bluuebunny/crossref_metadata_2025 huggingface dataset:
BUILDING FAÇADE SEPARATION IN VERTICAL AERIAL IMAGES
Authors: Meixner P. , Wendel A. , Bischof H. , Leberl F.
Published: October 2012

Abstract. Three-dimensional models of urban environments have great appeal and offer promises of interesting applications. While initially it was of interest to just have such 3D data, it increasingly becomes evident that one really would like to have interpreted urban objects. To be able to interpret buildings we have to split a visible whole building block into its different single buildings. Usually this is done using cadastral information to divide the single land parcels. The problem in this case is that sometimes the building boundaries derived from the cadastre are insufficiently accurate due to several reasons like old databases with lower accuracies or inaccuracies due to transformation between two coordinate systems. For this reason it can happen that a cadastral boundary coming from an old map is displaced by up to several meters and therefore divides two buildings incorrectly. To overcome such problems we incorporate the information from vertical aerial images. We introduce a façade separation method that is able to find individual building façades using multi view stereo. The purpose is to identify the individual façades and separate them from one another before on proceeds with the analysis of a façade's details. The source was a set of overlapping, thus "redundant" vertical aerial images taken by an UltraCam digital aerial camera. Therefore in a first step we determine the building block outlines using the building classification and use the height values from the Digital Surface Model (DSM) to determine approximate "façade quadrilaterals". We also incorporate height discontinuities using the height profiles along the building outlines to enhance our façade separation. In a next step we detect repeated pattern in these "façade images" and use them to separate the façades respectively building blocks from one another. We show that this method can be successfully used to separate building façades using vertical aerial images with a very high detection rate of 88%.
CONDITIONAL RANDOM FIELDS FOR LIDAR POINT CLOUD CLASSIFICATION IN COMPLEX URBAN AREAS
Authors: Niemeyer J. , Rottensteiner F. , Soergel U.
Published: October 2012

Abstract. In this paper, we investigate the potential of a Conditional Random Field (CRF) approach for the classification of an airborne LiDAR (Light Detection And Ranging) point cloud. This method enables the incorporation of contextual information and learning of specific relations of object classes within a training step. Thus, it is a powerful approach for obtaining reliable results even in complex urban scenes. Geometrical features as well as an intensity value are used to distinguish the five object classes building, low vegetation, tree, natural ground, and asphalt ground. The performance of our method is evaluated on the dataset of Vaihingen, Germany, in the context of the 'ISPRS Test Project on Urban Classification and 3D Building Reconstruction'. Therefore, the results of the 3D classification were submitted as a 2D binary label image for a subset of two classes, namely building and tree.
DIAGNOSTIC-ROBUST STATISTICAL ANALYSIS FOR LOCAL SURFACE FITTING IN 3D POINT CLOUD DATA
Authors: Nurunnabi A. , Belton D. , West G.
Published: October 2012

Abstract. This paper investigates the problem of local surface reconstruction and best fitting for planar surfaces from unorganized 3D point cloud data. Least Squares (LS), its equivalent Principal Component Analysis (PCA) and RANSAC are the three most popular techniques for fitting planar surfaces to 3D data. LS and PCA are sensitive to outliers and do not give reliable and robust parameter estimation. The RANSAC algorithm is robust but it is not completely free from the effect of outliers and is slow for large datasets. In this paper, we propose a diagnostic-robust statistical algorithm that uses both diagnostics and robust approaches in combination for fitting planar surfaces in the presence of outliers. Recently introduced high breakdown and fast Minimum Covariance Determinant (MCD) based location and scatter estimates are used for robust distance to identify outliers and a MCD based robust PCA approach is used as an outlier resistant technique for plane fitting. The benefits of the new diagnostic-robust algorithm are demonstrated with artificial and real laser scanning point cloud datasets. Results show that the proposed method is significantly better and more efficient than the other three methods for planar surface fitting. This method also has great potential for robust local normal estimation and for other surface shape fitting applications.
COMPARISON OF LASER SCANNING, PHOTOGRAMMETRY AND SFM-MVS PIPELINE APPLIED IN STRUCTURES AND ARTIFICIAL SURFACES
Authors: Skarlatos D. , Kiparissi S.
Published: October 2012

Abstract. The merging of photogrammetry and computer vision has raised discussions regarding its ability to produce very dense point clouds, comparable, under circumstances to terrestrial laser scanning (TLS). This paper approaches this issue in terms of accuracy, density, methodology and ease to use. Three tests have been conducted to evaluate the process as well as data density, quality, registration and methodology. At the first test a 300 mm sphere with texture has been used as a reference object is order to address data quality using image based techniques. Menci's Zscan was tested against the Bundler-PMVS work flow. The second test is a flat building facade, where Zscan, TLS and Bundler-PMVS are compared directly. The last test was contacted in an electricity power station which was an extremely complex structure. Two TLS stations were compared against 212 Bundler-PMVS photos. Quantitative comparisons based on several criteria are presented. For small and medium size objects and distances Bundler-PMVS seems to have an advantage in terms of methodology and accuracy. In large scale objects TLS is better in terms of quality and processing time.
OFF-LINE VS. ON-LINE CALIBRATION OF A PANORAMIC-BASED MOBILE MAPPING SYSTEM
Authors: Cannelle B. , Paparoditis N. , Pierrot-Deseilligny M. , Papelard J.-P.
Published: October 2012

