Analyse räumlicher Daten mit GRASS GIS 7

Workshop zu den neuen Funktionen in GRASS GIS 7, ein freies und open source Geographisches Informationssystem (GIS) für Geodatenmanagement und -analyse, räumliche Modellierung und Visualisierung, Bildverarbeitung, und Kartenerstellung. Inhalt des Workshops ist, die analytischen Fähigkeiten von GRASS GIS anhand der neuen grafischen Benutzeroberfläche (Raster- und topologische Vektordatenanalyse, LiDAR-Datenverarbeitung) in einfachen, praktischen Schritten zu lernen. In diesem Workshop zeigen wir die neuen Funktionen in GRASS GIS 7 (http://grass.osgeo.org/grass7/). In einfachen, praktischen Schritten erlernen die Teilnehmer die analytischen Fähigkeiten von GRASS GIS anhand der neuen grafischen Benutzeroberfläche. Es werden Raster- und topologische Vektordatenanalyse gezeigt und auch einfache LiDAR-Datenverarbeitung erläutert. Am Schluss der Sitzung gibt es eine Kurzübersicht zu den Neuigkeiten der Version 7 (http://trac.osgeo.org/grass/wiki/Grass7/NewFeatures). GRASS GIS 7 ist ein freies und open source Geographisches Informationssystem (GIS) für Geodatenmanagement und -analyse, räumliche Modellierung und Visualisierung, Bildverarbeitung, und Kartenerstellung, das auf MS-Windows, Mac OSX, Linux und auch Supercomputern läuf

SWISS-TIGER: Assessing the potential distribution of the tiger mosquito Aedes albopictus in Switzerland. Technical report FEM-CRI PGIS

The Asian tiger mosquito (Aedes albopictus) is an efficient vector of at least 22 arboviruses, among them dengue and chikungunya viruses. This invasive species has been introduced to Europe as well as Africa and the American, Indo-Pacific and Australian regions. Changes in the pattern of distribution of the tiger mosquito may affect the potential spread of infectious diseases transmitted by this species. In Europe, the tiger mosquito is well established in Mediterranean countries. As of 2011, the tiger mosquito has been observed as far north as the Netherlands. In Switzerland, the tiger mosquito has invaded the canton Ticino. In the near future, the tiger mosquito might invade Switzerland also from the West in the Geneva area. Therefore, predicting areas suitable for future establishment and spread is essential for planning early prevention and control strategies

Spatio-temporal variations in chlorophyll-a concentration in the Patagonic continental shelf: an example of satellite time series processing with GRASS GIS temporal modules

The planktonic microscopic and photosynthesizing organisms inhabiting oceans, globally called phytoplankton, constitute the basis of all oceanic food webs and play a fundamental role in carbon cycling and biogeochemical cycles. Changes in phytoplankton biomass have significant impacts on all the biological, physical and geochemical processes occurring in the aquatic system. Therefore, there has been a rising interest in studying, monitoring, and understanding these variations and their timing at the regional and global scales. Since algae have photosynthetic pigments, such as chlorophyll-a, that absorb and reflect sun light mainly in the visible part of the electromagnetic spectrum, phytoplankton is capable of changing the optical properties of surrounding water, that is the ocean color. This principle allows to estimate chlorophyll-a concentration (proxy for phytoplankton biomass) through measures of the reflected radiation from the upper ocean layer by means of remote sensing. The objective of this study was to analyze the spatio-temporal variations of satellite chlorophyll-a concentration (chl-a) and phytoplankton blooms in the continental shelf and shelf break of the Argentinian patagonic region using the newly implemented temporal modules of GRASS GIS

Climatic suitability of Aedes albopictus in Europe referring to climate change projections: comparison of mechanistic and correlative niche modelling approaches

