an object indicates the point at which its safe region and non-safe region meet, thus a set of safe exit points represents the border of the safe region. Within the safe region, the query result remains unchanged provided the query and data objects remain inside their respective safe regions. The results of extensive experiments conducted using real road maps indicate that the proposed algorithm significantly reduces communication and computation costs compared to the state-of-the-art algorithm. Full article
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Article
A Line Graph-Based Continuous Range Query Method for Moving Objects in Networks
by Hengcai Zhang, Feng Lu and Jie Chen
ISPRS Int. J. Geo-Inf. 2016, 5(12), 246; https://doi.org/10.3390/ijgi5120246 - 19 Dec 2016
Cited by 5 | Viewed by 4469
Abstract
The rapid growth of location-based services has motivated the development of continuous range queries in networks. Existing query algorithms usually adopt an expansion tree to reuse the previous query results to get better efficiency. However, the high maintenance costs of the traditional expansion [...] Read more.
The rapid growth of location-based services has motivated the development of continuous range queries in networks. Existing query algorithms usually adopt an expansion tree to reuse the previous query results to get better efficiency. However, the high maintenance costs of the traditional expansion tree lead to a sharp efficiency decrease. In this paper, we propose a line graph-based continuous range (LGCR) query algorithm for moving objects in networks, which is characterized by a novel graph-based expansion tree (GET) structure used to monitor queries in an incremental manner. In particular, GET is developed based on the line graph model of networks and simultaneously supports offline pre-computation to better adapt our proposed algorithm to different sizes of networks. To improve performance, we create a series of related data structures, such as bridgeable edges and distance edges. Correspondingly, we develop several algorithms, including initialization, insertion of objects, filter and refinement and location update, to incrementally re-evaluate continuous range queries. Finally, we implement the GET and related algorithms in the native graph database Neo4J. We conduct experiments using real-world networks and simulated moving objects and compare the proposed LGCR with the existing classical algorithm to verify its effectiveness and demonstrate its greater efficiency. Full article
(This article belongs to the Special Issue Location-Based Services)
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Article
Interest Aware Location-Based Recommender System Using Geo-Tagged Social Media
by Basma AlBanna, Mahmoud Sakr, Sherin Moussa and Ibrahim Moawad
ISPRS Int. J. Geo-Inf. 2016, 5(12), 245; https://doi.org/10.3390/ijgi5120245 - 19 Dec 2016
Cited by 19 | Viewed by 6128
Abstract
Advances in location acquisition and mobile technologies led to the addition of the location dimension to Social Networks (SNs) and to the emergence of a newer class called Location-Based Social Networks (LBSNs). While LBSNs are richer in their model and functions than SNs, [...] Read more.
Advances in location acquisition and mobile technologies led to the addition of the location dimension to Social Networks (SNs) and to the emergence of a newer class called Location-Based Social Networks (LBSNs). While LBSNs are richer in their model and functions than SNs, they fail so far to attract as many users as SNs. On the other hand, SNs have large amounts of geo-tagged media that are under-utilized. In this paper, we propose an Interest-Aware Location-Based Recommender system (IALBR), which combines the advantages of both LBSNs and SNs, in order to provide interest-aware location-based recommendations. This recommender system is proposed as an extension to LBSNs. It is novel in: (1) utilizing the geo-content in both LBSNs and SNs; (2) ranking the recommendations based on a novel scoring method that maps to the user interests. It also works for passive users who are not active content contributors to the LBSN. This feature is critical to increase the number of LBSN users. Moreover, it helps with reducing the cold start problem, which is a common problem facing the new users of recommender systems who get random unsatisfying recommendations. This is due to the lack of user interest awareness, which is reliant on user history in most of the recommenders. We evaluated our system with a large-scale real dataset collected from foursquare with respect to precision, recall and the f-measure. We also compared the results with a ground truth system using metrics like the normalized discounted cumulative gain and the mean absolute error. The results confirm that the proposed IALBR generates more efficient recommendations than baselines in terms of interest awareness. Full article
(This article belongs to the Special Issue Location-Based Services)
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Article
Automatic Pose Estimation of Uncalibrated Multi-View Images Based on a Planar Object with a Predefined Contour Model
by Cailin Li, Langming Zhou and Wenhe Chen
ISPRS Int. J. Geo-Inf. 2016, 5(12), 244; https://doi.org/10.3390/ijgi5120244 - 16 Dec 2016
Cited by 2 | Viewed by 5547
Abstract
We have presented a framework to obtain camera pose (i.e., position and orientation in the 3D space) with real scale information of the uncalibrated multi-view images and the intrinsic camera parameters automatically. Our framework consists of two key steps. First, the initial value [...] Read more.
We have presented a framework to obtain camera pose (i.e., position and orientation in the 3D space) with real scale information of the uncalibrated multi-view images and the intrinsic camera parameters automatically. Our framework consists of two key steps. First, the initial value of the intrinsic camera and the pose parameters were extracted from homography estimation based on the contour model of some planar objects. Second, a refinement of the intrinsic camera and pose parameters was operated by the bundle adjustment procedure. Our framework can provide a complete flow of pose estimation of disorderly or orderly uncalibrated multi-view images, which can be used in vision tasks requiring scale information. Real multi-view images were utilized to demonstrate the robustness, flexibility and accuracy of the proposed framework. The proposed framework was also applied in 3D reconstruction. Full article
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Article
Simulation of Dynamic Urban Growth with Partial Least Squares Regression-Based Cellular Automata in a GIS Environment
by Yongjiu Feng, Miaolong Liu, Lijun Chen and Yu Liu
ISPRS Int. J. Geo-Inf. 2016, 5(12), 243; https://doi.org/10.3390/ijgi5120243 - 16 Dec 2016
Cited by 21 | Viewed by 5826
Abstract
We developed a geographic cellular automata (CA) model based on partial least squares (PLS) regression (termed PLS-CA) to simulate dynamic urban growth in a geographical information systems (GIS) environment. The PLS method extends multiple linear regression models that are used to define the [...] Read more.
