Papers by Oscar Martinez Rubi
Open Geospatial Data, Software and Standards, May 15, 2017
Background: In the last decade Photogrammetry has shown to be a valid alternative to LiDAR techni... more Background: In the last decade Photogrammetry has shown to be a valid alternative to LiDAR techniques for the generation of dense point clouds in many applications. However, dealing with large image sets is computationally demanding. It requires high performance hardware and often long processing times that makes the photogrammetric point cloud generation not suitable for mapping purposes at regional and national scale. These limitations are partially overcome by commercial solutions, thanks to the use of expensive and dedicated hardware. Nonetheless, a Free and Open-Source Software (FOSS) photogrammetric solution able to cope with these limitations is still missing. Methods: In this paper, the bottlenecks of the basic components of photogrammetric workflows-tie-points extraction, bundle block adjustment (BBA) and dense image matching-are tackled implementing FOSS solutions. We present distributed computing algorithms for the tie-points extraction and for the dense image matching. Moreover, we present two algorithms for decreasing the memory needs of the BBA. The various algorithms are deployed on different hardware systems including a computer cluster. Results and conclusions: The usage of the algorithms presented allows to process large image sets reducing the computational time. This is demonstrated using two different datasets.
Open Geospatial Data, Software and Standards
Background: In the last decade Photogrammetry has shown to be a valid alternative to LiDAR techni... more Background: In the last decade Photogrammetry has shown to be a valid alternative to LiDAR techniques for the generation of dense point clouds in many applications. However, dealing with large image sets is computationally demanding. It requires high performance hardware and often long processing times that makes the photogrammetric point cloud generation not suitable for mapping purposes at regional and national scale. These limitations are partially overcome by commercial solutions, thanks to the use of expensive and dedicated hardware. Nonetheless, a Free and Open-Source Software (FOSS) photogrammetric solution able to cope with these limitations is still missing. Methods: In this paper, the bottlenecks of the basic components of photogrammetric workflows-tie-points extraction, bundle block adjustment (BBA) and dense image matching-are tackled implementing FOSS solutions. We present distributed computing algorithms for the tie-points extraction and for the dense image matching. Moreover, we present two algorithms for decreasing the memory needs of the BBA. The various algorithms are deployed on different hardware systems including a computer cluster. Results and conclusions: The usage of the algorithms presented allows to process large image sets reducing the computational time. This is demonstrated using two different datasets.
Lecture Notes in Geoinformation and Cartography, 2016
Astronomy & Astrophysics, 2013
Aims. The aim of the LOFAR epoch of reionization (EoR) project is to detect the spectral fluctuat... more Aims. The aim of the LOFAR epoch of reionization (EoR) project is to detect the spectral fluctuations of the redshifted HI 21 cm signal. This signal is weaker by several orders of magnitude than the astrophysical foreground signals and hence, in order to achieve this, very long integrations, accurate calibration for stations and ionosphere and reliable foreground removal are essential. Methods. One of the prospective observing windows for the LOFAR EoR project will be centered at the north celestial pole (NCP). We present results from observations of the NCP window using the LOFAR highband antenna (HBA) array in the frequency range 115 MHz to 163 MHz. The data were obtained in April 2011 during the commissioning phase of LOFAR. We used baselines up to about 30 km. The data was processed using a dedicated processing pipeline which is an enhanced version of the standard LOFAR processing pipeline.
Published in International Journal of Digital Earth 9(12), 2016.
This article discusses the use ... more Published in International Journal of Digital Earth 9(12), 2016.
This article discusses the use of 3D technologies in digital earth applications (DEAs) to study complex sites. These are large areas containing objects with heterogeneous shapes and semantic information. The study proposes that DEAs should be modular, have multi-tier architectures, and be developed as Free and Open Source Software if possible. In DEAs requiring high reliability in the 3D measurements, point clouds are proposed as basis for the 3D Digital digital earth representation. For the development of DEAs, we propose to follow a workflow with four components: data acquisition and processing, data management, data analysis and data visualization. For every component, technological challenges of using 3D technologies are identified and solutions applied for a case study are presented. The case study is a modular 3D DEA developed for the archaeological project Mapping the Via Appia. The 3D DEA allows archaeologists to virtually analyze a complex study area.