The Asian tiger mosquito, Aedes albopictus, is capable of transmitting a broad range of viruses to humans. Since its introduction at the end of the 20th century, it has become well established in large parts of southern Europe. As future expansion as a result of climate change can be expected, determining the current and projected future climatic suitability of this invasive mosquito in Europe is of interest. Several studies have tried to detect the potential habitats for this species, but differing data sources and modelling approaches must be considered when interpreting the findings. Here, various modelling methodologies are compared with special emphasis on model set-up and study design. Basic approaches and model algorithms for the projection of spatio-temporal trends within the 21st century differ substantially. Applied methods range from mechanistic models (e.g. overlay of climatic constraints based on geographic information systems or rather process-based approaches) to correlative niche models. We conclude that spatial characteristics such as introduction gateways and dispersal pathways need to be considered. Laboratory experiments addressing the climatic constraints of the mosquito are required for improved modelling results. However, the main source of uncertainty remains the insufficient knowledge about the species´ ability to adapt to novel environment

Fourier transforms for detecting multitemporal landscape fragmentation by remote sensing

Remote sensing is a useful tool for detecting landscape fragmentation, typically by creating land-use maps from remotely sensed images acquired at different dates. Nonetheless, classification may present a number of drawbacks since it degrades the information content of images leading to the loss of continuous information about fragmentation processes. For exploratory purposes, methods to detect landscape change based on continuous information should not require any a-priori assumptions about landscape characteristics. Accordingly, Fourier transforms may represent the best algorithmic solution. In this paper, we describe a Fourier transform tool developed in a free and open-source environment to detect potential fragmentation over the landscape. We briefly introduce Fourier transforms applied to remotely sensed imagery by further showing their potential application with an empirical example. We argue that Fourier transforms represent a straightforward approach for detecting spatial fragmentation of the landscape, on the strength of their potential to detect trends in increase or decrease of complexity/heterogeneity of the landscape in an objective manner. To our knowledge, this is the first open-source tool for analysing fragmentation of the landscape in multitemporal series based on Fourier transforms, which guarantees a high robustness and reproducibility of the applied algorithm

The STEM project: an open source solution for agricoltural monitoring

The STEM project, funded by the Autonomous Province of Trento (Italy) aims at implementing algorithms and tools for the efficient processing of remotely sensed data for forestry and agricultural applications. All the implemented tools are integrated in the open source Q-GIS software using a dedicated plug-in developed in the project. External open source libraries such as GRASS and R, as well as in-house algorithms, are integrated in the plug-in in order to fulfil all the required functionalities of the systems. All the algorithms were developed to use already available data as input and to prevent the additional costs of further acquisitions. Supervised classification algorithms and well-tested procedures were chosen in order to assure the maximum reliability and stability of the provided results in every operative condition. The final goal is the development of a turn- key systems for public administration technicians allowing easy and transparent classification of wide areas and their simple query to define the land use and in particular the orchard and plantation typologie

Estimación preliminar de áreas de mayor riesgo de Síndrome Pulmonar por Hantavirus en Argentina

El Síndrome Pulmonar por Hantavirus (SPH) es una enfermedad severa y algunas veces fatal causada por virus de la familia Bunyaviridae. Cada hantavirus es normalmente hospedado por una única especie de roedor perteneciente a la subfamilia Sigmodontinae. En Argentina se reconocen 4 regiones endémicas para SPH: Noroeste (Salta y Jujuy), Nordeste (Formosa y Misiones), Centro (Buenos Aires, Santa Fe y Entre Ríos) y Sur (Neuquén, Río Negro, Chubut y Santa Cruz). Estas regiones difieren en sus características ambientales, los virus circulantes, los huéspedes y el número de casos. Los mapas de riesgo basados en especies huéspedes son una práctica básica y esencial; no tan comunes, sin embargo, son los mapas basados en datos de infección o casos humanos de enfermedad. El objetivo de este estudio es modelar y mapear la distribución de casos de SPH en Argentina como función de variables climáticas y ambientales, para definir y estimar las áreas de mayor riesgo para humanos, transfiriendo a la Salud Pública la información recabada al efecto de consolidar medidas de prevención y control de la enfermeda

Estimación preliminar de áreas de mayor riesgo de Síndrome Pulmonar por Hantavirus en Argentina