We developed a geographic cellular automata (CA) model based on partial least squares (PLS) regression (termed PLS-CA) to simulate dynamic urban growth in a geographical information systems (GIS) environment. The PLS method extends multiple linear regression models that are used to define the unique factors driving urban growth by eliminating multicollinearity among the candidate drivers. The key factors (the spatial variables) extracted are uncorrelated, resulting in effective transition rules for urban growth modeling. The PLS-CA model was applied to simulate the rapid urban growth of Songjiang District, an outer suburb in the Shanghai Municipality of China from 1992 to 2008. Among the three components acquired by PLS, the first two explained more than 95% of the total variance. The results showed that the PLS-CA simulated pattern of urban growth matched the observed pattern with an overall accuracy of 85.8%, as compared with 83.5% of a logistic-regression-based CA model for the same area. The PLS-CA model is readily applicable to simulations of urban growth in other rapidly urbanizing areas to generate realistic land use patterns and project future scenarios. Full article
(This article belongs to the Special Issue Advances and Innovations in Land Use/Cover Mapping)
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9356 KiB  
Article
Detection of Catchment-Scale Gully-Affected Areas Using Unmanned Aerial Vehicle (UAV) on the Chinese Loess Plateau
by Kai Liu, Hu Ding, Guoan Tang, Jiaming Na, Xiaoli Huang, Zhengguang Xue, Xin Yang and Fayuan Li
ISPRS Int. J. Geo-Inf. 2016, 5(12), 238; https://doi.org/10.3390/ijgi5120238 - 16 Dec 2016
Cited by 60 | Viewed by 7406
Abstract
The Chinese Loess Plateau suffers from serious gully erosion induced by natural and human causes. Gully-affected areas detection is the basic work in this region for gully erosion assessment and monitoring. For the first time, an unmanned aerial vehicle (UAV) was applied to [...] Read more.
The Chinese Loess Plateau suffers from serious gully erosion induced by natural and human causes. Gully-affected areas detection is the basic work in this region for gully erosion assessment and monitoring. For the first time, an unmanned aerial vehicle (UAV) was applied to extract gully features in this region. Two typical catchments in Changwu and Ansai were selected to represent loess tableland and loess hilly regions, respectively. A high-powered quadrocopter (md4-1000) equipped with a non-metric camera was used for image acquisition. InPho and MapMatrix were applied for semi-automatic workflow including aerial triangulation and model generation. Based on the stereo-imaging and the ground control points, the highly detailed digital elevation models (DEMs) and ortho-mosaics were generated. Subsequently, an object-based approach combined with the random forest classifier was designed to detect gully-affected areas. Two experiments were conducted to investigate the influences of segmentation strategy and feature selection. Results showed that vertical and horizontal root-mean-square errors were below 0.5 and 0.2 m, respectively, which were ideal for the Loess Plateau region. The overall extraction accuracy in Changwu and Ansai achieved was 84.62% and 86.46%, respectively, which indicated the potential of the proposed workflow for extracting gully features. This study demonstrated that UAV can bridge the gap between field measurement and satellite-based remote sensing, obtaining a balance in resolution and efficiency for catchment-scale gully erosion research. Full article
(This article belongs to the Special Issue Advances in Geo-Information for Environmental Forensics and Environmental Risk Management in the Anthropocene)
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3063 KiB  
Article
Integrating Multiple Spatial Datasets to Assess Protected Areas: Lessons Learnt from the Digital Observatory for Protected Areas (DOPA)
by Grégoire Dubois, Lucy Bastin, Bastian Bertzky, Andrea Mandrici, Michele Conti, Santiago Saura, Andrew Cottam, Luca Battistella, Javier Martínez-López, Martino Boni and Mariagrazia Graziano
ISPRS Int. J. Geo-Inf. 2016, 5(12), 242; https://doi.org/10.3390/ijgi5120242 - 15 Dec 2016
Cited by 14 | Viewed by 6753
Abstract
The Digital Observatory for Protected Areas (DOPA) has been developed to support the European Union’s efforts in strengthening our capacity to mobilize and use biodiversity data so that they are readily accessible to policymakers, managers, researchers and other users. Assessing protected areas for [...] Read more.
The Digital Observatory for Protected Areas (DOPA) has been developed to support the European Union’s efforts in strengthening our capacity to mobilize and use biodiversity data so that they are readily accessible to policymakers, managers, researchers and other users. Assessing protected areas for biodiversity conservation at national, regional and international scales implies that methods and tools are in place to evaluate characteristics such as the protected areas’ connectivity, their species assemblages (including the presence of threatened species), the uniqueness of their ecosystems, and the threats these areas are exposed to. Typical requirements for such analyses are data on protected areas, information on species distributions and threat status, and information on ecosystem distributions. By integrating all these global data consistently in metrics and indicators, the DOPA provides the means to allow end-users to evaluate protected areas individually but also to compare protected areas at the country and ecoregion level to, for example, identify potential priorities for further conservation research, action and funding. Since the metrics and indicators are available through web services, the DOPA further allows end-users to develop their own applications without requiring management of large databases and processing capacities. In addition to examples illustrating how the DOPA can be used as an aid to decision making, we discuss the lessons learnt in the development of this global biodiversity information system, and outline planned future developments for further supporting conservation strategies. Full article
(This article belongs to the Special Issue Spatial Ecology)
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Article
Discovery of Transition Rules for Cellular Automata Using Artificial Bee Colony and Particle Swarm Optimization Algorithms in Urban Growth Modeling
by Fereydoun Naghibi and Mahmoud Reza Delavar
ISPRS Int. J. Geo-Inf. 2016, 5(12), 241; https://doi.org/10.3390/ijgi5120241 - 15 Dec 2016
Cited by 9 | Viewed by 5311
Abstract
This paper presents an advanced method in urban growth modeling to discover transition rules of cellular automata (CA) using the artificial bee colony (ABC) optimization algorithm. Also, comparisons between the simulation results of CA models optimized by the ABC algorithm and the particle [...] Read more.
