Kloch G.,Institute of Geodesy and Cartography |
Krynski J.,Institute of Geodesy and Cartography
International Association of Geodesy Symposia | Year: 2010
In the classical approach of planar representation of the Bouguer plate the terrain correction including all its components is always positive and quickly converges with growing radius of integration of topography heights referred to the Bouguer plate. When, however, the Bouguer plate is considered spherical, some components of the terrain correction as well as the resultant terrain correction may become negative. The terrain correction determined using spherical approach does not exhibit the evidence of convergence in distant zones with growing radius of integration. It makes thus difficult to determine the limitation for the area of integration of topography to compute the terrain correction of the required accuracy. The paper presents the results of research concerning the occurrence of negative components of the terrain correction and their contribution to the resultant terrain correction considering different range of roughness of topography. The convergence of the terrain correction with growing integration radius was investigated in both planar and spherical approach and the differences between the solutions obtained using those approaches were discussed. Special attention was paid to both analytical and empirical investigations of the convergence of the terrain correction when using spherical approach. Numerical tests were performed with the use of DTMs and of real data in a few test areas of Poland that are representative in terms of the variety of topography as well as with the use of simple artificial terrain models. © Springer-Verlag Berlin Heidelberg 2010.
Kowalik W.,Institute of Geodesy and Cartography |
Dabrowska-Zielinska K.,Institute of Geodesy and Cartography |
Meroni M.,European Commission - Joint Research Center Ispra |
Raczka T.U.,Institute of Geodesy and Cartography |
de Wit A.,Wageningen University
International Journal of Applied Earth Observation and Geoinformation | Year: 2014
In the period 1999-2009 ten-day SPOT-VEGETATION products of the Normalized Difference Vegetation Index (NDVI) and Fraction of Absorbed Photo synthetically Active Radiation (FAPAR) at 1 km spatial resolution were used in order to estimate and forecast the wheat yield over Europe. The products were used together with official wheat yield statistics to fine-tune a statistical model for each NUTS2 region, based on the Partial Least Squares Regression (PLSR) method. This method has been chosen to construct the model in the presence of many correlated predictor variables (10-day values of remote sensing indicators) and a limited number of wheat yield observations. The model was run in two different modalities:the "monitoring mode", which allows for an overall yield assessment at the end of the growing season,and the "forecasting mode", which provides early and timely yield estimates when the growing seasonis on-going. Performances of yield estimation at the regional and national level were evaluated using across-validation technique against yield statistics and the estimations were compared with those of a reference crop growth model. Models based on either NDVI or FAPAR normalized indicators achieved similar results with a minimal advantage of the model based on the FAPAR product. Best modelling results were obtained for the countries in Central Europe (Poland, North-Eastern Germany) and also Great Britain. By contrast, poor model performances characterize countries as follows: Sweden, Finland, Ireland, Portugal,Romania and Hungary. Country level yield estimates using the PLSR model in the monitoring mode, andthose of a reference crop growth model that do not make use of remote sensing information showed comparable accuracies. The largest estimation errors were observed in Portugal, Spain and Finland for both approaches. This convergence may indicate poor reliability of the official yield statistics in these countries. © 2014 Elsevier B.V.
Boschetti M.,CNR Institute for Electromagnetic Sensing of the Environment |
Nutini F.,CNR Institute for Electromagnetic Sensing of the Environment |
Nutini F.,University of Milan |
Brivio P.A.,CNR Institute for Electromagnetic Sensing of the Environment |
And 3 more authors.
ISPRS Journal of Photogrammetry and Remote Sensing | Year: 2013
Studies of the impact of human activity on vegetation dynamics of the Sahelian belt of Africa have been recently re-invigorated by new scientific findings that highlighted the primary role of climate in the drought crises of the 1970s-1980s. Time series of satellite observations revealed a re-greening of the Sahelian belt that indicates no noteworthy human effect on vegetation dynamics at sub continental scale from the 1980s to late 1990s. However, several regional/local crises related to natural resources occurred in the last decades despite the re-greening thus underlying that more detailed studies are needed. In this study we used time-series (1998-2010) of SPOT-VGT NDVI and FEWS-RFE rainfall estimates to analyse vegetation - rainfall correlation and to map areas of local environmental anomalies where significant vegetation variations (increase/decrease) are not fully explained by seasonal changes of rainfall. Some of these anomalous zones (hot spots) were further analysed with higher resolution images Landsat TM/ETM+ to evaluate the reliability of the identified anomalous behaviour and to provide an interpretation of some example hot spots. The frequency distribution of the hot spots among the land cover classes of the GlobCover map shows that increase in vegetation greenness is mainly located in the more humid southern part and close to inland water bodies where it is likely to be related to the expansion/intensification of irrigated agricultural activities. On the contrary, a decrease in vegetation greenness occurs mainly in the northern part (12°-15°N) in correspondence with herbaceous vegetation covers where pastoral and cropping practices are often critical due to low and very unpredictable rainfall. The results of this study show that even if a general positive re-greening due to increased rainfall is evident for the entire Sahel, some local anomalous hot spots exist and can be explained by human factors such as population growth whose level reaches the ecosystem carrying capacity as well as population displacement leading to vegetation recovery. © 2013 International Society for Photogrammetry and Remote Sensing, Inc.