Published in Digital Applications in Archaeology and Cultural Heritage 3(2), 2016.
The use of 3D... more Published in Digital Applications in Archaeology and Cultural Heritage 3(2), 2016.
The use of 3D technologies in archaeology and architectural history has grown enormously. Nowadays, 3D technologies are used to record, present, analyse and reconstruct archaeological sites. Since the used tools mostly originate from other domains, the developments are characterised as technology-driven rather than methodology-driven. The recent trend of Free and Open Source Software (FOSS) and the technological improvements of digital infrastructures are changing this. This article presents the development of a 3D Spatial Data Infrastructure (3D SDI) that allows archaeology and historical architecture researchers to analyse complex sites. For the development of the 3D SDI, IT literacy levels of the users, reusability of the tooling and the advantages of using FOSS are taken into account. The 3D SDI was developed for Mapping the Via Appia. An interdisciplinary team of archaeology experts and engineers have developed tailor-made 3D solutions to enhance the analysis and exploration of the Via Appia.
International Journal of Digital Earth, 2016
Digital Applications in Archaeology and Cultural Heritage, 2016
The use of 3D technologies in archaeology and architectural history has grown enormously. Nowaday... more The use of 3D technologies in archaeology and architectural history has grown enormously. Nowadays, 3D technologies are used to record, present, analyse and reconstruct archaeological sites. Since the used tools mostly originate from other domains, the developments are characterised as technology-driven rather than methodology-driven. The recent trend of Free and Open Source Software (FOSS) and the technological improvements of digital infrastructures are changing this. This article presents the development of a 3D Spatial Data Infrastructure (3D SDI) that allows archaeology and historical architecture researchers to analyse complex sites. For the development of the 3D SDI, IT literacy levels of the users, reusability of the tooling and the advantages of using FOSS are taken into account. The 3D SDI was developed for Mapping the Via Appia. An interdisciplinary team of archaeology experts and engineers have developed tailor-made 3D solutions to enhance the analysis and exploration of the Via Appia.
2015 IEEE 11th International Conference on e-Science, 2015
SIGSPATIAL Special, 2015
The popularity, availability and sizes of point cloud data sets are increasing, thus raising inte... more The popularity, availability and sizes of point cloud data sets are increasing, thus raising interesting data management and processing challenges. Various software solutions are available for the management of point cloud data. A benchmark for point cloud data management systems was defined and it was executed for several solutions. In this paper we focus on the solutions based on the column-store MonetDB, the generic out-of-the-box approach is compared with two alternative approaches that exploit the spatial coherence of the data to improve the data access and to minimize the storage requirements.
Computers & Graphics, 2015
Point cloud data are important sources for 3D geo-information. An inventory of the point cloud da... more Point cloud data are important sources for 3D geo-information. An inventory of the point cloud data management user requirements has been compiled using structured interviews with users from different background: government, industry and academia. Based on these requirements a benchmark has been developed to compare various point cloud data management solutions with regard to functionality and performance. The main test dataset is the second national height map of the Netherlands, AHN2, with 6 to 10 samples for every square meter of the country, resulting in 640 billion points. At the database level, a data storage model based on grouping the points in blocks is available in Oracle and PostgreSQL. This model is compared with the 'flat table' model, where each point is stored in a table row, in Oracle, PostgreSQL and the column-store MonetDB. In addition, the commonly used file-based solution Rapidlasso LAStools is used for comparison with the database solutions. The results of executing the benchmark on different platforms are presented as obtained during the increasingly challenging stages with more functionality and more data: mini (20 million points), medium (20 billion points), and full benchmark (the complete AHN2).
Research Memorandum 2015-1 (VU-FEWEB), Jan 2015
This article presents the steps that have been taken to develop a 3D GIS for ‘Mapping the Via App... more This article presents the steps that have been taken to develop a 3D GIS for ‘Mapping the Via Appia‘. This project investigates the area around the fifth and sixth miles of the Via Appia Antica. ‘Mapping the Via Appia’ aims to gain an insight into the Roman interventions in this suburban landscape. Applying multiple archaeological methods, it makes a thorough inventory of the archaeological remains from all eras. Concerning the size, complexity, and nature of the research area, a 3D GIS could play a significant part in the analysis and preservation of the data.