This paper presents an advanced method in urban growth modeling to discover transition rules of cellular automata (CA) using the artificial bee colony (ABC) optimization algorithm. Also, comparisons between the simulation results of CA models optimized by the ABC algorithm and the particle swarm optimization algorithms (PSO) as intelligent approaches were performed to evaluate the potential of the proposed methods. According to previous studies, swarm intelligence algorithms for solving optimization problems such as discovering transition rules of CA in land use change/urban growth modeling can produce reasonable results. Modeling of urban growth as a dynamic process is not straightforward because of the existence of nonlinearity and heterogeneity among effective involved variables which can cause a number of challenges for traditional CA. ABC algorithm, the new powerful swarm based optimization algorithms, can be used to capture optimized transition rules of CA. This paper has proposed a methodology based on remote sensing data for modeling urban growth with CA calibrated by the ABC algorithm. The performance of ABC-CA, PSO-CA, and CA-logistic models in land use change detection is tested for the city of Urmia, Iran, between 2004 and 2014. Validations of the models based on statistical measures such as overall accuracy, figure of merit, and total operating characteristic were made. We showed that the overall accuracy of the ABC-CA model was 89%, which was 1.5% and 6.2% higher than those of the PSO-CA and CA-logistic model, respectively. Moreover, the allocation disagreement (simulation error) of the simulation results for the ABC-CA, PSO-CA, and CA-logistic models are 11%, 12.5%, and 17.2%, respectively. Finally, for all evaluation indices including running time, convergence capability, flexibility, statistical measurements, and the produced spatial patterns, the ABC-CA model performance showed relative improvement and therefore its superiority was confirmed. Full article
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Article
Portraying Temporal Dynamics of Urban Spatial Divisions with Mobile Phone Positioning Data: A Complex Network Approach
by Meng Zhou, Yang Yue, Qingquan Li and Donggen Wang
ISPRS Int. J. Geo-Inf. 2016, 5(12), 240; https://doi.org/10.3390/ijgi5120240 - 13 Dec 2016
Cited by 31 | Viewed by 7345
Abstract
Spatial structure is a fundamental characteristic of cities that influences the urban functioning to a large extent. While administrative partitioning is generally done in the form of static spatial division, understanding a more temporally dynamic structure of the urban space would benefit urban [...] Read more.
Spatial structure is a fundamental characteristic of cities that influences the urban functioning to a large extent. While administrative partitioning is generally done in the form of static spatial division, understanding a more temporally dynamic structure of the urban space would benefit urban planning and management immensely. This study makes use of a large-scale mobile phone positioning dataset to characterize the diurnal dynamics of the interaction-based urban spatial structure. To extract the temporally vibrant structure, spatial interaction networks at different times are constructed based on the movement connections of individuals between geographical units. Complex network community detection technique is applied to identify the spatial divisions as well as to quantify their temporal dynamics. Empirical analysis is conducted using data containing all user positions on a typical weekday in Shenzhen, China. Results are compared with official zoning and planned structure and indicate a certain degree of expansion in urban central areas and fragmentation in industrial suburban areas. A high level of variability in spatial divisions at different times of day is detected with some distinct temporal features. Peak and pre-/post-peak hours witness the most prominent fluctuation in spatial division indicating significant change in the characteristics of movements and activities during these periods of time. Findings of this study demonstrate great potential of large-scale mobility data in supporting intelligent spatial decision making and providing valuable knowledge to the urban planning sectors. Full article
(This article belongs to the Special Issue Intelligent Spatial Decision Support)
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3257 KiB  
Article
Typification for Façade Structures Based on User Perception
by Jie Shen, Hongchao Fan, Bo Mao and Menghe Wang
ISPRS Int. J. Geo-Inf. 2016, 5(12), 239; https://doi.org/10.3390/ijgi5120239 - 9 Dec 2016
Cited by 7 | Viewed by 5126
Abstract
Typification is a well-established operator of map generalization. Although it is widely used in many existing research fields, less discussion has been devoted to the quality of typification. This paper presents a user survey for the evaluation of different typification results of façade [...] Read more.
Typification is a well-established operator of map generalization. Although it is widely used in many existing research fields, less discussion has been devoted to the quality of typification. This paper presents a user survey for the evaluation of different typification results of façade structures under different constraints. The survey shows that preservation of the shape of the features is the most important constraint for a reasonable typification process, which has also been quantitatively verified by calculating the similarities between the typified façades and the original façade using attributed relational graph (ARG) and nested earth mover’s distance (NEMD) algorithms. Based on that, an algorithm is developed to generate perceivably reasonable representation from the original facade with decreasing map scale. The algorithm is implemented and tested on a number of façades. Experiments reveal that the typification can be automatically conducted and can create results which are well associated with the original façades. Full article
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Article
Observational Analysis of Variation Characteristics of GPS-Based TEC Fluctuation over China
by Xifeng Liu, Yunbin Yuan, Bingfeng Tan and Min Li
ISPRS Int. J. Geo-Inf. 2016, 5(12), 237; https://doi.org/10.3390/ijgi5120237 - 8 Dec 2016
Cited by 17 | Viewed by 4823
Abstract
In this study, the characteristics of the total electron content (TEC) fluctuations and their regional differences over China were analyzed by utilizing the rate of the TEC index (ROTI) based on GPS data from 21 reference stations across China during a solar cycle. [...] Read more.