Tran T.T.,Vietnam Academy of Science and Technology |
Nguyen T.Y.,Vietnam Academy of Science and Technology |
Duong C.C.,Institute of Geodesy and Cartography |
Vy Q.H.,Vietnam Academy of Science and Technology |
And 3 more authors.
Journal of Geodynamics | Year: 2013
The Red River Fault system has a special position in northern Vietnam, forming the boundary between Sunda and South China blocks. The other fault systems include the Dien Bien Phu, Da River and Son La faults. GPS technology has been used to measure recent tectonic activity along these fault zones during the recent years. It is for the first time when all measurement data have been analyzed by GAMIT/GLOBK to get the ITRF2000 solutions for point absolute motion rates of the study area. GPS data collected at 27 stations in northern Vietnam from 1994 to 2007 have shown that the southwestern and northeastern sides of the Red River Fault are moving eastward at the same rate of 34.5. ±. 1. mm/yr and southward, at slightly different velocities of 12. ±. 1. mm/yr and 13. ±. 1. mm/yr, respectively. © 2012 Elsevier Ltd.
Musial J.P.,University of Bern |
Musial J.P.,Institute of Geodesy and Cartography |
Husler F.,University of Bern |
Sutterlin M.,University of Bern |
And 2 more authors.
Atmospheric Measurement Techniques | Year: 2014
Derivation of probability estimates complementary to geophysical data sets has gained special attention over the last years. Information about a confidence level of provided physical quantities is required to construct an error budget of higher-level products and to correctly interpret final results of a particular analysis. Regarding the generation of products based on satellite data a common input consists of a cloud mask which allows discrimination between surface and cloud signals. Further the surface information is divided between snow and snow-free components. At any step of this discrimination process a misclassification in a cloud/snow mask propagates to higher-level products and may alter their usability.Within this scope a novel probabilistic cloud mask (PCM) algorithm suited for the 1 km1 km Advanced Very High Resolution Radiometer (AVHRR) data is proposed which provides three types of probability estimates between: cloudy/clear-sky, cloudy/snow and clearsky/ snow conditions. As opposed to th majority of available techniques which are usually based on the decision-tree approach in the PCM algorithm all spectral, angular and ancillary information is used in a single step to retrieve probability estimates from the precomputed look-up tables (LUTs). Moreover, the issue of derivation of a single threshold value for a spectral test was overcome by the concept of multidimensional information space which is divided into small bins by an extensive set of intervals. The discrimination between snow and ice clouds and detection of broken, thin clouds was enhanced by means of the invariant coordinate system (ICS) transformation. The study area covers a wide range of environmental conditions spanning from Iceland through central Europe to northern parts of Africa which exhibit diverse difficulties for cloud/snow masking algorithms. The retrieved PCM cloud classification was compared to the Polar Platform System (PPS) version 2012 and Moderate Resolution Imaging Spectroradiometer (MODIS) collection 6 cloud masks, SYNOP (surface synoptic observations) weather reports, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) vertical feature mask version 3 and to MODIS collection 5 snow mask. The outcomes of conducted analyses proved fine detection skills of the PCM method with results comparable to or better than the reference PPS algorithm.
Godah W.,Institute of Geodesy and Cartography |
Godah W.,University of Khartoum |
Krynski J.,Institute of Geodesy and Cartography
International Journal of Applied Earth Observation and Geoinformation | Year: 2015
Since 2010, a series of Global Geopotential Models (GGMs) based on Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) satellite gravimetry mission have been released. In this study, the GGMs based on approximately 12 months of GOCE satellite gravity gradiometry (SGG) data have been compared over the area of Sudan with the EGM08 and terrestrial data. Geoid heights and free-air gravity anomalies from four GOCE/GRACE satellite-only GGMs, and one GOCE/GRACE GGM combined with terrestrial/altimetric gravity data were compared with the corresponding ones obtained from the EGM08, terrestrial free-air gravity anomalies and GNSS/levelling data. The results reveal that geoid heights and free-air gravity anomalies obtained from the GOCE-based GGMs agree with the corresponding ones from the EGM08 truncated to d/o 200 with standard deviation of 18-20 cm, and 3.4-4.2 mGal, respectively. Their agreement with the terrestrial free-air gravity anomalies and the GNSS/levelling geoid heights, in terms of standard deviation is about 5.5 mGal, and about 50 cm, respectively. © 2013 Elsevier B.V.
