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Accuracy of Location Identification by GPS and Possibilities for its Application in Agriculture
Published May 4, 2004

A description of the design and operating principle of the GPS system and the explanation of key terms of telemetric and chronometric measurements is followed by several examples characteristic of the results of factors which may influence accuracy of the identification of geographic location by satellites. In addition, results of accuracy of absolute GPS measurements and improvements of accuracy experienced and attributable to the alteration of the periods used for establishing average values are highlighted. Furthermore, we examined certain practical possibilities for the use of GPS systems in agriculture, emphasizing the advantages hidden in the use of GIS-GPS integration, crop mapping, soil maps and gross produce maps, in the application of the VRT (Variable Rate Technology) and in combinations of the same.

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Spatially Discrete GIS Analysis of Sampling Points Based on Yield and Quality Analysis of Sugar Beet (Beta vulgaris L.)
Published March 4, 2006

Fulfilment of the increasing quality requirements of sugar beet production can be analysed with sampling of plants and soil at the cultivated area. Analyses of the spatial characteristics of samples require exact geodetic positioning. This is applied in practice using GPS in precision agriculture. The examinations were made in a sample area loc...ated in north-western Hungary with sugar beet test plant. According to the traditional sample taking procedure N=60 samples were taken in regular 20 x 20 m grid, where besides the plant micro and macro elements, the sugar industrial quality parameters (Equations 1-2) and the agro-chemical parameters of soils were analysed. Till now, to gain values of mean, weighted mean and standard variance values, geometric analogues used in geography were adapted, which correspond to the mean centre (Equation 3), the spatially weighted mean centre (Equation 4), the standard distance (Equation 5), and the standard distance circle values. Robust spatial statistical values provide abstractions, which can be visually estimated immediately, and applied to analyse several parameters in parallel or in time series (Figure 1). This interpretation technique considers the spatial position of each point to another individually (distance and direction), and the value of the plant and soil parameters. Mapping the sample area in GIS environment, the coordinates of the spatially weighted mean centre values of the measured plant and soil parameters correlated to the mean centre values showed a northwest direction. Exceptions were the total salt and calcium-carbonate contents, and the molybdenum concentration of the soil samples (Table 1). As a new visual analysis, the spatially weighted mean centre values of the parameters as eigenvectors were projected to the mean centre values as origin. To characterize the production yield, the raw and digested sugar contents of the sample area, the absolute rotation angles of the generated vectors were determined, which indicate numerically the inhomogenity of the area (Figure 2). The generated spatial analogues are applicable to characterise visually and quantitatively the spatial positions of sampling points and the measured parameters in a quick way. However, their disadvantage is that they do not provide information on the tightness and direction of the spatial correlation similarly to the original statistical parameters.

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Applicability of hyperspectral technology for in situ phytoremediation
Published October 10, 2008

The characterization of heavy metal polluted abandoned mining sites is a complicated assignment due to the variable spatial distribution of the pollutants, therefore complex integrated method is required in order to assess precisely the amount and the distribution of the contaminants. The examined area is flotation sludge reservoir of abandoned... Pb-Zn mining site with serious heavy metal contamination. located in Gyöngyösoroszi, Northern Hungary.
The hyperspectral image of the flotation sludge is obtained by using a Digital Airborne Imaging Spectrometer DAIS 7915, in the frame of DLR HySens first Hungarian hyperspectral flight campaign (21/08/2002). Parallel to the flight campaign heavy metal content of soil samples were examined from the area of the flotation sludge. The analysis of hyperspectral data was verified by the examination of mine tailing samples by FPXRF (Field Portable X-ray Fluorescence spectrometry) (NITON XL-703).
Determinations of heavy metal containing minerals are based on the spectral profiles of the pixels of the area with using USGIS standard spectral profiles of the examined materials (galena, pyrite, sphalerite, goethite and jarosit).

Applying the Spectral Angle Mapper with BandMax classification the distribution of minerals (galena, pyrite, sphalerite, goethite, jarosit) in the area was defined. The mineral formation occurs especially at the levees and the barren places of the Szárazvölgyi flotation sludge reservoir. Based on the statistic results of the samples, principal component analysis and correlation coefficient between the different metal content of the samples were calculated. The highest correlations were found between Pb-Zn, Fe-Zn and between Fe-Pb. This prove the results of the principal component analysis, where usually Pb, Zn, Fe introduce the main component.

Canopy analysis was also carried out with the hyperspectal image in order to classify the differences between vegetation types at the Szárazvölgy flotation sludge reservoir and analyse the applicability of it. Supervised classification methods were used to distinguish 8 vegetation types based on the spectral properties of the area. The results of the classifications were compared to a ground truth image, based on ortophoto, topographic map, and GPS based field data collection. According to results of the comparison, the paralellpiped classification method is proved to be appropriate method based on the overall accuracy of canopy classification, which was 54% due to heterogeneity of the vegetation. 