Abstract. This paper presents two methods to calibrate a photogrammetric-based mobile mapping system. The paper is organised as follow. The first part presents the problem we are trying to solve, i.e. the calibration of multi-camera head on a mobile mapping system equipped with an Inertial Navigation System (INS). We want to estimate on the one hand the relative pose of images within the head and on the other hand the relative pose between the head and the INS The second part presents the first calibration method which is based on observations of a sub-millimeter accuracy topometric target network. The third part explores a method to determine the calibration on-line, i.e. using the images acquired during the surveys. The final section compare the two methods on an neutral data set and resumes the pros and cons of each method.
MULTIPLE-MODEL BASED VERIFICATION OF ROAD DATA
Authors: Ziems M. , Breitkopf U. , Heipke C. , Rottensteiner F.
Published: October 2012

Abstract. This paper describes a semi-automatic system for road verification based on high resolution imagery and 3D surface models. Potential update regions are identified by an object-wise verification of all existing database records. The proposed system combines several road detection and road verification approaches from current literature to form a more general solution. Each road detection / verification approach is realized as an independent module representing a unique road model combined with a corresponding processing strategy. The object-wise verification result of each module is formulated as a binary decision between the classes "correct road" and "incorrect road". These individual decisions are combined by Dempster-Shafer fusion, which provides tools for dealing with uncertain and incomplete knowledge about the statistical properties of the data. For each road detection / verification module a confidence function for the result is introduced that reflects the degree of correspondence of an actual test situation with an optimal situation according to the underlying road model of that module. A comparison with results from an EuroSDR test on road extraction demonstrate the strengths and limitations of the method.
COMPLEX EVENT DETECTION IN PEDESTRIAN GROUPS FROM UAVS
Authors: Burkert F. , Butenuth M.
Published: October 2012

Abstract. We present a new hierarchical event detection approach for highly complex scenarios in pedestrian groups on the basis of airborne image sequences from UAVs. Related work on event detection for pedestrians is capable of learning and analyzing recurring motion paths to detect abnormal paths and of analyzing the type of motion interaction between pairs of pedestrians. However, these approaches can only describe basic motion and fail at the analysis of pedestrian groups with complex behavior. We overcome the limitations of the related work by using a dynamic pedestrian graph of a scene which contains basic pairwise pedestrian motion interaction labels in the first layer. In the second layer, pedestrian groups are analyzed based on the dynamic pedestrian graph in order to get higher-level information about group behavior. This is done by a heuristic assignment of predefined scenarios out of a model library to the data. The assignment is based on the motion interaction labels, on dynamic group motion parameters and on a set of subgraph features. Experimental results are shown based on a new UAV dataset which contains group motion of different complexity levels.
DETECTING AND CORRECTING MOTION BLUR FROM IMAGES SHOT WITH CHANNEL-DEPENDENT EXPOSURE TIME
Authors: Lelégard L. , Delaygue E. , Brédif M. , Vallet B.
Published: October 2012

Abstract. This article describes a pipeline developed to automatically detect and correct motion blur due to the airplane motion in aerial images provided by a digital camera system with channel-dependent exposure times. Blurred images show anisotropy in their Fourier Transform coefficients that can be detected and estimated to recover the characteristics of the motion blur. To disambiguate the anisotropy produced by a motion blur from the possible spectral anisotropy produced by some periodic patterns present in a sharp image, we consider the phase difference of the Fourier Transform of two channel shot with different exposure times (i.e. with different blur extensions). This is possible because of the deep correlation between the three visible channels ensures phase coherence of the Fourier Transform coefficients in sharp images. In this context, considering the phase difference constitutes both a good detector and estimator of the motion blur parameters. In order to improve on this estimation, the phase difference is performed on local windows in the image where the channels are more correlated. The main lobe of the phase difference, where the phase difference between two channels is close to zero actually imitates an ellipse which axis ratio discriminates blur and which orientation and minor axis give respectively the orientation and the blur kernel extension of the long exposure-time channels. However, this approach is not robust to the presence in the phase difference of minor lobes due to phase sign inversions in the Fourier transform of the motion blur. They are removed by considering the polar representation of the phase difference. Based on the blur detection step, blur correction is eventually performed using two different approaches depending on the blur extension size: using either a simple frequency-based fusion for small blur or a semi blind iterative method for larger blur. The higher computing costs of the latter method make it only suitable for large motion blur, when the former method is not applicable.
INTEGRATION OF VIDEO IMAGES AND CAD WIREFRAMES FOR 3D OBJECT LOCALIZATION
Authors: Persad R. A. , Armenakis C. , Sohn G.
Published: October 2012

