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In cartographic generalization, the selection is an often-used method to adjust information density in a map. This paper deals with methods for selecting point features for a specific scale with numerical attributes, such as population, elevation, or visitors. With the Label Grid approach and the method of Functional Importance, two existing approaches are described, which have not been published in the scientific literature so far. They are explained and illustrated in the method chapter for better understanding. Furthermore, a new approach based on the Discrete Isolation measure is introduced. It combines the spatial position and the attribute's value and is defined as the minimum distance to the nearest point with a higher value. All described selection methods are implemented and made available as Plugins named “Point selection algorithms” for QGIS. Based on this implementation, the three methods are compared regarding runtime, parameterization, legibility, and generalization degree. Finally, recommendations are given on which data and use cases the approaches are suitable. We see digital maps with multiple scales as the main application of those methods. The possibilities of labeling the selected points are not considered within the scope of this work.
Mathias Gröbe; Dirk Burghardt. Scale-Dependent Point Selection Methods for Web Maps. KN - Journal of Cartography and Geographic Information 2021, 1 -12.
AMA StyleMathias Gröbe, Dirk Burghardt. Scale-Dependent Point Selection Methods for Web Maps. KN - Journal of Cartography and Geographic Information. 2021; ():1-12.
Chicago/Turabian StyleMathias Gröbe; Dirk Burghardt. 2021. "Scale-Dependent Point Selection Methods for Web Maps." KN - Journal of Cartography and Geographic Information , no. : 1-12.
Map generalization is a process of hierarchically reorganizing features whereby the global shape of the original datasets can be transferred in different scales. We propose a stroke and centrality-based method to hierarchically extract the skeleton structures from buildings aiming to support generalization. Firstly, the strokes are generated from refined proximity graph network. Next, by regarding the strokes as dual graph, three centrality indices are calculated for each stroke whereby an integrated factor is created to measure the importance level of the strokes. Finally, the hierarchical skeleton structures are extracted based on the stroke importance levels through different selection ratios. By classifying the buildings into different categories, different generalization operators are selected considering their characteristics. The experimental results demonstrate that the extracted hierarchical skeleton structures can represent the global shape of the entire region. Through this support, the global and local patterns of the original buildings can be both preserved.
Xiao Wang; Dirk Burghardt. Hierarchical Extraction of Skeleton Structures from Discrete Buildings. The Cartographic Journal 2021, 1 -22.
AMA StyleXiao Wang, Dirk Burghardt. Hierarchical Extraction of Skeleton Structures from Discrete Buildings. The Cartographic Journal. 2021; ():1-22.
Chicago/Turabian StyleXiao Wang; Dirk Burghardt. 2021. "Hierarchical Extraction of Skeleton Structures from Discrete Buildings." The Cartographic Journal , no. : 1-22.
The presented study aims to investigate the relationship between the use of emojis in location-based social media and the location of the corresponding post in terms of perceived objects and conducted activities connected to this place. The basis for this is not a purely frequency-based assessment, but a specifically introduced measure called typicality. To evaluate the typicality measure and examine the assumption that emojis are contextual indicants, a dataset of worldwide geotagged posts from Instagram relating to sunset and sunrise events is used, converted to a privacy-aware version based on a Hyperloglog approach. Results suggest that emojis can often provide more nuanced information about user activities and the surrounding environment than is possible with hashtags. Thus, emojis may be suitable for identifying less obvious characteristics and the sense of a place. Emojis are already explored in research, but mainly for sentiment analysis, for semantic studies or as part of emoji prediction. In contrast, this work provides novel insights into the user’s spatial or activity context by applying the typicality measure and therefore considers emojis contextual indicants.
Eva Hauthal; Alexander Dunkel; Dirk Burghardt. Emojis as Contextual Indicants in Location-Based Social Media Posts. ISPRS International Journal of Geo-Information 2021, 10, 407 .
AMA StyleEva Hauthal, Alexander Dunkel, Dirk Burghardt. Emojis as Contextual Indicants in Location-Based Social Media Posts. ISPRS International Journal of Geo-Information. 2021; 10 (6):407.
Chicago/Turabian StyleEva Hauthal; Alexander Dunkel; Dirk Burghardt. 2021. "Emojis as Contextual Indicants in Location-Based Social Media Posts." ISPRS International Journal of Geo-Information 10, no. 6: 407.