In this study, the characteristics of the total electron content (TEC) fluctuations and their regional differences over China were analyzed by utilizing the rate of the TEC index (ROTI) based on GPS data from 21 reference stations across China during a solar cycle. The results show that there were significant regional differences at different latitudes. Strong ionospheric TEC fluctuations were usually observed at lower latitudes in southern China, where the occurrence of TEC fluctuations demonstrated typical nighttime- and season-dependent (equinox months) features. This phenomenon was consistent with the ionospheric scintillation characteristics of this region. Additionally, compared to low-latitude China, the intensity of TEC fluctuations over mid-latitude China was significantly weaker, and the occurrence of TEC fluctuations was not a nighttime-dependent phenomenon. Moreover, the intensity of TEC fluctuations was much stronger during high solar activity than during low solar activity. Furthermore, the summer-dependent characteristics of TEC fluctuations gradually emerged over lower mid-latitude areas as equinox characteristics weakened. Similar to the equinox characteristics, the summer-dependent characteristics gradually weakened or even disappeared with the increasing latitude. Relevant discussions of this phenomenon are still relatively rare, and it requires further study and analysis. Full article
(This article belongs to the Special Issue Recent Advances in Geodesy & Its Applications)
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Article
Dam Deformation Monitoring Data Analysis Using Space-Time Kalman Filter
by Wujiao Dai, Ning Liu, Rock Santerre and Jiabao Pan
ISPRS Int. J. Geo-Inf. 2016, 5(12), 236; https://doi.org/10.3390/ijgi5120236 - 8 Dec 2016
Cited by 20 | Viewed by 6349
Abstract
Noise filtering, data predicting, and unmonitored data interpolating are important to dam deformation data analysis. However, traditional methods generally process single point monitoring data separately, without considering the spatial correlation between points. In this paper, the Space-Time Kalman Filter (STKF), a dynamic spatio-temporal [...] Read more.
Noise filtering, data predicting, and unmonitored data interpolating are important to dam deformation data analysis. However, traditional methods generally process single point monitoring data separately, without considering the spatial correlation between points. In this paper, the Space-Time Kalman Filter (STKF), a dynamic spatio-temporal filtering model, is used as a spatio-temporal data analysis method for dam deformation. There were three main steps in the method applied in this paper. The first step was to determine the Kriging spatial fields based on the characteristics of dam deformation. Next, the observation noise covariance, system noise covariance, the initial mean vector state, and its covariance were estimated using the Expectation Maximization algorithm (EM algorithm) in the second step. In the third step, we filtered the observation noise, interpolated the whole dam unmonitored data in space and time domains, and predicted the deformation for the whole dam using the Kalman filter recursion algorithm. The simulation data and Wuqiangxi dam deformation monitoring data were used to verify the STKF method. The results show that the STKF not only can filter the deformation data noise in both the temporal and spatial domain effectively, but also can interpolate and predict the deformation for the whole dam. Full article
(This article belongs to the Special Issue Recent Advances in Geodesy & Its Applications)
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Article
Past and Future Spatial Growth Dynamics of Chihuahua City, Mexico: Pressures for Land Use
by Jesús A. Prieto-Amparán, Alfredo Pinedo-Alvarez, Federico Villarreal-Guerrero, Carmelo Pinedo-Alvarez, Carlos Morales-Nieto and Carlos Manjarrez-Domínguez
ISPRS Int. J. Geo-Inf. 2016, 5(12), 235; https://doi.org/10.3390/ijgi5120235 - 8 Dec 2016
Cited by 9 | Viewed by 5676
Abstract
In this study, the transitions of land use that occurred in the urban and peripheral areas of Chihuahua City, Mexico, were determined for the period 1989–2014. Landsat TM and OLI scenes, as well as the method of Markov Chains (MC) were used. Grasslands [...] Read more.
In this study, the transitions of land use that occurred in the urban and peripheral areas of Chihuahua City, Mexico, were determined for the period 1989–2014. Landsat TM and OLI scenes, as well as the method of Markov Chains (MC) were used. Grasslands and Shrublands were the land uses that experienced the highest pressures for land use. Grasslands occupied 23.5% of the area in 1989, decreasing to 16.01% in 2014. Likewise, Shrublands were reduced from 54.53% to 48.06%. The areas occupied by Croplands, Oak forest, Water bodies and Riparian vegetation stayed in general constant. In contrast, the urban area increased from 13.6% to 28.6% of the total area studied. In addition, projections of land use for 2019 and 2024 were generated through the method of MC and Cellular Automata (CA). According to the projections, validated with an agreement of 0.90, the Human settlements would continue to expand, occupying 38.57% by 2019 and almost half of the studied territory (47.33%) by 2024. The ecosystems with the highest pressure for land use change will continue to be the Grasslands and Shrublands. By 2024, the former would lose 15.8% while the latter would lose 16.7% of the area. These methods are valuable for urban planning and the results could support growth plans for Chihuahua City, Mexico, with a sustainable approach. Full article
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Article
“Contextualized VGI” Creation and Management to Cope with Uncertainty and Imprecision
by Gloria Bordogna, Luca Frigerio, Tomáš Kliment, Pietro Alessandro Brivio, Laure Hossard, Giacinto Manfron and Simone Sterlacchini
ISPRS Int. J. Geo-Inf. 2016, 5(12), 234; https://doi.org/10.3390/ijgi5120234 - 8 Dec 2016
Cited by 9 | Viewed by 5017
Abstract
This paper investigates the causes of imprecision of the observations and uncertainty of the authors who create Volunteer Geographic Information (VGI), i.e., georeferenced contents generated by volunteers when participating in some citizen science project. Specifically, various aspects of imprecision and uncertainty of VGI [...] Read more.
This paper investigates the causes of imprecision of the observations and uncertainty of the authors who create Volunteer Geographic Information (VGI), i.e., georeferenced contents generated by volunteers when participating in some citizen science project. Specifically, various aspects of imprecision and uncertainty of VGI are outlined and, to cope with them, a knowledge-based approach is suggested based on the creation and management of “contextualized VGI”. A case study example in agriculture is reported where contextualized VGI can be created about in situ crops observations by the use of a smart app that supports volunteers by means of both an ontology and the representation of the context of the geo-localization. Furthermore, an approach to cope with both ill-defined knowledge and volunteer’s uncertainty or imprecise observations is defined based on a fuzzy ontology with uncertainty level-based approximate reasoning. By representing uncertainty and imprecision of VGI, users, i.e., consumers, can exploit quality checking mechanisms to filter VGI based on their needs. Full article
(This article belongs to the Special Issue Volunteered Geographic Information)
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Article
A Global Inventory of Urban Corridors Based on Perceptions and Night-Time Light Imagery
by Isabel Georg, Thomas Blaschke and Hannes Taubenböck
ISPRS Int. J. Geo-Inf. 2016, 5(12), 233; https://doi.org/10.3390/ijgi5120233 - 7 Dec 2016
Cited by 15 | Viewed by 7886
Abstract
The massive growth of some urban areas has led to new constellations of urban forms. New concepts describing large urban areas have been introduced but are not always defined and mapped sufficiently and consistently. This article describes urban corridors as an example of [...] Read more.