Drachal J.,Institute of Geodesy and Cartography |
Kawel A.K.,Institute of Geodesy and Cartography
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2016
The article describes the possibility of developing an overall map of the selected area on the basis of publicly available data. Such a map would take the form designed by the author with the colors that meets his expectations and a content, which he considers to be appropriate. Among the data available it was considered the use of satellite images of the terrain in real colors and, in the form of shaded relief, digital terrain models with different resolutions of the terrain mesh. Specifically the considered data were: MODIS, Landsat 8, GTOPO-30, SRTM-30, SRTM-1, SRTM-3, ASTER. For the test area the island of Cyprus was chosen because of the importance in tourism, a relatively small area and a clearly defined boundary. In the paper there are shown and discussed various options of the Cyprus terrain image obtained synthetically from variants of Modis, Landsat and digital elevation models of different resolutions.
Moscicka A.,Institute of Geodesy and Cartography
International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM | Year: 2013
In the paper, the movable monuments integration in one space with the use of GIS technology is proposed. From the user's point of view, GIS is a tool that very strongly supports the dissemination and promotion of cultural heritage resources. Above all, the GIS provides access to resources - regardless of their original location - from one common level, from the map. However, there is a lack of GIS collecting the number of resources from more than one institution. The reason for the current situation are perhaps the differences in the ways of collecting the collections, describing them and way of digitization. Created databases are different, the exchange of data between them requires advanced computer knowledge, and often it is completely impossible. The subject of using monuments descriptions - prepared with the use of international standards - as a basis for movable collections integration, is described in the paper. Standards for description immovable heritage, as well as standards used in digital libraries are taken into consideration. The aim of the work is the possibility of creating one common spatial databases for monuments. The most popular standards of monuments descriptions were analyzed. The scope of the information collected and their semantics, and above all the importance and way o saving and integrating spatial information are described. © SGEM2013 All Rights Reserved by the International Multidisciplinary Scientific GeoConference SGEM.
Linsenbarth A.J.,Institute of Geodesy and Cartography
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives | Year: 2010
The paper presents the concept of a spatio-temporal geoinformation system of the Bible events. In 2006 in the Institute of Geodesy and Cartography in Warsaw, the research project dealing with the concept of a complex time related spatial information system was undertaken. The main goal of this project was to create a spatio-temporal system, which allows to connect the Bible contents, namely the geographical objects indicated in the Bible with the geospace, presented on various geographic and Bible thematic maps. The proposed spatio-temporal system consists of three databases: the reference maps database, the geographic objects database and the thematic database. The reference maps database consists of DTM and vector maps in three scales: 1:20 000 000, 1:1 000 000 and 1:200 000 depending on the extent of the mapped territory. The most up-to-date topographical maps in various scales, as well as, the satellite images and the digitalal terrain models (DTM) were used for compilation of reference maps. In the geographic object database the list of all geographical objects occurring in the Bible is located. For all objects the status of the degree of their identification in the geospace is given. The changes of names of the geographical objects within the various periods of history are introduced to the database. Also a brief description of each object is added. In the geographic object database the list of all geographical objects occurring in the Bible is located. For each one geographic name its appearance in the Bible text is indicated. Also the brief description of each object is added. In the thematic database, the Bible events are listed in chronological order and described in accordance with the Bible texts and non Bible sources. Due to the interaction of the information incorporated in these databases, the reader of the Bible, has a connection with the proper maps and location of the geographic object and has an access to the additional information regarding accuracy of identification, appearance of the name of this object in all chapters in the Bible and description of this object in the various periods of history.
Agata H.,Institute of Geodesy and Cartography |
Aneta L.,Institute of Geodesy and Cartography
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2015
The Earth Observation data are recognized as valuable source of information about fire events. In this paper we present the potential of using the satellite-based 'hotspots' in management of fires as well as challenges of validating the remotely detected fire events in Poland. We compare the spatio-temporal distribution of fires derived from satellites against ground-based fires reported in the National Forest Fire Information System. The preliminary results showed that about 35% of the remotely detected fires were recorded in the ground-based fire database over the period 2002-2013. The satellites has missed the vast majority of vegetation fires. The limitation of both databases was also discussed. The analysis of fire intensity, for the fires detected both remotely and on the ground, demonstrated that forest fires were the greatest and the most intensive fires. However, the analysis of the mean Fire Radiative Power values calculated for all recorded MODIS hotspots confirmed that wetland fires are the most intensive considering that the number of burning events was relatively low. © 2015 IEEE.