The results of hyperspectral data and FPXRF analysis suggest that Pb, Zn and Fe containing minerals have similar spatial distribution in the examined and barren area.

Based on this study hyperspectral remote sensing is likely to be an effective tool for the characterization and modeling the distribution of Pb, Zn and Fe containing minerals at the examined heavy metal polluted sites. Further more, based on the vegetation analysis plant species for phytoremediation can be defined.

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Challenges and limtations of site specific crop production applications of wheat and maize
Published November 13, 2012

The development and implementation of precision agriculture or site-specific farming has been made possible by combining the Global Positioning System (GPS) and the Geographic Information Systems (GIS). Site specific agronomic applications are of high importance concerning the efficiency of management in crop production as well as the protectio...n and maintenance of environment and nature. Precision crop production management techniques were applied at four locations to evaluate their impact on small plot units sown by wheat (Triticum aestivum L.) and maize (Zea mays L.) in a Hungarian national case study. The results obtained suggest the applicability of the site specific management techniques, however the crops studied responded in a different way concerning the impact of applications. Maize had a stronger response regarding grain yield and weed canopy. Wheat was responding better than maize concerning plant density and protein content performance.

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Development of precision apple production technologies in Institute of Water and Environmental Management
Published July 18, 2012

From the precision agriculture point of view, by the rapid development of the investigated technological elements – global positioning system (GPS), remote sensing (RS), global information system (GIS) – the number of services, which were not available in the past, because of their speed, complexity or price are increasing. The high accurac...y high-tech instruments provide opportunity to elaborate several fruit production technologies, which aim is creating and operating water and energy safe quality fruit production systems. To evaluate these possibilities, experience was carried out in the Study and Regional Research Farm of the University of Debrecen near Pallag with the use of a GreenSeeker 505 Hand Held™ Optical Sensor Unit, and its interface the Trimble AgGPS FmX Integrated Display board computer, and a ScanStation C10 laser scanner by Leica. The results show the absolute applicability of these equipments in precision horticulture.

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The management and economical aspects of GPS based machine-control and tractor-implement sincronisation
Published March 20, 2013

...5); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">Precision farming has an array of technological equipment, elements and complete systems which are in themselves suitable to create conditions for efficient farming, to reduce environmental load and to provide farmers with optimal return on their investment.

On the leading edge of my research is to introduce the economic benefits of precision logistic optimization with satellite navigation in wheat and maize harvesting. My hypothesis, claiming that a well-organized system can increase the number of working days by 4 days per harvesting season in maize, and 2 days in wheat crop. If the farmer makes contract works for harvesting it means for him 2 or 4 days extra work by using the precision farming technologies with satellite communication system. Overall, as pertains to wheat and maize harvest seasons, yearly revenues can be increased by 7 760 000 HUF. I would like to introduce that the precision technologies increase combine costs by merely 5.4% which can be return in the first year of using.

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Virtual Soil Information Systems in the Bihar Subregion and at Tedej Corp
Published May 4, 2004

After evaluating the sample sites’ soils and environmental status, we built up 2 different soil information systems. The first relies on analog data (soil maps), and is based on a regional model; its sample site is the Bihar sub-region. The second is a complex, field scale virtual 3D system, based on several types of data sources. (Aerial pho...tos, GPS, field samples, hyper and multispectral images, soil maps). In this paper, we analyze and evaluate these systems. The greatest advantage of the models is that, with their usage, we can reveal connections which cannot be made by analyzing the individual elements of our data sources. We discovered that with the help of our systems, the monitoring and evaluating of the processes taking place in the soil is more fast and simple.

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Development opportunities for storing and displaying of spatial data in long-term experiments
Published February 18, 2016

Long-term experiments are required to evaluate the impact of irrigation, nutrient utilization, and year factor as well as to assess the potential consequences of climate change. However, in the long-term experiment, it may be necessary to display spatial data for each parcel, either for investigation of soil heterogeneity or presentation. This ...article aims to provide help for researchers working in long-term experiments for storing and displaying spatial data.

After the outlines of each experimental site were measured with GPS, a spatial database has been created in Quantum GIS. Then, a filter script in R statistical environment using RStudio graphical interface was written. The script helps avoid the QGIS data input interface so that large data can be attached to each parcel directly and as a result there is no need for a separate data entry, only the basic statistical database.

The created GIS database can be used in many ways; it can be exported to KML file format that can be displayed using Google Earth. It is possible to view exported KML files in Google Drive with importing them to Google My Maps application, and with that a browser can display the map. With the Google Drive the maps can be shared within the research group, additionally the outlines can be edited and it is possible to upload the measurement data to the attributes table to existing empty table columns. The map created in Quantum GIS can be used for presentation purposes.

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