Abstract. The tracking of moving objects from single images has received widespread attention in photogrammetric computer vision and considered to be at a state of maturity. This paper presents a model-driven solution for localizing moving objects detected from monocular, rotating and zooming video images in a 3D reference frame. To realize such a system, the recovery of 2D to 3D projection parameters is essential. Automatic estimation of these parameters is critical, particularly for pan-tilt-zoom (PTZ) surveillance cameras where parameters change spontaneously upon camera motion. In this work, an algorithm for automated parameter retrieval is proposed. This is achieved by matching linear features between incoming images from video sequences and simple geometric 3D CAD wireframe models of man-made structures. The feature matching schema uses a hypothesis-verify optimization framework referred to as LR-RANSAC. This novel method improves the computational efficiency of the matching process in comparison to the standard RANSAC robust estimator. To demonstrate the applicability and performance of the method, experiments have been performed on indoor and outdoor image sequences under varying conditions with lighting changes and occlusions. Reliability of the matching algorithm has been analyzed by comparing the automatically determined camera parameters with ground truth (GT). Dependability of the retrieved parameters for 3D localization has also been assessed by comparing the difference between 3D positions of moving image objects estimated using the LR-RANSAC-derived parameters and those computed using GT parameters.
SEMI-SUPERVISED MARGINAL FISHER ANALYSIS FOR HYPERSPECTRAL IMAGE CLASSIFICATION
Authors: Huang H. , Liu J. , Pan Y.
Published: October 2012

Abstract. The problem of learning with both labeled and unlabeled examples arises frequently in Hyperspectral image (HSI) classification. While marginal Fisher analysis is a supervised method, which cannot be directly applied for Semi-supervised classification. In this paper, we proposed a novel method, called semi-supervised marginal Fisher analysis (SSMFA), to process HSI of natural scenes, which uses a combination of semi-supervised learning and manifold learning. In SSMFA, a new difference-based optimization objective function with unlabeled samples has been designed. SSMFA preserves the manifold structure of labeled and unlabeled samples in addition to separating labeled samples in different classes from each other. The semi-supervised method has an analytic form of the globally optimal solution, and it can be computed based on eigen decomposition. Classification experiments with a challenging HSI task demonstrate that this method outperforms current state-of-the-art HSI-classification methods.
EXTRACTION OF VINEYARDS OUT OF AERIAL ORTHO-IMAGE USING TEXTURE INFORMATION
Authors: Le Bris A.
Published: October 2012

Abstract. A cartography of vineyards is required by many mapping agencies, both to draw topographic maps and to complete the "vineyard" layer of large scale land cover databases. In this paper, two distinct approaches are proposed and tested to achieve a (semi-)automatic detection of vineyards task out of 50cm ground resolution ortho-images. Both are object based approaches relying on image texture analysis in homogeneous land cover regions. Therefore, the first step (common to both approaches) is a segmentation of the image into homogeneous land cover regions. These regions can then be classified as vineyards or not by the next approaches. A first approach consists in a frequency analysis of the image texture in each region. A semi-variogram is first calculated from the ortho-image for each region of the segmentation. A Fourier transform (FFT) of this semi-variogram of the image is then considered. If a periodic signal with a high frequency (i.e. of which the frequency is upper than a threshold) is identified, the region is labelled as a vineyard. The second approach is a supervised (per region) land cover classification one. It uses texture indexes calculated from ortho-images as input image information. In particular, some texture indexes derived from SIFT descriptors calculated from ortho-images have been used in the experiments, giving good results.
EVALUATION OF CORRECTION METHODS OF CHROMATIC ABERRATION IN DIGITAL CAMERA IMAGES
Authors: Matsuoka R. , Asonuma K. , Takahashi G. , Danjo T. , Hirana K.
Published: October 2012

Abstract. This paper reports an experiment conducted to evaluate correction methods of chromatic aberrations in images acquired by a nonmetric digital camera. The chromatic aberration correction methods evaluated in the experiment are classified into two kinds. One is the method to correct image coordinates by using camera calibration results of color-separated images. The other is the method based on the assumption that the magnitude of chromatic aberrations can be expressed by a function of a radial distance from the center of an image frame. The former is classified further into five types according to the difference of orientation parameters common to all colors. The latter is classified further into three types according to the order of the correction function. We adopt a linear function, a quadratic function and a cubic function of the radial distance as a correction function. We utilize a set of 16 convergent images shooting a white sheet with 10 by 10 black filled circles to carry out camera calibration and estimate unknown coefficients in the correction function by means of least squares adjustment. We evaluate the chromatic aberration correction methods by using a normal image shooting a white sheet with 14 by 10 black filled circles. From the experiment results, we conclude that the method based on the assumption that the magnitude of chromatic aberrations can be expressed by a cubic function of the radial distance is the best method of the evaluated methods, and would be able to correct chromatic aberrations satisfactorily enough in many cases.
REAL-TIME CAMERA GUIDANCE FOR 3D SCENE RECONSTRUCTION
Authors: Schindler F. , Förstner W.
Published: October 2012