The massive growth of some urban areas has led to new constellations of urban forms. New concepts describing large urban areas have been introduced but are not always defined and mapped sufficiently and consistently. This article describes urban corridors as an example of such a concept with an ambiguous spatial definition. Based on the existing usage of the concept in scientific literature and the results of a questionnaire, we attempt to spatially parameterize and identify the main characteristics of urban corridors on a global scale. The parameters we use are physically measurable and therefore serve as a basis for a harmonized and scientifically sound mapping of urban corridors using remote sensing data and methods. Our results are presented in a global urban corridor map. Full article
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Article
Evaluation of River Network Generalization Methods for Preserving the Drainage Pattern
by Ling Zhang and Eric Guilbert
ISPRS Int. J. Geo-Inf. 2016, 5(12), 230; https://doi.org/10.3390/ijgi5120230 - 6 Dec 2016
Cited by 12 | Viewed by 9308
Abstract
The drainage pattern of a river network is the arrangement in which a stream erodes the channels of its network of tributaries. It can reflect the geographical characteristics of a river network to a certain extent because it depends on the topography and [...] Read more.
The drainage pattern of a river network is the arrangement in which a stream erodes the channels of its network of tributaries. It can reflect the geographical characteristics of a river network to a certain extent because it depends on the topography and geology of the land and as such should be considered during the river network generalization process. There are many methods for river network generalization in tributary selection but most do not explicitly consider the network pattern. Validation of the generalized result is performed visually by an expert and may not be done systematically. An automatic validation technique may help to better understand the results obtained with each method and check whether the pattern has been preserved. This paper proposes an approach to evaluate the quality of a generalized river network by assessing how well its original drainage pattern is preserved. The membership to a drainage pattern is evaluated by a set of geometric indicators, making use of a fuzzy logic approach which allows for a compromise between different criteria depending on the membership values. Three tributary selection methods are tested in this work: selection by stroke and length, catchment area, and a manually generalized network. Assessing the quality of a generalization is done by comparing pattern memberships before and after generalization. This research provides a quantitative indicator to assess the generalized river network in preserving geographical information. Full article
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Article
Tagging in Volunteered Geographic Information: An Analysis of Tagging Practices for Cities and Urban Regions in OpenStreetMap
by Nikola Davidovic, Peter Mooney, Leonid Stoimenov and Marco Minghini
ISPRS Int. J. Geo-Inf. 2016, 5(12), 232; https://doi.org/10.3390/ijgi5120232 - 5 Dec 2016
Cited by 29 | Viewed by 7937
Abstract
In Volunteered Geographic Information (VGI) projects, the tagging or annotation of objects is usually performed in a flexible and non-constrained manner. Contributors to a VGI project are normally free to choose whatever tags they feel are appropriate to annotate or describe a particular [...] Read more.
In Volunteered Geographic Information (VGI) projects, the tagging or annotation of objects is usually performed in a flexible and non-constrained manner. Contributors to a VGI project are normally free to choose whatever tags they feel are appropriate to annotate or describe a particular geographic object or place. In OpenStreetMap (OSM), the Map Features part of the OSM Wiki serves as the de-facto rulebook or ontology for the annotation of features in OSM. Within Map Features, suggestions and guidance on what combinations of tags to use for certain geographic objects are outlined. In this paper, we consider these suggestions and recommendations and analyse the OSM database for 40 cities around the world to ascertain if contributors to OSM in these urban areas are using this guidance in their tagging practices. Overall, we find that compliance with the suggestions and guidance in Map Features is generally average or poor. This leads us to conclude that contributors in these areas do not always tag features with the same level of annotation. Our paper also confirms anecdotal evidence that OSM Map Features is less influential in how OSM contributors tag objects. Full article
(This article belongs to the Special Issue Volunteered Geographic Information)
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5860 KiB  
Article
Extraction and Simplification of Building Façade Pieces from Mobile Laser Scanner Point Clouds for 3D Street View Services
by Yan Li, Qingwu Hu, Meng Wu, Jianming Liu and Xuan Wu
ISPRS Int. J. Geo-Inf. 2016, 5(12), 231; https://doi.org/10.3390/ijgi5120231 - 5 Dec 2016
Cited by 23 | Viewed by 6966
Abstract
Extraction and analysis of building façades are key processes in the three-dimensional (3D) building reconstruction and realistic geometrical modeling of the urban environment, which includes many applications, such as smart city management, autonomous navigation through the urban environment, fly-through rendering, 3D street view, [...] Read more.