Urban Growth Boundary (UGB) is a growth management policy that designates specific areas where growth should be concentrated in order to avoid urban sprawl. The objective of such a boundary is to protect agricultural land, open spaces and the natural environment, as well as to use existing infrastructure and public services more efficiently. Due to the inherent heterogeneity and complexity of settlements, UGBs in Germany are currently created manually by experts. Therefore, every dataset is linked to a specific area, investigation period and dedicated use. Clearly, up-to-date, homogeneous, meaningful and cost-efficient delineations created automatically are needed to avoid this reliance on manually or semi-automatically generated delineations. Here, we present an aggregative method to produce UGBs using building footprints and generally available topographic data as inputs. It was applied to study areas in Frankfurt/Main, the Hanover region and rural Brandenburg while taking full account of Germany’s planning and legal framework for spatial development. Our method is able to compensate for most of the weaknesses of available UGB data and to significantly raise the accuracy of UGBs in Germany. Therefore, it represents a valuable tool for generating basic data for future studies. Application elsewhere is also conceivable by regionalising the employed parameters.
Oliver Harig; Robert Hecht; Dirk Burghardt; Gotthard Meinel. Automatic Delineation of Urban Growth Boundaries Based on Topographic Data Using Germany as a Case Study. ISPRS International Journal of Geo-Information 2021, 10, 353 .
AMA StyleOliver Harig, Robert Hecht, Dirk Burghardt, Gotthard Meinel. Automatic Delineation of Urban Growth Boundaries Based on Topographic Data Using Germany as a Case Study. ISPRS International Journal of Geo-Information. 2021; 10 (5):353.
Chicago/Turabian StyleOliver Harig; Robert Hecht; Dirk Burghardt; Gotthard Meinel. 2021. "Automatic Delineation of Urban Growth Boundaries Based on Topographic Data Using Germany as a Case Study." ISPRS International Journal of Geo-Information 10, no. 5: 353.
Social media data is heavily used to analyze and evaluate situations in times of disasters, and derive decisions for action from it. In these critical situations, it is not surprising that privacy is often considered a secondary problem. In order to prevent subsequent abuse, theft or public exposure of collected datasets, however, protecting the privacy of social media users is crucial. Avoiding unnecessary data retention is an important question that is currently largely unsolved. There are a number of technical approaches available, but their deployment in disaster management is either impractical or requires special adaption, limiting its utility. In this case study, we explore the deployment of a cardinality estimation algorithm called HyperLogLog into disaster management processes. It is particularly suited for this field, because it allows to stream data in a format that cannot be used for purposes other than the originally intended. We develop and conduct a focus group discussion with teams of social media analysts. We identify challenges and opportunities of working with such a privacy-enhanced social media data format and compare the process with conventional techniques. Our findings show that, with the exception of training scenarios, deploying HyperLogLog in the data acquisition process will not distract the data analysis process. Instead, several benefits, such as improved working with huge datasets, may contribute to a more widespread use and adoption of the presented technique, which provides a basis for a better integration of privacy considerations in disaster management.
Marc Löchner; Ramian Fathi; David Schmid; Alexander Dunkel; Dirk Burghardt; Frank Fiedrich; Steffen Koch. Case Study on Privacy-aware Social Media Data Processing in Disaster Management. ISPRS International Journal of Geo-Information 2020, 9, 709 .
AMA StyleMarc Löchner, Ramian Fathi, David Schmid, Alexander Dunkel, Dirk Burghardt, Frank Fiedrich, Steffen Koch. Case Study on Privacy-aware Social Media Data Processing in Disaster Management. ISPRS International Journal of Geo-Information. 2020; 9 (12):709.
Chicago/Turabian StyleMarc Löchner; Ramian Fathi; David Schmid; Alexander Dunkel; Dirk Burghardt; Frank Fiedrich; Steffen Koch. 2020. "Case Study on Privacy-aware Social Media Data Processing in Disaster Management." ISPRS International Journal of Geo-Information 9, no. 12: 709.