Abstract. We propose a framework for operator guidance during the image acquisition process for reliable multi-view stereo reconstruction. Goal is to achieve full coverage of the object and sufficient overlap. Multi-view stereo is a commonly used method to reconstruct both camera trajectory and 3D object shape. After determining an initial solution, a globally optimal reconstruction is usually obtained by executing a bundle adjustment involving all images. Acquiring suitable images, however, still requires an experienced operator to ensure accuracy and completeness of the final solution. We propose an interactive framework for guiding unexperienced users or possibly an autonomous robot. Using approximate camera orientations and object points we estimate point uncertainties within a sliding bundle adjustment and suggest appropriate camera movements. A visual feedback system communicates the decisions to the user in an intuitive way. We demonstrate the suitability of our system with a virtual image acquisition simulation as well as in real-world scenarios. We show that when following the camera movements suggested by our system, the proposed framework is able to generate good approximate values for the bundle adjustment, leading to accurate results compared to ground truth after few iterations. Possible applications are non-professional 3D acquisition systems on low-cost platforms like mobile phones, autonomously navigating robots as well as online flight planning of unmanned aerial vehicles.
COMBINED MULTI-VIEW MATCHING ALGORITHM WITH LONG-STRIPS OF SATELLITE IMAGERY FROM DIFFERENT ORBITS
Authors: Xiong J. , Zhang Y.
Published: October 2012

Abstract. Existing matching algorithms aim to match conjugate points among overlapping satellite scenes acquired from the same orbit and can generally achieve good matching performance. Unfortunately, no algorithm can avoid the difficulty of simultaneously processing the data sets of long-strip imagery acquired from different orbits. In this paper, the combined matching algorithm we propose introduces the LBP/C operator, which, when combined with existing feature detectors for the first time, can make possible the extraction of more stable interest points and candidates. At the same time, based on the typical characteristics of Chinese satellite imagery, we improved the filter method and achieved an effective combination of several image matching algorithms. A comparison among several kinds of matching transfer modes was presented; and to evaluate this algorithm, Chinese Mapping Satellite-I data are used as the reference data.
STREAMED VERTICAL RECTANGLE DETECTION IN TERRESTRIAL LASER SCANS FOR FACADE DATABASE PRODUCTION
Authors: Demantké J. , Vallet B. , Paparoditis N.
Published: October 2012

Abstract. A reliable and accurate facade database would be a major asset in applications such as localization of autonomous vehicles, registration and fine building modeling. Mobile mapping devices now provide the data required to create such a database, but efficient methods should be designed in order to tackle the enormous amount of data collected by such means (a million point per second for hours of acquisition). Another important limitation is the presence of numerous objects in urban scenes of many different types. This paper proposes a method that overcomes these two issues: – The facade detection algorithm is streamed: the data is processed in the order it was acquired. More precisely, the input data is split into overlapping blocks which are analysed in turn to extract facade parts. Close overlapping parts are then merged in order to recover the full facade rectangle. – The geometry of the neighborhood of each point is analysed to define a probability that the point belongs to a vertical planar patch. This probability is then injected in a RANdom SAmple Consensus (RANSAC) algorithm both in the sampling step and in the hypothesis validation, in order to favour the most reliable candidates. This ensures much more robustness against outliers during the facade detection. This way, the main vertical rectangles are detected without any prior knowledge about the data. The only assumptions are that the facades are roughly planar and vertical. The method has been successfully tested on a large dataset in Paris. The facades are detected despite the presence of trees occluding large areas of some facades. The robustness and accuracy of the detected facade rectangles makes them useful for localization applications and for registration of other scans of the same city or of entire city models.
RAPID CHANGE DETECTION ALGORITHM FOR DISASTER MANAGEMENT
Authors: Michel U. , Thunig H. , Ehlers M. , Reinartz P.
Published: October 2012

Abstract. This paper focuses on change detection applications in areas where catastrophic events took place which resulted in rapid destruction especially of manmade objects. Standard methods for automated change detection prove not to be sufficient; therefore a new method was developed and tested. The presented method allows a fast detection and visualization of change in areas of crisis or catastrophes. While often new methods of remote sensing are developed without user oriented aspects, organizations and authorities are not able to use these methods because of absence of remote sensing know how. Therefore a semi-automated procedure was developed. Within a transferable framework, the developed algorithm can be implemented for a set of remote sensing data among different investigation areas. Several case studies are the base for the retrieved results. Within a coarse dividing into statistical parts and the segmentation in meaningful objects, the framework is able to deal with different types of change. By means of an elaborated Temporal Change Index (TCI) only panchromatic datasets are used to extract areas which are destroyed, areas which were not affected and in addition areas where rebuilding has already started.
DSM EXTRACTION AND EVALUATION FROM GEOEYE-1 STEREO IMAGERY
Authors: Saldaña M. M. , Aguilar M. A. , Aguilar F. J. , Fernández I.
Published: October 2012