Extraction and analysis of building façades are key processes in the three-dimensional (3D) building reconstruction and realistic geometrical modeling of the urban environment, which includes many applications, such as smart city management, autonomous navigation through the urban environment, fly-through rendering, 3D street view, virtual tourism, urban mission planning, etc. This paper proposes a building facade pieces extraction and simplification algorithm based on morphological filtering with point clouds obtained by a mobile laser scanner (MLS). First, this study presents a point cloud projection algorithm with high-accuracy orientation parameters from the position and orientation system (POS) of MLS that can convert large volumes of point cloud data to a raster image. Second, this study proposes a feature extraction approach based on morphological filtering with point cloud projection that can obtain building facade features in an image space. Third, this study designs an inverse transformation of point cloud projection to convert building facade features from an image space to a 3D space. A building facade feature with restricted facade plane detection algorithm is implemented to reconstruct façade pieces for street view service. The results of building facade extraction experiments with large volumes of point cloud from MLS show that the proposed approach is suitable for various types of building facade extraction. The geometric accuracy of building façades is 0.66 m in x direction, 0.64 in y direction and 0.55 m in the vertical direction, which is the same level as the space resolution (0.5 m) of the point cloud. Full article
(This article belongs to the Special Issue Mathematical Morphology in Geoinformatics)
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687 KiB  
Article
Describing Geospatial Assets in the Web of Data: A Metadata Management Scenario
by Cristiano Fugazza, Monica Pepe, Alessandro Oggioni, Paolo Tagliolato, Fabio Pavesi and Paola Carrara
ISPRS Int. J. Geo-Inf. 2016, 5(12), 229; https://doi.org/10.3390/ijgi5120229 - 2 Dec 2016
Cited by 9 | Viewed by 4715
Abstract
Metadata management is an essential enabling factor for geospatial assets because discovery, retrieval, and actual usage of the latter are tightly bound to the quality of these descriptions. Unfortunately, the multi-faceted landscape of metadata formats, requirements, and conventions makes it difficult to identify [...] Read more.
Metadata management is an essential enabling factor for geospatial assets because discovery, retrieval, and actual usage of the latter are tightly bound to the quality of these descriptions. Unfortunately, the multi-faceted landscape of metadata formats, requirements, and conventions makes it difficult to identify editing tools that can be easily tailored to the specificities of a given project, workgroup, and Community of Practice. Our solution is a template-driven metadata editing tool that can be customised to any XML-based schema. Its output is constituted by standards-compliant metadata records that also have a semantics-aware counterpart eliciting novel exploitation techniques. Moreover, external data sources can easily be plugged in to provide autocompletion functionalities on the basis of the data structures made available on the Web of Data. Beside presenting the essentials on customisation of the editor by means of two use cases, we extend the methodology to the whole life cycle of geospatial metadata. We demonstrate the novel capabilities enabled by RDF-based metadata representation with respect to traditional metadata management in the geospatial domain. Full article
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1257 KiB  
Article
Retrieval of Remote Sensing Images with Pattern Spectra Descriptors
by Petra Bosilj, Erchan Aptoula, Sébastien Lefèvre and Ewa Kijak
ISPRS Int. J. Geo-Inf. 2016, 5(12), 228; https://doi.org/10.3390/ijgi5120228 - 2 Dec 2016
Cited by 47 | Viewed by 5369
Abstract
The rapidly increasing volume of visual Earth Observation data calls for effective content based image retrieval solutions, specifically tailored for their high spatial resolution and heterogeneous content. In this paper, we address this issue with a novel local implementation of the well-known morphological [...] Read more.
The rapidly increasing volume of visual Earth Observation data calls for effective content based image retrieval solutions, specifically tailored for their high spatial resolution and heterogeneous content. In this paper, we address this issue with a novel local implementation of the well-known morphological descriptors called pattern spectra. They are computationally efficient histogram-like structures describing the global distribution of arbitrarily defined attributes of connected image components. Besides employing pattern spectra for the first time in this context, our main contribution lies in their dense calculation, at a local scale, thus enabling their combination with sophisticated visual vocabulary strategies. The Merced Landuse/Landcover dataset has been used for comparing the proposed strategy against alternative global and local content description methods, where the introduced approach is shown to yield promising performances. Full article
(This article belongs to the Special Issue Mathematical Morphology in Geoinformatics)
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1215 KiB  
Article
Closing the Skill Gap of Cloud CRM Application Services in Cloud Computing for Evaluating Big Data Solutions
by You-Shyang Chen, Chien-Ku Lin and Huan-Ming Chuang
ISPRS Int. J. Geo-Inf. 2016, 5(12), 227; https://doi.org/10.3390/ijgi5120227 - 2 Dec 2016
Cited by 6 | Viewed by 5272
Abstract
Information systems (IS) continually motivate various improvements in the state-of-the-art of issues and solutions for advanced geo-information technologies in cloud computing. Reducing IS project risks and improving organizational performance has become an important issue. This study proposes a research framework, constructed from the [...] Read more.
Information systems (IS) continually motivate various improvements in the state-of-the-art of issues and solutions for advanced geo-information technologies in cloud computing. Reducing IS project risks and improving organizational performance has become an important issue. This study proposes a research framework, constructed from the Stimulus-Organism-Response (S-O-R) framework, in order to address the issues comprising the stimulus of project risk, the organism of project management, and the response of organizational performance for cloud service solutions. Cloud customer relationship management (cloud CRM) experts, based on cloud computing, with many years of project management experience, were selected for the interview sample in this study. Decision Making Trial and Evaluation Laboratory–based analytical network process (DEMATEL based-ANP, DANP) is a multiple-criteria decision-making (MCDM) analysis tool that does not have prior assumptions and it was used to experience the dynamic relationships among project risk, project management, and organizational performance. The study results include three directions: (a) Improving the internal business process performance can improve the efficiency of cloud CRM project processes and activities; (b) The emphasis on financial performance management can reduce the cost of a cloud CRM project so that the project can be completed within the approved budget; (c) Meeting user needs can improve user risk and reduce negative cloud CRM user experience. The scientific value of this study can be extended in order to study different projects, through research methods and frameworks, in order to explore project risk management and corporate performance improvements. Full article
(This article belongs to the Special Issue Advanced Geo-Information Technologies for Anticipatory Computing)
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200 KiB  
Correction
Correction: Yin, J., et al. Exploring Multi-Scale Spatiotemporal Twitter User Mobility Patterns with a Visual-Analytics Approach. ISPRS International Journal of Geo-Information 2016, 5, 187
by Junjun Yin, Yizhao Gao, Zhenhong Du and Shaowen Wang
ISPRS Int. J. Geo-Inf. 2016, 5(12), 226; https://doi.org/10.3390/ijgi5120226 - 1 Dec 2016
Cited by 2 | Viewed by 3469
Abstract
n/a Full article
4238 KiB  
Article
A Biophysical Image Compositing Technique for the Global-Scale Extraction and Mapping of Barren Lands
by Ram C. Sharma, Ryutaro Tateishi and Keitarou Hara
ISPRS Int. J. Geo-Inf. 2016, 5(12), 225; https://doi.org/10.3390/ijgi5120225 - 30 Nov 2016
Cited by 6 | Viewed by 4881
Abstract
As the barren lands play a key role in the interaction between land cover dynamics and climate system, an efficient methodology for the global-scale extraction and mapping of the barren lands is important. The discriminative potential of the existing soil/bareness indexes was assessed [...] Read more.