This article presents the pipeline that has been developed for the 3D GIS of the ‘Mapping the Via Appia’ project. The article provides insight into the complex technical steps that have to be taken in order to create a 3D GIS that can be used for analyses. Besides, it describes applications that can be developed in the future if an open and standards-based data infrastructure is being used.
Conference Presentations by Oscar Martinez Rubi
Poster presentation at CAA Siena 2015
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Papers by Oscar Martinez Rubi
This article discusses the use of 3D technologies in digital earth applications (DEAs) to study complex sites. These are large areas containing objects with heterogeneous shapes and semantic information. The study proposes that DEAs should be modular, have multi-tier architectures, and be developed as Free and Open Source Software if possible. In DEAs requiring high reliability in the 3D measurements, point clouds are proposed as basis for the 3D Digital digital earth representation. For the development of DEAs, we propose to follow a workflow with four components: data acquisition and processing, data management, data analysis and data visualization. For every component, technological challenges of using 3D technologies are identified and solutions applied for a case study are presented. The case study is a modular 3D DEA developed for the archaeological project Mapping the Via Appia. The 3D DEA allows archaeologists to virtually analyze a complex study area.
The use of 3D technologies in archaeology and architectural history has grown enormously. Nowadays, 3D technologies are used to record, present, analyse and reconstruct archaeological sites. Since the used tools mostly originate from other domains, the developments are characterised as technology-driven rather than methodology-driven. The recent trend of Free and Open Source Software (FOSS) and the technological improvements of digital infrastructures are changing this. This article presents the development of a 3D Spatial Data Infrastructure (3D SDI) that allows archaeology and historical architecture researchers to analyse complex sites. For the development of the 3D SDI, IT literacy levels of the users, reusability of the tooling and the advantages of using FOSS are taken into account. The 3D SDI was developed for Mapping the Via Appia. An interdisciplinary team of archaeology experts and engineers have developed tailor-made 3D solutions to enhance the analysis and exploration of the Via Appia.
This article presents the pipeline that has been developed for the 3D GIS of the ‘Mapping the Via Appia’ project. The article provides insight into the complex technical steps that have to be taken in order to create a 3D GIS that can be used for analyses. Besides, it describes applications that can be developed in the future if an open and standards-based data infrastructure is being used.
Conference Presentations by Oscar Martinez Rubi
This article discusses the use of 3D technologies in digital earth applications (DEAs) to study complex sites. These are large areas containing objects with heterogeneous shapes and semantic information. The study proposes that DEAs should be modular, have multi-tier architectures, and be developed as Free and Open Source Software if possible. In DEAs requiring high reliability in the 3D measurements, point clouds are proposed as basis for the 3D Digital digital earth representation. For the development of DEAs, we propose to follow a workflow with four components: data acquisition and processing, data management, data analysis and data visualization. For every component, technological challenges of using 3D technologies are identified and solutions applied for a case study are presented. The case study is a modular 3D DEA developed for the archaeological project Mapping the Via Appia. The 3D DEA allows archaeologists to virtually analyze a complex study area.
The use of 3D technologies in archaeology and architectural history has grown enormously. Nowadays, 3D technologies are used to record, present, analyse and reconstruct archaeological sites. Since the used tools mostly originate from other domains, the developments are characterised as technology-driven rather than methodology-driven. The recent trend of Free and Open Source Software (FOSS) and the technological improvements of digital infrastructures are changing this. This article presents the development of a 3D Spatial Data Infrastructure (3D SDI) that allows archaeology and historical architecture researchers to analyse complex sites. For the development of the 3D SDI, IT literacy levels of the users, reusability of the tooling and the advantages of using FOSS are taken into account. The 3D SDI was developed for Mapping the Via Appia. An interdisciplinary team of archaeology experts and engineers have developed tailor-made 3D solutions to enhance the analysis and exploration of the Via Appia.
This article presents the pipeline that has been developed for the 3D GIS of the ‘Mapping the Via Appia’ project. The article provides insight into the complex technical steps that have to be taken in order to create a 3D GIS that can be used for analyses. Besides, it describes applications that can be developed in the future if an open and standards-based data infrastructure is being used.