Abstract. The newest very high resolution (VHR) commercial satellites, such as GeoEye-1 or WorldView-2, open new possibilities for cartographic applications, orthoimages generation and extraction of Digital Surface Models (DSMs). These DSMs are generated by image matching strategies from VHR satellite stereopairs imagery, reconstructing the 3D surface corresponding to the first surface view of the earth containing both microrelief (buildings, trees and so on) and bare terrain. The main aim of this work is to carry out an accuracy assessment test on the DSMs extracted from a GeoEye-1 stereopair captured in August 2011. A LiDAR derived DSM taken at the same month that the satellite imagery was used as ground truth. The influence of factors such as number of Ground Control Points (GCPs), sensor models tested and the geoid employed to transform the ellipsoid to orthometric heights were going to be evaluated. In this way, different sets of GCPs ranging from 7 to 45, two sensor models and two geoids (EGM96 and EGM08, the last adapted for Spain vertical network by the Spanish's National Geographic Institute) were tested in this work. The photogrammetric software package used was OrthoEngine from PCI Geomatica v. 10.3.2. OrthoEngine implements both sensor models tested: (i) the physical model developed by Toutin (CCRS) and, (ii) the rational function model using rational polynomial coefficients supplied by the vendor and later refined by means of the zero order linear functions (RPC0). When high accurate and well-distributed GCPs were used, the planimetric and vertical accuracies of DSMs generated from the GeoEye-1 Geo stereopair were always better than 0.5 m. Using only 7 GCPs and RPC0, a vertical accuracy around 0.43 m measured as standard deviation was attained. The geoid used by OrthoEngine (EGM96) produced similar results that the EGM08 adapted for Spain vertical network.
GRAPH-BASED URBAN LAND USE MAPPING FROM HIGH RESOLUTION SATELLITE IMAGES
Authors: Walde I. , Hese S. , Berger C. , Schmullius C.
Published: October 2012

Abstract. Due to the dynamic character of urban land use (e.g. urban sprawl) there is a demand for frequent updates for monitoring, modeling, and controlling purposes. Urban land use is an added value that can be indirectly derived with the help of various properties of land cover classes that describe a certain area and create a distinguishable structure. The goal of this project is to extract land use (LU) classes out of a structure of land cover (LC) classes from high resolution Quickbird data and additional LiDAR building height models. The study area is Rostock, a German city with more than 200.000 inhabitants. To model the properties of urban land use a graph based approach is adapted from other disciplines (industrial image processing, medicine, informatics). A graph consists of nodes and edges while nodes describe the land cover and edges define the relationship of neighboring objects. To calculate the adjacency that describes which nodes are combined with an edge several distance ranges and building height properties are tested. Furthermore the information value of planar versus non-planar graph types is analyzed. After creating the graphs specific indices are computed that evaluate how compact or connected the graphs are. In this work several graph indices are explained and applied to training areas. Results show that the distance of buildings and building height are reliable indicators for LU-categories. The separability of LU-classes improves when properties of land cover classes and graph indices are combined to a LU-signature.
AN EVALUATIVE REVIEW OF SIMULATED DYNAMIC SMART 3D OBJECTS
Authors: Romeijn H. , Sheth F. , Pettit C. J.
Published: October 2012

Abstract. Three-dimensional (3D) modelling of plants can be an asset for creating agricultural based visualisation products. The continuum of 3D plants models ranges from static to dynamic objects, also known as smart 3D objects. There is an increasing requirement for smarter simulated 3D objects that are attributed mathematically and/or from biological inputs. A systematic approach to plant simulation offers significant advantages to applications in agricultural research, particularly in simulating plant behaviour and the influences of external environmental factors. This approach of 3D plant object visualisation is primarily evident from the visualisation of plants using photographed billboarded images, to more advanced procedural models that come closer to simulating realistic virtual plants. However, few programs model physical reactions of plants to external factors and even fewer are able to grow plants based on mathematical and/or biological parameters. In this paper, we undertake an evaluation of plant-based object simulation programs currently available, with a focus upon the components and techniques involved in producing these objects. Through an analytical review process we consider the strengths and weaknesses of several program packages, the features and use of these programs and the possible opportunities in deploying these for creating smart 3D plant-based objects to support agricultural research and natural resource management. In creating smart 3D objects the model needs to be informed by both plant physiology and phenology. Expert knowledge will frame the parameters and procedures that will attribute the object and allow the simulation of dynamic virtual plants. Ultimately, biologically smart 3D virtual plants that react to changes within an environment could be an effective medium to visually represent landscapes and communicate land management scenarios and practices to planners and decision-makers.
GEOMETRICAL ADJUSTMENT TOWARDS THE ALIGNMENT OF VECTOR DATABASES
Authors: S. Dalyot  , T. Dahinden  , M. J. Schulze  , J. Boljen  , M. Sester
Published: October 2012

