| 1. |
- Forsman, Mona, et al.
(författare)
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Estimation of tree stem attributes using terrestrial photogrammetry
- 2012
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Ingår i: International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. - : Copernicus Gesellschaft. ; 39-B5, s. 261-265
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The objective of this work was to create a method to measure stem attributes of standing trees on field plots in the forest using terrestrial photogrammetry. The primary attributes of interest are the position and the diameter at breast height (DBH).The developed method creates point clouds from image from three or more calibrated cameras attached to a calibrated rig. SIFT features in multiple images in combination with epipolar line filtering are used to make high quality matching in images with large amounts of similar features and many occlusions. After projection of the point cloud to a simulated ground plane, RANSAC filtering is applied, followed by circle fitting to the remaining points.To evaluate the algorithm, a camera rig of five Canon digital system cameras with a baseline of 123 cm and up to 40 cm offset in height was constructed. The rig was used in a field campaign at the Remningstorp forest test area in southern Sweden. Ground truth was collected manually by surveying and manual measurements.Initial results show estimated tree stem diameters within 10% of the ground truth. This suggest that terrestrial photogrammetry is a viable method to measure tree stem diameters on circular field plots.
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| 2. |
- Gilichinsky, Michael
(författare)
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Knowledge-based classification of land cover for the quality assessement of GIS database
- 2010
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Ingår i: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. - 1682-1750 .- 2194-9034. ; XXXVIII-4-8-2/W9, s. 217-222
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Valid classification of remotely sensed data is one of the most studied issues in the geoinformation science. In recent years knowledge-based approach to image analysis has been developing for assessment and improvement of traditional statistically-based image classification. Knowledge-based classification procedure integrates remote sensing imagery with ancillary geospatial information from GIS. Data about land cover stored in GIS database are usually subjected to an intensive change processes that diminish their relevance and include different types of discrepant information. Classification of land cover by up-to-date satellite imagery and automatic updating of GIS database allows revision of discrepant or erroneous data. The knowledge-based classification doesn’t require any assumptions regarding the data distribution and allows straightforward incorporation of ancillary data from GIS. Compared to traditional mapping approaches knowledge-based classification has the advantages of lower cost, area-wide coverage, and possibility to frequent updating. In perspective of large GIS maintenance the knowledge-based classification may contribute to detection of change and assist automatic updating of spatial databases. The objective of this study was to perform knowledge-based classification of land cover using satellite remote sensing data and GIS ancillary data. The selected target groups of land cover from the Israeli National GIS have been characterized spectrally by multispectral IKONOS data and geometrically by GIS data. The formalized knowledge about the target groups was incorporated into classification of remote sensing data. By means of classification results the discrepant land cover polygons have been detected and suggested for revision. Discussed are classification results and the analysis of detected discrepancies. The classification results have provided an indication of the utility of formalized knowledge for classification of land cover. The proposed method could be one possible approach to quality assessment and may contribute to automatic updating of existing spatial databases
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| 3. |
- Gilichinsky, Michael
(författare)
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Measurements of Morphometric Parameters From Digital Elevation Models
- 2010
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Ingår i: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. - 1682-1750 .- 2194-9034. ; 38-4-8, s. 138-145
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Konferensbidrag (refereegranskat)abstract
- The present research examines the measured morphometric values of monogenetic cinder cones in the Tolbachik volcanic field (Kluchevskaya volcanic group, Kamchatka). The cones were measured from digital elevation models derived from satellite data (ASTER and SRTM) and from digitized topographic maps. The GPS measurements of 85 locations were performed in the field to provide geodetic reference for DEM processing as well as to assess the accuracy of the DEM. A methodology for morphometric measurements on a DEM is proposed. The morphometric parameters derived from a DEM include the main characteristics that control the rate of degradational evolution of the cone: height, width and slope. The measured morphometric values were compared and accuracy assessment was carried out.Our study analyzes the morphometric values of four recent cinder cones formed during the last basaltic eruption in 1975-76, and of five older ones formed during the last 2000 years. We show that morphometric values obtained from a DEM are affected by the resolution change, and characteristics of the same cinder cone may vary in their values among DEMs of different resolutions. According to the results, the morphometry of the cinder cones can be well characterized by a DEM derived from remotely sensed data. The calculated morphometric parameters showed a correlation with the spatial resolution of the DEM and relative age of the cinder cones. All studied DEM (including coarse resolution SRTM) were found suitable for morphometric measurements under the constraint of spatial resolution.
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| 4. |
- Mosomtai, G., et al.