As the barren lands play a key role in the interaction between land cover dynamics and climate system, an efficient methodology for the global-scale extraction and mapping of the barren lands is important. The discriminative potential of the existing soil/bareness indexes was assessed by collecting globally distributed reference data belonging to major land cover types. The existing soil/bareness indexes parameterized at the local scale did not work satisfactorily everywhere at the global level. A new technique called the Biophysical Image Composite (BIC) is proposed in the research by exploiting time-series of the multi-spectral data to capture global-scale barren land attributes effectively. The BIC is a false color composite image made up of Normalized Difference Vegetation Index (NDVI), short wave infrared reflectance, and green reflectance, which were specially selected from the highest vegetation activity period by avoiding signals from the seasonal snowfall. The drastic contrast between the barren lands and vegetation as exhibited by the BIC provides a robust extraction and mapping of the barren lands, and facilitates its visual interpretation. Random Forests based supervised classification approach was applied on the BIC for the mapping of global barren lands. A new global barren land cover map of year 2013 was produced with high accuracy. The comparison of the resulted map with an existing map of the same year showed a substantial discrepancy between two maps due to methodological variation. To cope with this problem, the BIC based mapping methodology, with a special account of the land surface phenological changes, is suggested to standardize the global-scale estimates and mapping of the barren lands. Full article
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4044 KiB  
Article
An Improved WiFi/PDR Integrated System Using an Adaptive and Robust Filter for Indoor Localization
by Zengke Li, Chunyan Liu, Jingxiang Gao and Xin Li
ISPRS Int. J. Geo-Inf. 2016, 5(12), 224; https://doi.org/10.3390/ijgi5120224 - 30 Nov 2016
Cited by 33 | Viewed by 5781
Abstract
Location-based services (LBS) are services offered through a mobile device that take into account a device’s geographical location. To provide position information for these services, location is a key process. GNSS (Global Navigation Satellite System) can provide sub-meter accuracy in open-sky areas using [...] Read more.
Location-based services (LBS) are services offered through a mobile device that take into account a device’s geographical location. To provide position information for these services, location is a key process. GNSS (Global Navigation Satellite System) can provide sub-meter accuracy in open-sky areas using satellite signals. However, for indoor and dense urban environments, the accuracy deteriorates significantly because of weak signals and dense multipaths. The situation becomes worse in indoor environments where the GNSS signals are unreliable or totally blocked. To improve the accuracy of indoor positioning for location-based services, an improved WiFi/Pedestrian Dead Reckoning (PDR) integrated positioning and navigation system using an adaptive and robust filter is presented. The adaptive filter is based on scenario and motion state recognition and the robust filter is based on the Mahalanobis distance. They are combined and used in the WiFi/PDR integrated system to weaken the effect of gross errors on the dynamic and observation models. To validate their performance in the WiFi/PDR integrated system, a real indoor localization experiment is conducted. The results indicate that the adaptive filter is better able to adapt to the circumstances of the dynamic model by adjusting the covariance of the process noise and the robust Kalman filter is able to mitigate the harmful effect of gross errors from the WiFi positioning. Full article
(This article belongs to the Special Issue Location-Based Services)
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3150 KiB  
Article
A Novel Evaluation Approach for Line Simplification Algorithms towards Vector Map Visualization
by Jia Song and Ru Miao
ISPRS Int. J. Geo-Inf. 2016, 5(12), 223; https://doi.org/10.3390/ijgi5120223 - 29 Nov 2016
Cited by 13 | Viewed by 5843
Abstract
Line simplification is an important method in the context of cartographic generalization, which is helpful for improving the visualization of digital vector maps. The evaluation method for the simplification algorithms is still an open issue when facing applications of vector data, including progressive [...] Read more.
Line simplification is an important method in the context of cartographic generalization, which is helpful for improving the visualization of digital vector maps. The evaluation method for the simplification algorithms is still an open issue when facing applications of vector data, including progressive transmission, web mapping, and so on. This paper proposes a novel evaluation approach for line simplification algorithms based on several factors towards vector map visualization, including the features of displays, map scales, and the ability of the human eye to distinguish pixels. In order to ensure the evaluation of the line simplification algorithms is conducted under the consistent strength of simplification, a measurement approach for the difference between an original line and its simplified one is proposed in this study, and the method of solving the appropriate simplification threshold is presented. With this method, four simplification algorithms are evaluated at five map scales using three evaluation indicators: standard deviation, compression ratio, and simplification time. The experiment and results show the evaluation approach in this study is feasible, and represents a good means in which to facilitate the application of line simplification towards progressive transmission and visualization of vector maps. Full article
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3019 KiB  
Article
Adjustment and Assessment of the Measurements of Low and High Sampling Frequencies of GPS Real-Time Monitoring of Structural Movement
by Mosbeh R. Kaloop, Jong Wan Hu and Emad Elbeltagi
ISPRS Int. J. Geo-Inf. 2016, 5(12), 222; https://doi.org/10.3390/ijgi5120222 - 29 Nov 2016
Cited by 19 | Viewed by 5163
Abstract
Global Positioning System (GPS) structural health monitoring data collection is one of the important systems in structure movement monitoring. However, GPS measurement error and noise limit the application of such systems. Many attempts have been made to adjust GPS measurements and eliminate their [...] Read more.