Abstract. Comparison of geospatial databases presenting similar spatial extent might show substantial differences. This is the consequence of different factors, such as: accuracy, scale, data collection and processing methods, level-of-detail, data models – to name a few. The differences are reflected in the geometric structure of objects, location, topology and the accompanying information. Geometric discrepancies are emerging, and sometimes even contradictions exist between the various data sources. Thus, the demand for processes that enable alignment of different data sources while maintaining spatial consistency is growing. Global solution strategies, such as an affine transformation, are incomplete solutions since discrepancies are still likely to exist due to the inability of such a global solution to account for the remaining errors due to local distortions. In order to account for the resulting random distortions, e.g., geometric conflicts, a localized geometric alignment process is implemented in this research. During this process the distortions (deviations) are quantified locally via sets of specifically selected observation constraints, to assure the spatial consistency of the vector data. This strategy exploits local spatial topologic and geometric relationships between corresponding line-features prior to the implementation of Least Squares Adjustment for the alignment, and observes local distortions and ambiguities that might exist. The outcome presents a significant improvement of the initial state by resolving local geometric distortions and discrepancies, suggesting a reliable solution for the problem on a statistically sound basis.
VIRTUAL CULTURAL LANDSCAPE LABORATORY BASED ON INTERNET GIS TECHNOLOGY
Authors: Bill R.
Published: October 2012

Abstract. In recent years the transfer of old documents (books, paintings, maps etc.) from analogue to digital form has gained enormous importance. Numerous interventions are concentrated in the digitalisation of library collections, but also commercial companies like Microsoft or Google try to convert large analogue stocks such as books, paintings, etc. in digital form. Data in digital form can be much easier made accessible to a large user community, especially to the interested scientific community. The aim of the described research project is to set up a virtual research environment for interdisciplinary research focusing on the landscape of the historical Mecklenburg in the north-east of Germany. Georeferenced old maps from 1786 and 1890 covering complete Mecklenburg should be combined with current geo-information, satellite and aerial imagery to support spatio-temporal research aspects in different scales in space (regional 1:200,000 to local 1:25.000) and time (nearly 250 years in three time steps, the last 30 years also in three time slices). The Virtual Laboratory for Cultural Landscape Research (VKLandLab) is designed and developed by the Chair of Geodesy and Geoinformatics, hosted at the Computing Centre (ITMZ) and linked to the Digital Library (UB) at Rostock University. VKLandLab includes new developments such as wikis, blogs, data tagging, etc. and proven components already integrated in various data-related infrastructures such as InternetGIS, data repositories and authentication structures. The focus is to build a data-related infrastructure and a work platform that supports students as well as researchers from different disciplines in their research in space and time.
ONLINE MAPS AND CLOUD-SUPPORTED LOCATION-BASED SERVICES ACROSS A MANIFOLD OF DEVICES
Authors: Kröpfl M. , Buchmüller D. , Leberl F.
Published: October 2012

Abstract. Online mapping, miniaturization of computing devices, the "cloud", Global Navigation Satellite System (GNSS) and cell tower triangulation all coalesce into an entirely novel infrastructure for numerous innovative map applications. This impacts the planning of human activities, navigating and tracking these activities as they occur, and finally documenting their outcome for either a single user or a network of connected users in a larger context. In this paper, we provide an example of a simple geospatial application making use of this model, which we will use to explain the basic steps necessary to deploy an application involving a web service hosting geospatial information and a client software consuming the web service through an API. The application allows an insurance claim specialist to add claims to a cloud-based database including a claim location. A field agent then uses a smartphone application to query the database by proximity, and heads out to capture photographs as supporting documentation for the claim. Once the photos have been uploaded to the web service, a second web service for image matching is called in order to try and match the current photograph to previously submitted assets. Image matching is used as a pre-verification step to determine whether the coverage of the respective object is sufficient for the claim specialist to process the claim. The development of the application was based on Microsoft's® Bing Maps™, Windows Phone™, Silverlight™, Windows Azure™ and Visual Studio™, and was completed in approximately 30 labour hours split among two developers.
EVALUATION OF ASTER GDEM VER2 USING GPS MEASUREMENTS AND SRTM VER4.1 IN CHINA
Authors: Li P. , Shi C. , Li Z. , Muller J.-P. , Drummond J. , Li X. , Li T. , Li Y. , Liu J.
Published: October 2012