Through volunteering data, people can help assess information on various aspects of their surrounding environment. Particularly in natural resource management, Volunteered Geographic Information (VGI) is increasingly recognized as a significant resource, for example, supporting visitation pattern analysis to evaluate collective values and improve natural well-being. In recent years, however, user privacy has become an increasingly important consideration. Potential conflicts often emerge from the fact that VGI can be re-used in contexts not originally considered by volunteers. Addressing these privacy conflicts is particularly problematic in natural resource management, where visualizations are often explorative, with multifaceted and sometimes initially unknown sets of analysis outcomes. In this paper, we present an integrated and component-based approach to privacy-aware visualization of VGI, specifically suited for application to natural resource management. As a key component, HyperLogLog (HLL)—a data abstraction format—is used to allow estimation of results, instead of more accurate measurements. While HLL alone cannot preserve privacy, it can be combined with existing approaches to improve privacy while, at the same time, maintaining some flexibility of analysis. Together, these components make it possible to gradually reduce privacy risks for volunteers at various steps of the analytical process. A specific use case demonstration is provided, based on a global, publicly-available dataset that contains 100 million photos shared by 581,099 users under Creative Commons licenses. Both the data processing pipeline and resulting dataset are made available, allowing transparent benchmarking of the privacy–utility tradeoffs.
Alexander Dunkel; Marc Löchner; Dirk Burghardt. Privacy-Aware Visualization of Volunteered Geographic Information (VGI) to Analyze Spatial Activity: A Benchmark Implementation. ISPRS International Journal of Geo-Information 2020, 9, 607 .
AMA StyleAlexander Dunkel, Marc Löchner, Dirk Burghardt. Privacy-Aware Visualization of Volunteered Geographic Information (VGI) to Analyze Spatial Activity: A Benchmark Implementation. ISPRS International Journal of Geo-Information. 2020; 9 (10):607.
Chicago/Turabian StyleAlexander Dunkel; Marc Löchner; Dirk Burghardt. 2020. "Privacy-Aware Visualization of Volunteered Geographic Information (VGI) to Analyze Spatial Activity: A Benchmark Implementation." ISPRS International Journal of Geo-Information 9, no. 10: 607.
Location-based social media data from different platforms such as Twitter and Flickr increasingly serve with their point-geocoded content as data sources for a variety of applications. The standard visualization method uses a derivation of point maps, which works well with a limited amount of data, but it suffers from weaknesses related to cluttering and overlapping, especially for sets of categories. We developed a new visualization method for categorical point data, called “Micro Diagrams”, which uses small diagrams to show the percentages of categories and the spatial distribution. The processing steps to derive the micro diagrams start with aggregating the points in a regular grid structure, which is followed by the selection of the diagram type that represents the numerical proportions and the application of a size scaling function to show the amounts of data. Various parameterization options are discussed and the influence of the color selection is analyzed. Finally, a case study combined with a user test presents the strengths and limits of the micro diagram method.
Mathias Gröbe; Dirk Burghardt. Micro diagrams: visualization of categorical point data from location-based social media. Cartography and Geographic Information Science 2020, 47, 305 -320.
AMA StyleMathias Gröbe, Dirk Burghardt. Micro diagrams: visualization of categorical point data from location-based social media. Cartography and Geographic Information Science. 2020; 47 (4):305-320.
Chicago/Turabian StyleMathias Gröbe; Dirk Burghardt. 2020. "Micro diagrams: visualization of categorical point data from location-based social media." Cartography and Geographic Information Science 47, no. 4: 305-320.
Linear building groups are common patterns and important local structures in large scale maps, which should be carefully generalized. This paper uses the idea of line simplification to typify linear building groups. Firstly, based on the stroke idea, the linear building groups are detected that each building group is related by only one stroke; the collinear and curvilinear patterns are distinguished by calculating the overlap rate between the defined auxiliary polygon and its oriented bounding box. Secondly, the stroke is simplified by removing one node in each iterative step; and the remained nodes are reallocated to the new positions, which serves as the centroids location of the newly typified buildings. Third, the representation (size, shape, elongation, and orientation) of the newly typified buildings are calculated by the geometry information of their corresponding parent buildings. The typification method can be carried out as a progressive process, which iterates over the three steps to derive continuous typification results. The method is tested on two building datasets, and the experimental results demonstrate that the proposed method can achieve good performance by well preserving the original linear patterns in the generalized building groups.
Xiao Wang; Dirk Burghardt. A typification method for linear building groups based on stroke simplification. Geocarto International 2019, 36, 1732 -1751.
AMA StyleXiao Wang, Dirk Burghardt. A typification method for linear building groups based on stroke simplification. Geocarto International. 2019; 36 (15):1732-1751.
