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International audience; The use of laser scanning techniques has become a common way to measure the real world. Millions of points could be generated by this system, which brings forth the problem of visualizing and eventually performing analyses on them. In the open source domain, various software packages exist to visualize 3D point clouds. However, most of these software packages do not allow the real-time rendering of large point clouds. Few of them also allow visualization in an immersive manner. The research aims to create an open source viewer for large 3D point clouds, which enables a dynamic and immersive visualization. In order to do so, rendering and point cloud management strategies must be implemented to avoid overloading the computer’s memory. The rendering is done using OpenGL engine by utilizing the graphic card’s memory in order to perform faster visualization. The program consists of a pre-processing stage in which the point cloud files are divided into quadtrees and then subsampled using the random tree sampling method. The visualization itself will calculate the distance between the point of view and the center of nodes generated by the pre-processing stage. The amount of points rendered within each node will depend on this distance; the farther away the node is from the point of view, the fewer points are rendered. A loading and unloading function enables the point cloud to be rendered dynamically. With the point cloud management algorithm implemented, the resulting program is able to load large point clouds generated by a mobile laser scanner using an ordinary computer. The resulting program as well as the source code will be available for the public due to its open source nature.

The concept of multidimensional database and OLAP are usually understood as a part of Business intelligence. The paper presents the design of multidimensional database for crime prevention containing aggregated data from various crime registers and many other different sources for population, unemployment, properties, health, facilities etc. ETL processes enable to harmonize, aggregate, anonymize and integrate data among different topics. Fact tables are interlinked due to several shared dimensions, especially geographical and temporal dimensions. The SW and GIS solution includes a map client and a dashboard panel to implement selected OLAP principles and to provide easy tools for exploring and understanding complex factors and impacts of changes, and finally also for strategic crime prevention.

This paper aims at detecting route information of GPS traces to represent spatial and temporal information of trips. A Bayesian belief network model is used to calculate the probability of a road matching a GPS log point. The algorithm incorporates road network topology, distance from trace nodes to road segments, the angle between two lines, direction difference, accuracy of measured GPS log point, and position of roads. GPS data collected in the Eindhoven region, The Netherlands, is used to examine the performance of this algorithm. Results based on a small sample show that the algorithm has a good performance in both processing efficiency and prediction accuracy of correctly identified instances. Prediction accuracy using a small sample is 87.02 %.

This paper describes an exploratory study regarding parking search behavior. Based on GPS tracks of 97 car trips, the temporal and spatial components of parking search behavior are investigated in more detail. The data collection took place in November 2012 in the city of Turnhout, Belgium. The paper presents the way the data collection has been organized, the way the data have been analyzed, and some findings of the study. It appears that GPS tracking can be used to investigate both the temporal and spatial aspects of parking search behavior. The average parking search time found in this study is 1 min and 18 s (approximately 14 % of the total travel time). The use of street segments for parking is influenced by distance to the city center, distance to nearest parking facility, presence of shops, and parking tariffs.

Currently the forest sector in Finland is looking towards the next generation's forest resource information systems. Information used in forest planning is currently collected by using an area-based approach (ABA) where airborne laser scanning (ALS) data are used to generalize field-measured inventory attributes over an entire inventory area. Inventories are typically updated at 10-year interval. Thus, one of the key challenges is the age of the inventory information and the cost-benefit trade-off between using the old data and obtaining new data. Prediction of future forest resource information is possible through growth modelling. In this paper, the error sources related to ALS-based forest inventory and the growth models applied in forest planning to update the forest resource information were examined. The error sources included (i) forest inventory, (ii) generation of theoretical stem distribution, and (iii) growth modelling. Error sources (ii) and (iii) stem from the calculations used for forest planning, and were combined in the investigations. Our research area, Evo, is located in southern Finland. In all, 34 forest sample plots (300 m(2)) have been measured twice tree-by-tree. First measurements have been carried out in 2007 and the second measurements in 2014 which leads to 7 year updating period. Respectively, ALS-based forest inventory data were available for 2007. The results showed that prediction of theoretical stem distribution and forest growth modelling affected only slightly to the quality of the predicted stem volume in short-term information update when compared to forest inventory error.