Abstract. The freely available ASTER GDEM ver2 was released by NASA and METI on October 17, 2011. As one of the most complete high resolution digital topographic data sets of the world to date, the ASTER GDEM covers land surfaces between 83°N and 83°S at a spatial resolution of 1 arc-second and will be a useful product for many applications, such as relief analysis, hydrological studies and radar interferometry. The stated improvements in the second version of ASTER GDEM benefit from finer horizontal resolution, offset adjustment and water body detection in addition to new observed ASTER scenes. This study investigates the absolute vertical accuracy of the ASTER GDEM ver2 at five study sites in China using ground control points (GCPs) from high accuracy GPS benchmarks, and also using a DEM-to-DEM comparison with the Consultative Group for International Agriculture Research Consortium for Spatial Information (CGIAR-CSI) SRTM DEM (Version 4.1). And then, the results are separated into GlobCover land cover classes to derive the spatial pattern of error. It is demonstrated that the RMSE (19m) and mean (-13m) values of ASTER GDEM ver2 against GPS-GCPs in the five study areas is lower than its first version ASTER GDEM ver1 (26m and -21m) as a result of the adjustment of the elevation offsets in the new version. It should be noted that the five study areas in this study are representative in terms of terrain types and land covers in China, and even for most of mid-latitude zones. It is believed that the ASTER GDEM offers a major alternative in accessibility to high quality elevation data.
A STUDY OF URBAN INTENSIVE LAND EVALUATING SYSTEM
Authors: Jiang L. , Gu J. , Chen X. , You Y. , Tang Q.
Published: October 2012

Abstract. The contradiction of land supply and demand is becoming increasingly prominent in China. The increasing efficiency of land use is an important means to resolve the conflict. We propose a scientific approach for promoting the urban intensive land use. In this paper, an evaluation system of urban intensive land use is programmed. It is designed to change the manual way of collecting index data and building index system to a dynamical way. The system improves the efficiency and accuracy of the evaluation of urban intensive land use. It achieves intensive evaluation on three scales: macro-level, medium-level and micro-level. We build two data extraction methods. One is XML-based meta-data exchange method that obtains index data from the cadastral database. Another is data monitoring method that writes the index data to the evaluation database at real time. Database technologies are used to calculate index values and build index systems dynamically. GIS technologies are use to achieve three scales evaluation of urban intensive land use.
MONO-TEMPORAL GIS UPDATE ASSISTANCE SYSTEM BASED ON UNSUPERVISED COHERENCE ANALYSIS AND EVOLUTIONARY OPTIMISATION
Authors: Becker C. , Ostermann J. , Pahl M.
Published: October 2012

Abstract. Data in Geo Information Systems (GIS) is used for map services and various applications. Thus, quality assessment on a regular basis is required to keep the data up-to-date. In this paper we focus on one key reasons for updates: incorrect object borders. State of the art systems semi-automatically analyse up-to-date satellite image data to narrow down areas that have to be considered for GIS updates. Often resources are limited and only data from one point in time is available that is compared to the data. Rule based systems are required to bridge the gap between GIS specifications and results from image analysis. We present a system that can find areas of change without any manual configuration. Our approach automatically learns about important aspects of GIS specifications by analysing correct GIS objects. In potentially out-dated GIS data still a majority of objects is unchanged. Thus, we derive an model for normality (= correctness) by evaluating the coherence of relations between GIS objects and image analysis results. We synthesise changes at GIS object borders and analyse the impact on normality. In an evolutionary optimisation we determine areas of change that are rated with a significance value. We show that we can find 83% of all relevant update areas with a precision of 0.18, not considering the significance of changes. Including significance we can push the precision to 0.26 while still finding 77% of all relevant update areas.
THREE-DIMENSIONAL MAPS FOR DISASTER MANAGEMENT
Authors: Bandrova T. , Zlatanova S. , Konecny M.
Published: October 2012

Abstract. Geo-information techniques have proven their usefulness for the purposes of early warning and emergency response. These techniques enable us to generate extensive geo-information to make informed decisions in response to natural disasters that lead to better protection of citizens, reduce damage to property, improve the monitoring of these disasters, and facilitate estimates of the damages and losses resulting from them. The maintenance and accessibility of spatial information has improved enormously with the development of spatial data infrastructures (SDIs), especially with second-generation SDIs, in which the original product-based SDI was improved to a process-based SDI. Through the use of SDIs, geo-information is made available to local, national and international organisations in regions affected by natural disasters as well as to volunteers serving in these areas. Volunteer-based systems for information collection (e.g., Ushahidi) have been created worldwide. However, the use of 3D maps is still limited. This paper discusses the applicability of 3D geo-information to disaster management. We discuss some important aspects of maps for disaster management, such as user-centred maps, the necessary components for 3D maps, symbols, and colour schemas. In addition, digital representations are evaluated with respect to their visual controls, i.e., their usefulness for the navigation and exploration of the information. Our recommendations are based on responses from a variety of users of these technologies, including children, geospecialists and disaster managers from different countries.
CONCEPTS, MODELS AND IMPLEMENTATION OF THE MARINE SPATIAL DATA INFRASTRUCTURE IN GERMANY (MDI-DE)
Authors: C. Rüh  , R. Bill
Published: October 2012