Chicago/Turabian StyleXiao Wang; Dirk Burghardt. 2019. "A typification method for linear building groups based on stroke simplification." Geocarto International 36, no. 15: 1732-1751.
Building patterns are crucial structures and should be preserved in map generalization. However, while building patterns are not explicitly described in building datasets, map readers perceive building patterns effortlessly. Hence, to better support map generalization, it is important to automatically recognize building patterns in such datasets. This paper first proposes an extended and integrated typology of different building patterns. Based on the typology, building patterns are recognized using stroke and mesh. This method first structures the proximity graph of buildings, and then introduces six constraints (distance, size, shape, orientation, elongation, and facing ratio) to refine the original proximity graph. Strokes and meshes are derived from the refined proximity graph, and are used to recognize linear and grid building patterns, respectively. The proposed method is tested in four regions that are representative of different pattern types. The recognition results are evaluated in an expert survey and compared with the minimum spanning tree method. Assessment suggests that the linear and grid patterns in suburban and rural areas are recognized with satisfying results.
Xiao Wang; Dirk Burghardt. Using stroke and mesh to recognize building group patterns. International Journal of Cartography 2019, 6, 71 -98.
AMA StyleXiao Wang, Dirk Burghardt. Using stroke and mesh to recognize building group patterns. International Journal of Cartography. 2019; 6 (1):71-98.
Chicago/Turabian StyleXiao Wang; Dirk Burghardt. 2019. "Using stroke and mesh to recognize building group patterns." International Journal of Cartography 6, no. 1: 71-98.
Building groups with special patterns are common layouts in urban settlement areas, which should be carefully generalized. Typification is considered as an appropriate operator to generalize building groups with grid patterns. As an important operator in building generalization, the purpose of typification is to reduce the number of objects while preserving the original distribution characteristics as much as possible. This study proposes a mesh-based method to typify buildings with grid patterns. Firstly, the pattern is subdivided into perfect grid or grid-like patterns by considering the completeness of the grids. The proposed typification method consists of three steps: (1) generating mesh from the proximity graph of buildings; (2) eliminating triangular meshes; (3) determining the number, positions, and representations of the newly created buildings with the help of the related meshes. The proposed method is modeled as an iterative process to achieve hierarchical typification results, which provides support to the map multiple representation. The experimental results demonstrate that the mesh-based typification method can achieve satisfying results in the perfect grid pattern, as well as the grid-like pattern. The new distribution of the typified buildings preserves the original pattern characteristics.
Xiao Wang; Dirk Burghardt. A Mesh-Based Typification Method for Building Groups with Grid Patterns. ISPRS International Journal of Geo-Information 2019, 8, 168 .
AMA StyleXiao Wang, Dirk Burghardt. A Mesh-Based Typification Method for Building Groups with Grid Patterns. ISPRS International Journal of Geo-Information. 2019; 8 (4):168.
Chicago/Turabian StyleXiao Wang; Dirk Burghardt. 2019. "A Mesh-Based Typification Method for Building Groups with Grid Patterns." ISPRS International Journal of Geo-Information 8, no. 4: 168.