(författare)
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Characterizing movement patterns of nomadic pastoralists and their exposure to rift valley fever in Kenya
- 2023
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Ingår i: The international archives of the photogrammetry, remote sensing and spatial information sciences. - : Copernicus GmbH. - 1682-1750 .- 2194-9034. ; , s. 211-216
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Konferensbidrag (refereegranskat)abstract
- The role of animal movement in spreading infectious diseases is highly recognized by various legislations and institutions such as the World Organisation for Animal Health and the International Animal Health Code. The increased interactions at the nexus of human-animal-ecosystem interface have seen an unprecedented introduction and reintroduction of new zoonotic diseases with high socio-economic impacts such as the COVID-19 pandemic. Rift Valley fever (RVF) is a zoonotic disease that affects both humans and animals and is transmitted by Aedes mosquitoes or through contact with the body fluids of infected animals. This study seeks to characterize movement patterns of pastoralist and how this movement behaviour increases their susceptibility to RVF virus exposure. We levarage on a rapidly growing field of movement ecology to monitor five herds collared from 2013 - 2015 in an RVF endemic semi-arid region in Kenya. The herds were also sampled for RVF antibodies to assess their exposure to RVF virus during the rainy seasons. adehabitatLT package in R was used to analyze the trajectory data whereas the first passage time (FPT) analysis was used to measure the area utilized in grazing. Sedentary herds grazed within 15km radius while migrating herds presented restricted space use patterns during the dry seasons and transient movement during the start and end of the rainy season. Furthermore, RVF virus antibodies were generally low for sedentary herds whereas the migrating herds recorded high levels during their transition periods. This study can be used to identify RVF risk zones for timely and targeted management strategies.
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| 5. |
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| 6. |
- Persson, Henrik
(författare)
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Body of Knowledge for the Earth Observation and Geoinformation Sector – A Basis for Innovative Skills Development
- 2020
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Ingår i: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. - 1682-1750 .- 2194-9034. ; XLIII-B5-2020, s. 15-22
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Konferensbidrag (refereegranskat)abstract
- With new Earth Observation (EO) and Geoinformation (GI) data sources increasingly becoming available, evermore new skills for data collection, processing, analysis and application are required. They are needed not only from scientists, but also from practitioners working in businesses, public and private EO*GI and related sectors. Aligning the continuously evolving skill sets demanded by the market and existing academic and vocational training programmes is not an easy task. Training programmes should be grounded in real needs of the sector and its labour market. To do this, it is necessary to identify the knowledge and skills needed, and map their interconnectivity in specific frameworks, which can later be used for the definition of new curricula or job-oriented learning paths. This paper presents a framework for the EO*GI sector, based on a Body of Knowledge (BoK), by creating a complete set of concepts with a semantic structure underneath that supports academia and industry. Creating and updating the BoK is supported by an editing tool, the Living Textbook and by experts in the EO*GI domain, who contributes to the BoK’s enrichment.
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| 7. |
- Persson, Henrik
(författare)
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Estimating the forest stand volume and basal area using pleiades spectral and auxiliary data
- 2019
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Ingår i: The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. - 1682-1750 .- 2194-9034. ; XLII-4/W18, s. 1131-1136
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Konferensbidrag (refereegranskat)abstract
- The aim of this study was to evaluate the improvements of volume and basal area estimations, when spectral data from the Pleiades were complemented with auxiliary data. The study area was located in the Darabkola's forest of Sari, Iran. In-situ data were collected for 144 circular sample plots, with 17.84 m radius, which were distributed using a simple random sampling design. Tree information included diameter at breast height (DBH) of all trees within the sample plots, and the height of some trees. By using DBH and tree height, the volume and basal area per hectare was also computed for each plot. Geometric and radiometric corrections of spectral data were applied to the images. In addition, the auxiliary maps of slope, aspect, elevation, soil pH and texture (through ground sampling and interpolation), precipitation and temperature (through interpolation of climate stations) were prepared. Digital values corresponding to ground plots were extracted from spectral bands and auxiliary data and considered as independent variables while volume and basal area were selected as dependent variables. The forest modeling was carried out using a non-parametric method of random forest (RF), using 70% of the sample plots as training data. The results were validated using the remaining 30% sample plots. The results indicated that by using both spectral and auxiliary data, the RMSE was reduced by 5% compared to using only spectral data for volume modeling. The corresponding advantage of using both spectral and auxiliary data was 1% to 3% when basal area was modeled.
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| 8. |
- Buchwitz, M., et al.