Global Positioning System (GPS) structural health monitoring data collection is one of the important systems in structure movement monitoring. However, GPS measurement error and noise limit the application of such systems. Many attempts have been made to adjust GPS measurements and eliminate their errors. Comparing common nonlinear methods used in the adjustment of GPS positioning for the monitoring of structures is the main objective of this study. Nonlinear Adaptive-Recursive Least Square (RLS), extended Kalman filter (EKF), and wavelet principal component analysis (WPCA) are presented and applied to improve the quality of GPS time series observations. Two real monitoring observation systems for the Mansoura railway and long-span Yonghe bridges are utilized to examine suitable methods used to assess bridge behavior under different load conditions. From the analysis of the results, it is concluded that the wavelet principal component is the best method to smooth low and high GPS sampling frequency observations. The evaluation of the bridges reveals the ability of the GPS systems to detect the behavior and damage of structures in both the time and frequency domains. Full article
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7656 KiB  
Article
Spatiotemporal Information Extraction from a Historic Expedition Gazetteer
by Mafkereseb Kassahun Bekele, Rolf A. De By and Gaurav Singh
ISPRS Int. J. Geo-Inf. 2016, 5(12), 221; https://doi.org/10.3390/ijgi5120221 - 29 Nov 2016
Cited by 5 | Viewed by 5741
Abstract
Historic expeditions are events that are flavored by exploratory, scientific, military or geographic characteristics. Such events are often documented in literature, journey notes or personal diaries. A typical historic expedition involves multiple site visits and their descriptions contain spatiotemporal and attributive contexts. Expeditions [...] Read more.
Historic expeditions are events that are flavored by exploratory, scientific, military or geographic characteristics. Such events are often documented in literature, journey notes or personal diaries. A typical historic expedition involves multiple site visits and their descriptions contain spatiotemporal and attributive contexts. Expeditions involve movements in space that can be represented by triplet features (location, time and description). However, such features are implicit and innate parts of textual documents. Extracting the geospatial information from these documents requires understanding the contextualized entities in the text. To this end, we developed a semi-automated framework that has multiple Information Retrieval and Natural Language Processing components to extract the spatiotemporal information from a two-volume historic expedition gazetteer. Our framework has three basic components, namely, the Text Preprocessor, the Gazetteer Processing Machine and the JAPE (Java Annotation Pattern Engine) Transducer. We used the Brazilian Ornithological Gazetteer as an experimental dataset and extracted the spatial and temporal entities from entries that refer to three expeditioners’ site visits (which took place between 1910 and 1926) and mapped the trajectory of each expedition using the extracted information. Finally, one of the mapped trajectories was manually compared with a historical reference map of that expedition to assess the reliability of our framework. Full article
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4945 KiB  
Article
Indoor Multi-Dimensional Location GML and Its Application for Ubiquitous Indoor Location Services
by Qing Zhu, Yun Li, Qing Xiong, Sisi Zlatanova, Yulin Ding, Yeting Zhang and Yan Zhou
ISPRS Int. J. Geo-Inf. 2016, 5(12), 220; https://doi.org/10.3390/ijgi5120220 - 29 Nov 2016
Cited by 19 | Viewed by 7883
Abstract
The Open Geospatial Consortium (OGC) Geography Markup Language (GML) standard provides basic types and a framework for defining geo-informational data models such as CityGML and IndoorGML, which provide standard information models for 3D city modelling and lightweight indoor network navigation. Location information, which [...] Read more.
The Open Geospatial Consortium (OGC) Geography Markup Language (GML) standard provides basic types and a framework for defining geo-informational data models such as CityGML and IndoorGML, which provide standard information models for 3D city modelling and lightweight indoor network navigation. Location information, which is the semantic engine that fuses big geo-information data, is however, discarded in these standards. The Chinese national standard of Indoor Multi-Dimensional Location GML (IndoorLocationGML) presented in this study can be used in ubiquitous indoor location intelligent applications for people and robots. IndoorLocationGML is intended as an indoor multi-dimensional location information model and exchange data format standard, mainly for indoor positioning and navigation. This paper introduces the standard’s main features: (1) terminology; (2) indoor location information model using a Unified Modeling Language (UML) class diagram; (3) indoor location information markup language based on GML; and (4) use cases. A typical application of the standard is then discussed. This standard is applicable to the expression, storage, and distribution of indoor multi-dimensional location information, and to the seamless integration of indoor–outdoor location information. The reference and basis are therefore relevant to publishers, managers, users, and developers of indoor navigation and location-based services (LBS). Full article
(This article belongs to the Special Issue 3D Indoor Modelling and Navigation)
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1758 KiB  
Article
Geospatial Analysis of the Building Heat Demand and Distribution Losses in a District Heating Network
by Tobias Törnros, Bernd Resch, Matthias Rupp and Hartmut Gündra
ISPRS Int. J. Geo-Inf. 2016, 5(12), 219; https://doi.org/10.3390/ijgi5120219 - 24 Nov 2016
Cited by 9 | Viewed by 6206
Abstract
The district heating (DH) demand of various systems has been simulated in several studies. Most studies focus on the temporal aspects rather than the spatial component. In this study, the DH demand for a medium-sized DH network in a city in southern Germany [...] Read more.
The district heating (DH) demand of various systems has been simulated in several studies. Most studies focus on the temporal aspects rather than the spatial component. In this study, the DH demand for a medium-sized DH network in a city in southern Germany is simulated and analyzed in a spatially explicit approach. Initially, buildings are geo-located and attributes obtained from various sources including building type, ground area, and number of stories are merged. Thereafter, the annual primary energy demand for heating and domestic hot water is calculated for individual buildings. Subsequently, the energy demand is aggregated on the segment level of an existing DH network and the water flow is routed through the system. The simulation results show that the distribution losses are overall the highest at the end segments (given in percentage terms). However, centrally located pipes with a low throughflow are also simulated to have high losses. The spatial analyses are not only useful when addressing the current demand. Based on a scenario taking into account the refurbishment of buildings and a decentralization of energy production, the future demand was also addressed. Due to lower demand, the distribution losses given in percentage increase under such conditions. Full article
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