We live in an age in which digital media is omnipresent and augmented reality is beginning to find its way into our everyday lives, GPS allows us to determine our position with meter precision and the sensor capabilities of smartphones are increasing. All these technologies in combination enable us to explore one of the oldest human art forms in a new way: storytelling. The presented work aims at developing approaches that combine different elements of audio media playback, geolocation and other sensor capabilities of smartphones to allow the creation of immersive geolocated narratives within a mobile application. Thus, the narrative can be precisely adjusted to the specific spatial and temporal context of the user. One of the main goals of such a geolocated narrative would be to influence the cognitive processing of the users. As the visual perception of the location stays the same while using the app, it is only the auditory cognition that causes a subtle enhancement and thus alteration of the reality which could result in a very strong sense of immersion. There are many location-based audio applications on the market. Most of them are intended for tourism in the form of an audio tour guide. Some of those applications have been analyzed before developing our own ideas on how to intertwine sound, space and time into an immersive mobile application for storytelling with semi-linear narrative structures including a map. Possible features could be influenceability of the narrative by, e.g., speed or approach direction of the user, sound movement over time on predetermined routes, etc. The first prototype implemented some audiovisual presentations among others. Wir leben in einem Zeitalter, in welchem digitale Medien omnipräsent sind und Augmented Reality Einzug ins tägliche Leben erhält, in dem GPS uns befähigt, unsere Position mit Meter-Genauigkeit zu bestimmen und sich das Sensor-Potential von Smartphones erhöht. Das Zusammenspiel all dieser Technologien erlaubt es, eine der ältesten Kunstformen neu zu entdecken: die Erzählkunst. Die vorliegende Arbeit hat zum Ziel, Ansätze zu entwickeln, welche verschiedene Elemente der Audio-Wiedergabe, Geolokalisierung und andere Sensor-Fähigkeiten kombinieren, um immersive, räumlich verortete Narrative für eine mobile Anwendung zu kreieren. Damit können Geschichten präzise an den spezifischen räumlich-zeitlichen Kontext des Nutzers angepasst werden. Die Hauptabsicht einer solchen ortbezogenen Geschichte ist es, die kognitive Wahrnehmung des Nutzers zu beeinflussen. Da während der App-Nutzung die visuelle Wahrnehmung der Umgebung gleich bleibt, ist es nur die auditive Wahrnehmung, welche eine subtile Anreicherung und damit eine Veränderung der Realität bewirkt, was ein starkes immersives Erleben hervorrufen kann. Es sind zahlreiche ortbasierte Audio-Anwendungen auf dem Markt. Bei den meisten handelt es sich um touristische Audio-Führer. Einige dieser Anwendungen wurden untersucht, bevor eigene Konzepte entwickelt wurden, wie die Verflechtung von Klang, Raum und Zeit zu einer immersiven Audio-Anwendung (inklusive einer Karte) für Storytelling mit semi-linearen narrativen Strukturen umgesetzt werden kann. Mögliche Funktionen hierbei wären beispielsweise die Beeinflussbarkeit der Geschichte durch Geschwindigkeit oder Bewegungsrichtung des Nutzers oder Bewegung von Klängen auf vordefinierten Routen. In einem ersten Prototypen wurden unter anderem einige audio-visuelle Präsentationen implementiert.
Reinis Indans; Eva Hauthal; Dirk Burghardt. Towards an Audio-Locative Mobile Application for Immersive Storytelling. KN - Journal of Cartography and Geographic Information 2019, 69, 41 -50.
AMA StyleReinis Indans, Eva Hauthal, Dirk Burghardt. Towards an Audio-Locative Mobile Application for Immersive Storytelling. KN - Journal of Cartography and Geographic Information. 2019; 69 (1):41-50.
Chicago/Turabian StyleReinis Indans; Eva Hauthal; Dirk Burghardt. 2019. "Towards an Audio-Locative Mobile Application for Immersive Storytelling." KN - Journal of Cartography and Geographic Information 69, no. 1: 41-50.
Social media platforms such as Twitter are extensively used for expressing and exchanging thoughts, opinions, ideas, and feelings, i.e., reactions concerning a topic or an event. Factual information about an event to which people are reacting can be obtained from different types of (geo-)sensors, official authorities, or the public press. However, these sources hardly reveal the emotional or attitudinal impact of events on people, which is, for example, reflected in their reactions on social media. Two approaches that utilize emojis are proposed to obtain the sentiment and emotions contained in social media reactions. Subsequently, these two approaches, along with visualizations that focus on space, time, and topic, are applied to Twitter reactions in the example case of Brexit.
Eva Hauthal; Dirk Burghardt; Alexander Dunkel. Analyzing and Visualizing Emotional Reactions Expressed by Emojis in Location-Based Social Media. ISPRS International Journal of Geo-Information 2019, 8, 113 .
AMA StyleEva Hauthal, Dirk Burghardt, Alexander Dunkel. Analyzing and Visualizing Emotional Reactions Expressed by Emojis in Location-Based Social Media. ISPRS International Journal of Geo-Information. 2019; 8 (3):113.
Chicago/Turabian StyleEva Hauthal; Dirk Burghardt; Alexander Dunkel. 2019. "Analyzing and Visualizing Emotional Reactions Expressed by Emojis in Location-Based Social Media." ISPRS International Journal of Geo-Information 8, no. 3: 113.