(författare)
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The greenhouse gas project of Esa's climate change initiative (GHG-CCI) : Overview, achievements and future plans
- 2015. - 7W3
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Ingår i: 2015 36th International Symposium on Remote Sensing of Environment. - 1682-1750. ; 40, s. 165-172
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Konferensbidrag (refereegranskat)abstract
- The GHG-CCI project (http://www.esa-ghg-cci.org/) is one of several projects of the European Space Agency's (ESA) Climate Change Initiative (CCI). The goal of the CCI is to generate and deliver data sets of various satellite-derived Essential Climate Variables (ECVs) in line with GCOS (Global Climate Observing System) requirements. The "ECV Greenhouse Gases" (ECV GHG) is the global distribution of important climate relevant gases-namely atmospheric CO2 and CH4-with a quality sufficient to obtain information on regional CO2 and CH4 sources and sinks. The main goal of GHG-CCI is to generate long-term highly accurate and precise time series of global near-surface-sensitive satellite observations of CO2 and CH4, i.e., XCO2 and XCH4, starting with the launch of ESA's ENVISAT satellite. These products are currently retrieved from SCIAMACHY/ENVISAT (2002-2012) and TANSO-FTS/GOSAT (2009-today) nadir mode observations in the near-infrared/shortwave-infrared spectral region. In addition, other sensors (e.g., IASI and MIPAS) and viewing modes (e.g., SCIAMACHY solar occultation) are also considered and in the future also data from other satellites. The GHG-CCI data products and related documentation are freely available via the GHG-CCI website and yearly updates are foreseen. Here we present an overview about the latest data set (Climate Research Data Package No. 2 (CRDP#2)) and summarize key findings from using satellite CO2 and CH4 retrievals to improve our understanding of the natural and anthropogenic sources and sinks of these important atmospheric greenhouse gases. We also shortly mention ongoing activities related to validation and initial user assessment of CRDP#2 and future plans.
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| 9. |
- Ellul, C., et al.
(författare)
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Investigating the state of play of geobim across Europe
- 2018. - 4/W10
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Ingår i: 13th 3D GeoInfo Conference 2018. - 1682-1750. ; 42, s. 19-26
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Konferensbidrag (refereegranskat)abstract
- In both the Geographic Information (Geo) and Building Information Modelling (BIM) domains, it is widely acknowledged that the integration of data from both domains is beneficial and a crucial step in facing the multi-disciplinary challenges of our built environment. The result of this integration - which can broadly be termed GeoBIM -could answer questions such as identifying an appropriate Heating, Ventilation and Air Conditioning system for a building based on room usage, outside air temperature, solar exposure and traffic pollution or validating whether a proposed built asset meets relevant planning constraints. Developing a coherent approach to GeoBIM integration requires consensus between multiple stakeholders from both the Geo and the BIM side and at an international level. This multi-country and multi-stakeholder approach is the topic of a 2-year EuroSDR project on GeoBIM integration that started in November 2017. The general aim of the project is to detail both the needs and the issues of GeoBIM integration, studied from use cases as well as from existing experiences in the participating countries and to develop initial solutions accordingly. This paper reports initial results - it identifies strong potential for GeoBIM but also rather fragmented activity, with no national level focus. It also notes that research (both in industry and academia) primarily focuses on standards, interoperability and data integration or exchange. Based on these findings - and with a focus on existing work and topics of interest to NMCAs - the next phase of the work will develop more detailed case studies for Asset Management and Urban Planning.
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| 10. |
- Ellul, C., et al.
(författare)
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THE EUROSDR GEOBIM PROJECT - DEVELOPING CASE STUDIES for the USE of GEOBIM in PRACTICE
- 2020. - 4/W1
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Ingår i: International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. - 1682-1750. ; 44, s. 33-40
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Konferensbidrag (refereegranskat)abstract
- Although the use of location-based data (location coupled with semantic information) within Geographical Information Systems (GIS) and from Earth Observation (e.g. satellite) sources has been long established for decision makers, this has only recently been reflected in the construction sector with a more recent move from Computer Aided Design (CAD) to Building Information Modelling. BIM has opened up an additional source of valuable location-based data, with particular focus on the architecture, structural and engineering detail of both buildings and infrastructure projects. As with most if not all location data, while BIM can be used on its own, major benefits are to be derived from integration with other data sources. When this is done with GIS, the result is known as GeoBIM and although there are some similarities between the two, challenges to integration are both technical and non technical, in particular the need for clear case studies to motivate both developers and senior management. There are synergies to be gained from a multi-national, coordinated approach when addressing these challenges, where participants can benefit from each-others' experience and where the needs of users and the National Mapping and Cadastral Agency (NMCA) perspective underpin the research. This paper summarises final outcomes and findings of the EuroSDR GeoBIM research project, which was set up to provide the required multi-national, user-centric collaborative framework, which had as its overall aim the development of best practice guidelines for GeoBIM, and due to its situation within EuroSDR has an NMCA focus. The paper updates information with regard to GeoBIM projects and maturity in the participant countries, and provides an overview of the two case studies developed.
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