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FOSS4G 2017 Full Conference Proceedings (papers and posters)
Schweik, Charles M; Zia, Mohammed; Anderson, Andy
This Conference Proceedings is a collection of outstanding papers and posters submitted to the Academic Program of the International Conference for Free and Open Source Software for Geospatial (FOSS4G), 14th to 19th August 2017 in Boston, U.S.A.
Volume Introduction Letter
Schweik, Charles M; Zia, Mohammed; Anderson, Andy
This Conference Proceedings is a collection of outstanding papers and posters submitted to the Academic Program of the International Conference for Free and Open Source Software for Geospatial (FOSS4G), 14th to 19th August 2017 in Boston, U.S.A.
Analyzing the performance of NoSQL vs. SQL databases for Spatial and Aggregate queries
Agarwal, Sarthak; Rajan, KS
Relational databases have been around for a long time and spatial databases have exploited this feature for close to two decades. The recent past has seen the development of NoSQL non-relational databases, which are now being adopted for spatial object storage and handling, too. While SQL databases face scalability and agility challenges and fail to take the advantage of the cheap memory and processing power available these days, NoSQL databases can handle the rise in the data storage and frequency at which it is accessed and processed - which are essential features needed in geospatial scenarios, which do not deal with a fixed schema(geometry) and fixed data size. This paper attempts to evaluate the performance of an existing NoSQL database 'MongoDB' with its inbuilt spatial functions with that of a SQL database with spatial extension 'PostGIS' for two problems – spatial and aggregate queries, across a range of datasets, with varying features counts. All the data in the analysis was processed In-memory and no secondary memory was used. Initial results suggest that MongoDB performs better by an average factor of 10x-25x which increases exponentially as the data size increases in both indexed and non-indexed operations. Given these results, NoSQL databases may be better suited for simultaneous multiple-user query systems including Web-GIS and mobile-GIS. Further studies are required to understand the full potential of NoSQL databases across various geometries and spatial query types.
A New Spatial Approach for Efficient Transformation of Equality - Generalized TSP to TSP
Zia, Mohammed; Cakir, Ziyadin; Seker, Dursun Zafer
The Equality - Generalized Travelling Salesman Problem (E-GTSP) asks to find a Hamiltonian cycle visiting each group exactly once, where each group represents a type of visiting node. This can represent a range of combinatorial optimization problem of NP-hard type like planning, logistics, etc. Its solution requires transformation of E-GTSP to TSP before solving it using a given TSP solver. This paper presents 5 different search-algorithms for optimal transformation which considers spatial spread of nodes of each group. Algorithms are tested over 15 cities with different street-network’s fractal-dimension for 5 instances of group-counts each. It’s observed that the R-Search algorithm, which selects nodes from each group depending upon their radial separation with respect to the start-end point, is the optimal search criterion among all other algorithms with a mean length error of 8.8%. This study will help developers and researchers to answer complex routing problems from a spatial perspective.
Development of an extension of GeoServer for handling 3D spatial data
Ryoo, Hyung-Gyu; Kim, Soojin; Kim, Joon-Seok; Li, Ki-Joune
Recently, several open source software tools such as CesiumJS and iTowns have been developed for dealing with 3-dimensional spatial data. These tools mainly focus on visualization of 3D spatial data based on WebGL. An open-sourced server capable of storing, sharing and querying 3D spatial data has not yet been developed. GeoServer, one of the representative open source spatial data servers, provides many powerful features. In particular, it supports connecting to and publishing spatial data from a variety of data sources. GeoServer also supports Web Feature Service (WFS), which is a standard protocol established by the Open Geospatial Consortium to request geospatial feature data. However, GeoServer provides functions only for two-dimensional geometry, so it provides few functions for handling 3D spatial data. Because JTS Topology Suite, which is an important component of GeoServer, does not support 3D spatial operations, it also does not support solid geometries. In this paper, we discuss extension modules of GeoServer that we have implemented to handle 3D spatial data. First, instead of JTS, our modules adopted a geometry model based on the ISO 19107 standard and support 3D spatial operations from the Simple Feature CGAL library. Based on this geometry model, we have implemented new internal data structures that represent spatial information from the Feature interface in GeoServer. Second, we also extended the DataStore module to handle and store 3D spatial information for several data sources such as GeoJSON, GML and PostGIS. Finally, we extended the WFS module to share 3D spatial data via GeoServer.