Events are a core concept of spatial information, but location-based social media (LBSM) provide information on reactions to events. Individuals have varied degrees of agency in initiating, reacting to or modifying the course of events, and reactions include observations of occurrence, expressions containing sentiment or emotions, or a call to action. Key characteristics of reactions include referent events and information about who reacted, when, where and how. Collective reactions are composed of multiple individual reactions sharing common referents. They can be characterized according to the following dimensions: spatial, temporal, social, thematic and interlinkage. We present a conceptual framework, which allows characterization and comparison of collective reactions. For a thematically well-defined class of event such as storms, we can explore differences and similarities in collective attribution of meaning across space and time. Other events may have very complex spatio-temporal signatures (e.g. political processes such as Brexit or elections), which can be decomposed into series of individual events (e.g. a temporal window around the result of a vote). The purpose of our framework is to explore ways in which collective reactions to events in LBSM can be described and underpin the development of methods for analysing and understanding collective reactions to events.
Alexander Dunkel; Gennady Andrienko; Natalia Andrienko; Dirk Burghardt; Eva Hauthal; Ross Purves. A conceptual framework for studying collective reactions to events in location-based social media. International Journal of Geographical Information Science 2018, 33, 780 -804.
AMA StyleAlexander Dunkel, Gennady Andrienko, Natalia Andrienko, Dirk Burghardt, Eva Hauthal, Ross Purves. A conceptual framework for studying collective reactions to events in location-based social media. International Journal of Geographical Information Science. 2018; 33 (4):780-804.
Chicago/Turabian StyleAlexander Dunkel; Gennady Andrienko; Natalia Andrienko; Dirk Burghardt; Eva Hauthal; Ross Purves. 2018. "A conceptual framework for studying collective reactions to events in location-based social media." International Journal of Geographical Information Science 33, no. 4: 780-804.
In the past years Volunteered Geographic Information (VGI) has emerged as a novel form of user-generated content, which involves active generation of geo-data for example in citizen science projects or during crisis mapping as well as the passive collection of data via the user’s location-enabled mobile devices. In addition there are more and more sensors available that detect our environment with ever greater detail and dynamics. These data can be used for a variety of applications, not only for the solution of societal tasks such as in environment, health or transport fields, but also for the development of commercial products and services. The interpretation, visualisation and usage of such multi-source data is challenging because of the large heterogeneity, the differences in quality, the high update frequencies, the varying spatial-temporal resolution, subjective characteristics and low semantic structuring. Therefore the German Research Foundation has launched a priority programme for the next 3–6 years which will support interdisciplinary research projects. This priority programme aims to provide a scientific basis for raising the potential of VGI- and sensor data. Research questions described more in detail in this short paper span from the extraction of spatial information, to the visual analysis and knowledge presentation, taking into account the social context while collecting and using VGI.
Dirk Burghardt; Wolfgang Nejdl; Jochen Schiewe; Monika Sester. Volunteered Geographic Information: Interpretation, Visualisation and Social Computing (VGIscience). Proceedings of the ICA 2018, 1, 1 -5.
AMA StyleDirk Burghardt, Wolfgang Nejdl, Jochen Schiewe, Monika Sester. Volunteered Geographic Information: Interpretation, Visualisation and Social Computing (VGIscience). Proceedings of the ICA. 2018; 1 ():1-5.
Chicago/Turabian StyleDirk Burghardt; Wolfgang Nejdl; Jochen Schiewe; Monika Sester. 2018. "Volunteered Geographic Information: Interpretation, Visualisation and Social Computing (VGIscience)." Proceedings of the ICA 1, no. : 1-5.
User-generated content is a valuable source of information whose production increases year after year. Twitter data is a form of user-generated content that is frequently adopted to comment on life activities in several contexts. Thus, scientific interest in that data has increased in recent years. This paper focusses on visual analytics approaches addressing the microblogging content exchanged through Twitter. In particular, we concentrate our interest on approaches that consider spatial and temporal aspects and provide visual support. Articles from the major conferences, journals, and digital libraries have been collected, organized and compared based on different criteria such as research questions, application focus, analytical and visual methods adopted, and interaction provided. In addition to these comparisons, opportunities and challenges are illustrated to inspire future research.
Alessio Bertone; Dirk Burghardt. A Survey on Visual Analytics for the Spatio-Temporal Exploration of Microblogging Content. Journal of Geovisualization and Spatial Analysis 2017, 1, 1 .