El Síndrome Pulmonar por Hantavirus (SPH) es una enfermedad severa y algunas veces fatal causada por virus de la familia Bunyaviridae. Cada hantavirus es normalmente hospedado por una única especie de roedor perteneciente a la subfamilia Sigmodontinae. En Argentina se reconocen 4 regiones endémicas para SPH: Noroeste (Salta y Jujuy), Nordeste (Formosa y Misiones), Centro (Buenos Aires, Santa Fe y Entre Ríos) y Sur (Neuquén, Río Negro, Chubut y Santa Cruz). Estas regiones difieren en sus características ambientales, los virus circulantes, los huéspedes y el número de casos. Los mapas de riesgo basados en especies huéspedes son una práctica básica y esencial; no tan comunes, sin embargo, son los mapas basados en datos de infección o casos humanos de enfermedad. El objetivo de este estudio es modelar y mapear la distribución de casos de SPH en Argentina como función de variables climáticas y ambientales, para definir y estimar las áreas de mayor riesgo para humanos, transfiriendo a la Salud Pública la información recabada al efecto de consolidar medidas de prevención y control de la enfermeda

First assessment of potential distribution and dispersal capacity of the emerging invasive mosquito Aedes koreicus in Northeast Italy

Background Invasive alien species represent a growing threat for natural systems, economy and human health. Active surveillance and responses that readily suppress newly established colonies are effective actions to mitigate the noxious consequences of biological invasions. However, when an exotic species establishes a viable population in a new area, predicting its potential spread is the most effective way to implement adequate control actions. Emerging invasive species, despite monitoring efforts, are poorly known in terms of behaviour and capacity to adapt to the new invaded range. Therefore, tools that provide information on their spread by maximising the available data, are critical. Methods We apply three different approaches to model the potential distribution of an emerging invasive mosquito, Aedes koreicus, in Northeast Italy: 1) an automatic statistical approach based on information theory, 2) a statistical approach integrated with prior knowledge, and 3) a GIS physiology-based approach. Each approach possessed benefits and limitations, and the required ecological information increases on a scale from 1 to 3. We validated the model outputs using the only other known invaded area in Europe. Finally, we applied a road network analysis to the suitability surface with the highest prediction power to highlight those areas with the highest likelihood of invasion. Results The GIS physiological-based model had the highest prediction power. It showed that localities currently occupied by Aedes koreicus represent only a small fraction of the potentially suitable area. Furthermore, the modelled niche included areas as high as 1500 m a.s.l., only partially overlapping with Aedes albopictus distribution. Conclusions The simulated spread indicated that all of the suitable portion of the study area is at risk of invasion in a relatively short period of time if no control policies are implemented. Stochastic events may further boost the invasion process, whereas competition with Aedes albopictus may limit it. According to our analysis, some of the major cities in the study area may have already been invaded. Further monitoring is needed to confirm this finding. The developed models and maps represent valuable tools to inform policies aimed at eradicating or mitigating Aedes koreicus invasion in Northeast Italy and Central Europe

Warming trends of perialpine lakes from homogenised time series of historical satellite and in-situ data

The availability of more than thirty years of historical satellite data is a valuable source which could be used as an alternative to the sparse in-situ data. We developed a new homogenised time series of daily day time Lake Surface Water Temperature (LSWT) over the last thirty years (1986–2015) at a spatial resolution of 1 km from thirteen polar orbiting satellites. The new homogenisation procedure implemented in this study corrects for the different acquisition times of the satellites standardizing the derived LSWT to 12:00 UTC. In this study, we developed new time series of LSWT for five large lakes in Italy and evaluated the product with in-situ data from the respective lakes. Furthermore, we estimated the long-term annual and summer trends, the temporal coherence of mean LSWT between the lakes, and studied the intra-annual variations and long-term trends from the newly developed LSWT time series. We found a regional warming trend at a rate of 0.017 °C yr −1 annually and 0.032 °C yr −1 during summer. Mean annual and summer LSWT temporal patterns in these lakes were found to be highly coherent. Amidst the reported rapid warming of lakes globally, it is important to understand the long-term variations of surface temperature at a regional scale. This study contributes a new method to derive long-term accurate LSWT for lakes with sparse in-situ data thereby facilitating understanding of regional level changes in lake's surface temperatur