Abstract. In Germany currently the development of a marine data infrastructure takes place with the aim of merging information concerning the fields coastal engineering, hydrography and surveying, protection of the marine environment, maritime conservation, regional planning and coastal research. This undertaking is embedded in a series of regulations and developments on many administrative levels from which specifications and courses of action derive. To set up a conceptual framework for the marine data infrastructure (MDI-DE) scientists at the Professorship for Geodesy and Geoinformatics at Rostock University are building a reference model, evaluating meta-information systems and developing models to support common workflows in marine applications. The reference model for the marine spatial data infrastructure of Germany (MDI-DE) is the guideline for all developments inside this infrastructure. Because the undertaking is embedded in a series of regulations and developments this paper illustrates an approach on modelling a scenario for the Marine Strategy Framework Directive (MSFD) using the Unified Modelling Language (UML). Evaluating how other countries built their marine spatial infrastructures is of main importance, to learn where obstacles are and errors are likely to occur. To be able to look at other initiatives from a neutral point of view it is necessary to construct a framework for evaluation of marine spatial data infrastructures. Spatial data infrastructure assessment approaches were used as bases and were expanded to meet the requirements of the marine domain. As an international case-study this paper will look at Canada's Marine Geospatial Data Infrastructure (MGDI), COINAtlantic and GeoPortal.
DATABASE ORGANISATION IN A WEB-ENABLED FREE AND OPEN-SOURCE SOFTWARE (FOSS) ENVIRONMENT FOR SPATIO-TEMPORAL LANDSLIDE MODELLING
Authors: Das I. , Oberai K. , Sarathi Roy P.
Published: October 2012

Abstract. Landslides exhibit themselves in different mass movement processes and are considered among the most complex natural hazards occurring on the earth surface. Making landslide database available online via WWW (World Wide Web) promotes the spreading and reaching out of the landslide information to all the stakeholders. The aim of this research is to present a comprehensive database for generating landslide hazard scenario with the help of available historic records of landslides and geo-environmental factors and make them available over the Web using geospatial Free & Open Source Software (FOSS). FOSS reduces the cost of the project drastically as proprietary software's are very costly. Landslide data generated for the period 1982 to 2009 were compiled along the national highway road corridor in Indian Himalayas. All the geo-environmental datasets along with the landslide susceptibility map were served through WEBGIS client interface. Open source University of Minnesota (UMN) mapserver was used as GIS server software for developing web enabled landslide geospatial database. PHP/Mapscript server-side application serve as a front-end application and PostgreSQL with PostGIS extension serve as a backend application for the web enabled landslide spatio-temporal databases. This dynamic virtual visualization process through a web platform brings an insight into the understanding of the landslides and the resulting damage closer to the affected people and user community. The landslide susceptibility dataset is also made available as an Open Geospatial Consortium (OGC) Web Feature Service (WFS) which can be accessed through any OGC compliant open source or proprietary GIS Software.
A METHOD FOR TRUE ORTHOPHOTO GENERATION BASED ON PROJECTION AND ITERATION STRATEGY
Authors: Wang X. , Xie J.
Published: October 2012

Abstract. The conventional orthophotos always suffer from the problems of building lean and double mapping, due to the occluding of the buildings. This paper proposed a new occlusion detection method for true orthophoto generation. This method adopts the way of projecting roof and wall polygons to the ground horizontal planes, and obtains the occlusions by iteration strategy. Experiments with the color aerial image data of the city of Kunming shows that comparing to other two representative methods, this method can obtain more accurate results. Additionally, the neighboring images are used for occlusion compensation, and finally the true orthophoto is generated.
A STRUCTURE-BASED APPROACH FOR MATCHING ROAD JUNCTIONS WITH DIFFERENT COORDINATE SYSTEMS
Authors: Luana X.
Published: October 2012

Abstract. Effective matching algorithm of multi-source road networks is of vital importance for integration, updating and maintenance. In traditional matching methods, buffering and geometrical distances are basic strategies for potential matches searching, and the coordinate systems need to be similar. These methods may be invalid if the coordinate systems are unknown. Therefore, a novel approach of comparing the structures of urban road networks based on skeleton extraction is proposed in this paper. Firstly, the similarity measurement between junctions is described by a cluster comparison consisted with its neighbour junctions. And then the hierarchical strokes are recognized as a global structure to match, which eliminates the effect of the different coordinate systems. Finally, graphs converted from hierarchical skeletons of road network in different coordinate systems are compared and the most probable junction correspondences are established with maximum common subgraph algorithm. Based on the corresponding junctions, an affine transformation is able to be established between two unknown coordinate systems, and the remaining junctions matching will be conducted by traditional geometric methods. An experiment of matching road networks is carried out without any other geographic positional information. The result shows that no matter how significant the difference of coordinate systems are, it is still able to find the correct matches, which is impossible by traditional methods.