AMA StyleAlessio Bertone, Dirk Burghardt. A Survey on Visual Analytics for the Spatio-Temporal Exploration of Microblogging Content. Journal of Geovisualization and Spatial Analysis. 2017; 1 (1):1.
Chicago/Turabian StyleAlessio Bertone; Dirk Burghardt. 2017. "A Survey on Visual Analytics for the Spatio-Temporal Exploration of Microblogging Content." Journal of Geovisualization and Spatial Analysis 1, no. 1: 1.
Map generalization is concerned with the optimal display of geographic information in map form. It involves the careful selection of data and the use of a range of ion techniques that seek to give emphasis to what is important, while still including sufficient contextualizing information. If geographic phenomena are stored at fine levels of detail, the goal of automated map generalization is to derive maps at coarser (smaller) scales. Traditionally, the focus has been on paper maps, but increasingly map generalization services are available via the web, and accessible to users with relatively little cartographic knowledge who wish to integrate data from multiple sources (including their own). These high levels of automation require us to make explicit the relationships and behaviors among geographic phenomena, in order that we can reason about the complex decision-making process that is cartographic design.Keywords:cartography;computational methods;geovisualization;GIS;map generalization;national mapping agencies;scale;spatial analysis;spatial modeling
William A. Mackaness; Dirk Burghardt; Cécile Duchêne. Map Generalization. International Encyclopedia of Geography 2017, 1 -16.
AMA StyleWilliam A. Mackaness, Dirk Burghardt, Cécile Duchêne. Map Generalization. International Encyclopedia of Geography. 2017; ():1-16.
Chicago/Turabian StyleWilliam A. Mackaness; Dirk Burghardt; Cécile Duchêne. 2017. "Map Generalization." International Encyclopedia of Geography , no. : 1-16.
Soziale Medien wie Twitter und Flickr sind zurzeit beliebte Kommunikationsplattformen, die es Nutzern ermöglichen, Kurznachrichten, Fotos oder Links auszutauschen. Inhalte, die für jedermann sichtbar sind, können über Programmierschnittstellen abgerufen, analysiert und weiterverarbeitet werden. Von besonderem Interesse für die Geowissen-schaftler sind Beiträge, deren Metadaten einen Ortsbezug aufweisen. In diesem Artikel wird ein Verfahrensablauf vorgestellt, wie sich aus georeferenziertem Text raumbezogene thematische Informationen unter anderem mittels Text Mining gewinnen und kartographisch darstellen lassen. Visualisierungswerkzeuge können dabei sowohl für semiautomatische Datenaufbereitung als auch für Analyse und Präsentation der extrahierten Informationen verwendet werden. Anhand verschiedener Beispiele wird im Beitrag illustriert, welche Art von Information sich aus den raumbezogenen Daten extrahieren lässt und welche spezifischen Eigenschaften die durch das Kurznachrichtenportal Twitter und die Fotodatenbank Flickr generierten Daten besitzen.
Mathias Gröb; Dirk Burghardt. Geovisualisierung und Text Mining mit Microblogging Content. KN - Journal of Cartography and Geographic Information 2016, 66, 248 -255.
AMA StyleMathias Gröb, Dirk Burghardt. Geovisualisierung und Text Mining mit Microblogging Content. KN - Journal of Cartography and Geographic Information. 2016; 66 (5):248-255.
Chicago/Turabian StyleMathias Gröb; Dirk Burghardt. 2016. "Geovisualisierung und Text Mining mit Microblogging Content." KN - Journal of Cartography and Geographic Information 66, no. 5: 248-255.
Monitoring urban growth and measuring urban sprawl is essential for improving urban planning and development. In this paper, we introduce a supervised approach for the delineation of urban areas using commonly available topographic data and commercial GIS software. The method uses a supervised parameter optimization approach along with buffer-based quality measuring method. The approach was developed, tested and evaluated in terms of possible usage in monitoring built-up areas in spatial science at a very fine-grained level. Results show that built-up area boundaries can be delineated automatically with higher quality compared to the settlement boundaries actually used. The approach has been applied to 166 settlement bodies in Germany. The study shows a very efficient way of extracting settlement boundaries from topographic data and maps and contributes to the quantification and monitoring of urban sprawl. Moreover, the findings from this study can potentially guide policy makers and urban planners from other countries.
Oliver Harig; Dirk Burghardt; Robert Hecht. A Supervised Approach to Delineate Built-Up Areas for Monitoring and Analysis of Settlements. ISPRS International Journal of Geo-Information 2016, 5, 137 .
AMA StyleOliver Harig, Dirk Burghardt, Robert Hecht. A Supervised Approach to Delineate Built-Up Areas for Monitoring and Analysis of Settlements. ISPRS International Journal of Geo-Information. 2016; 5 (8):137.
Chicago/Turabian StyleOliver Harig; Dirk Burghardt; Robert Hecht. 2016. "A Supervised Approach to Delineate Built-Up Areas for Monitoring and Analysis of Settlements." ISPRS International Journal of Geo-Information 5, no. 8: 137.
To comprehensively study and better understand urban dynamic processes — such as densification, growth and sprawl, or shrinkage — spatio-temporal databases that allow to track changes of geographic objects like buildings and urban blocks are essential. While comprehensive databases exist for contemporary data, they usually lack a historic dimension. The manual constitution of historic geographic data, be it based on historic maps or aerial images, is a time consuming and laborious process, however. Therefore, we present an approach to semi-automatically extract this data from binary topographic maps with regard to built-up areas at urban block level. The suitability of topographic maps for historic urban analysis has been proven in previous research. To overcome the challenges that are inherent in scanned topographic maps in regard to digital image interpretation we designed a modular process. Among others, these challenges include fused and (multi-)fragmented map objects caused by the overlap of competing content layers in one single binary map. After a preliminary separation of individual map object layers from the map content, the process follows a two-stage top-down approach. At first, the map is organized into street blocks, which after that are re-delineated in regard to built-up area. In doing so, we achieve correctness values ranging from 0.97 to 0.93 for three study sites in Germany. With an increasing number of projects that provide historic topographic maps as georeferenced digital data, our process represents a promising approach to efficiently prepare these historic data for integration into a spatio-temporal database with minimal user intervention.
Sebastian Muhs; Hendrik Herold; Gotthard Meinel; Dirk Burghardt; Odette Kretschmer. Automatic delineation of built-up area at urban block level from topographic maps. Computers, Environment and Urban Systems 2016, 58, 71 -84.
AMA StyleSebastian Muhs, Hendrik Herold, Gotthard Meinel, Dirk Burghardt, Odette Kretschmer. Automatic delineation of built-up area at urban block level from topographic maps. Computers, Environment and Urban Systems. 2016; 58 ():71-84.
Chicago/Turabian StyleSebastian Muhs; Hendrik Herold; Gotthard Meinel; Dirk Burghardt; Odette Kretschmer. 2016. "Automatic delineation of built-up area at urban block level from topographic maps." Computers, Environment and Urban Systems 58, no. : 71-84.
Producing maps and geo-data at different scales is traditionally one of the main tasks of National (and regional) Mapping Agencies (NMAs). The derivation of low-scale maps (i.e. with less detail) from large-scale maps (with more detail), i.e. generalisation, used to be a manual task of cartographers. With the need for more up-to-date data as well as the development of automated generalisation solutions in both research and industry, NMAs are implementing automated generalisation production lines. To exchange experiences and identify remaining issues, a workshop was organised end 2015 by the Commission on Generalisation and Multirepresentation of the International Cartographic Association and the Commission on Modelling and Processing of the European Spatial Data Research. This paper reports about the workshop outcomes. It shows that, most NMAs have implemented a certain form of automation in their workflows, varying from generalisation of certain features while still maintaining a manual workflow; semiautomated editing and generalisation to a fully automated procedure.
Jantien Stoter; Vincent van Altena; Marc Post; Dirk Burghardt; Cecile Duchêne. AUTOMATED GENERALISATION WITHIN NMAs IN 2016. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences 2016, XLI-B4, 647 -652.
AMA StyleJantien Stoter, Vincent van Altena, Marc Post, Dirk Burghardt, Cecile Duchêne. AUTOMATED GENERALISATION WITHIN NMAs IN 2016. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. 2016; XLI-B4 ():647-652.
Chicago/Turabian StyleJantien Stoter; Vincent van Altena; Marc Post; Dirk Burghardt; Cecile Duchêne. 2016. "AUTOMATED GENERALISATION WITHIN NMAs IN 2016." The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLI-B4, no. : 647-652.