Papers by Giorgos Papadavid
IOS Press, 2010
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ABSTRACT Remote sensing techniques development have provided the opportunity for optimizing yield... more ABSTRACT Remote sensing techniques development have provided the opportunity for optimizing yields in the agricultural procedure and moreover to predict the forthcoming yield. Yield prediction plays a vital role in Agricultural Policy and provides useful data to policy makers. In this context, crop and soil parameters along with NDVI index which are valuable sources of information have been elaborated statistically to test if a) Durum wheat yield can be predicted and b) when is the actual time-window to predict the yield in the district of Paphos, where Durum wheat is the basic cultivation and supports the rural economy of the area. 15 plots cultivated with Durum wheat from the Agricultural Research Institute of Cyprus for research purposes, in the area of interest, have been under observation for three years to derive the necessary data. Statistical and remote sensing techniques were then applied to derive and map a model that can predict yield of Durum wheat in this area. Indeed the semi-empirical model developed for this purpose, with very high correlation coefficient R2=0.886, has shown in practice that can predict yields very good. Students T test has revealed that predicted values and real values of yield have no statistically significant difference. The developed model can and will be further elaborated with more parameters and applied for other crops in the near future.
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... Anthony Morse Idaho Department of Water Resources Dr. Richard G. Allen University of Idaho Ma... more ... Anthony Morse Idaho Department of Water Resources Dr. Richard G. Allen University of Idaho Masahiro Tasumi University of Idaho William J. Kramber Idaho Department of Water ResourcesRicardo Trezza University of Idaho Dr. James L. Wright USDA-ARS Page 2. ...
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Fifth International Conference on Remote Sensing and Geoinformation of the Environment (RSCy2017), 2017
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Second International Conference on Remote Sensing and Geoinformation of the Environment (RSCy2014), 2014
Agricultural robots can tackle harsh working conditions and hardness of work, as well as the shor... more Agricultural robots can tackle harsh working conditions and hardness of work, as well as the shortage of laborers that is a bottleneck to agricultural production. Such robots exist, but they are not yet widespread. We believe that the limited usage of robotics in agriculture could be related to the fact that the mainstream direction for robotics in agriculture is full automation. The teleoperation of an agricultural robotic system can enable improved performance overcoming the complexity that current autonomous robots face due to the dynamic and unstructured agricultural environment. A field study was conducted to evaluate eight different user interfaces aiming to determine the factors that should be taken into consideration by designers while developing user interfaces for robot teleoperation in agriculture. Thirty participants, including farmers and agricultural engineers, were asked to use different teleoperation interaction modes in order to navigate the robot along vineyard rows and spray grape clusters. Based on our findings, additional views for target identification and peripheral vision improved both robot navigation (fewer collisions) and target identification (sprayed grape clusters). In this paper, we discuss aspects of user interface design related to remote operation of an agricultural robot.
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ABSTRACT Field spectroscopy is a part of the remote sensing techniques and very important for stu... more ABSTRACT Field spectroscopy is a part of the remote sensing techniques and very important for studies in agriculture. A GER-1500 field spectro-radiometer was used in this study in order to retrieve the necessary spectrum data of the spring potatoes for estimating spectral vegetation indices (SVI's). A field campaign was undertaken from September to the end of November 2012 for the collection of spectro-radiometric measurements. The study area was in the Mandria Village in Paphos district in Cyprus. This paper demonstrates how crop canopy factors can be statistically related to remotely sensed data, namely vegetation indices. The paper is a part of an EU cofounded project regarding estimating crop water requirements using remote sensing techniques and informing the farmers through 3G smart telephony.
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Central European Journal of Geosciences, 2013
In this paper, Leaf Area Index (LAI) and Crop Height (CH) are modeled to the most known spectral ... more In this paper, Leaf Area Index (LAI) and Crop Height (CH) are modeled to the most known spectral vegetation index — NDVI — using remotely sensed data. This approach has advantages compared to the classic approaches based on a theoretical background. A GER-1500 field spectro-radiometer was used in this study in order to retrieve the necessary spectrum data for estimating a spectral vegetation index (NDVI), for establishing a semiempirical relationship between black-eyed beans’ canopy factors and remotely sensed data. Such semi-empirical models can be used then for agricultural and environmental studies. A field campaign was undertaken with measurements of LAI and CH using the Sun-Scan canopy analyzer, acquired simultaneously with the spectroradiometric (GER1500) measurements between May and June of 2010. Field spectroscopy and remotely sensed imagery have been combined and used in order to retrieve and validate the results of this study. The results showed that there are strong stati...
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Seventh International Conference on Remote Sensing and Geoinformation of the Environment (RSCy2019), Aug 1, 2013
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Fifth International Conference on Remote Sensing and Geoinformation of the Environment (RSCy2017), Sep 6, 2017
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ABSTRACT This paper describes the results obtained by the direct comparison between the visibilit... more ABSTRACT This paper describes the results obtained by the direct comparison between the visibility values obtained from satellite remotely sensed data and ground measurements in an area of interest near the Paphos International Airport in Cyprus. During the satellite overpasses, visibility values are obtained from the nearby airport and sun-photometer measurements are acquired using the MICROTOPS II sun-photometer. It has been found from previous studies that there is direct relationship between the aerosol optical thickness and the visibility values so the use of sun-photometer is an essential tool for ground validations. Water vapor measurements have also compared between the relative humidity (RH) measurements monitored in the airport and those measured in-situ using the sun-photometer. It has been found that visibility values is strongly related with the aerosol and water vapor concentrations and this can be taken into consideration when satellite remote sensing is used for meteorological and environmental monitoring applications. Considering that the monitoring of aerosol concentrations becomes a high environmental priority particularly in urban area, this study explores the direct relationship between the aerosol optical thickness and visibility and highlights the importance of further validations.
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The chapter presents an overview of various methods and model approaches that can be used to deri... more The chapter presents an overview of various methods and model approaches that can be used to derive crop evapotranspiration and agricultural yield state from remote sensing data. The overview is based on an extensive literature review. The studied literature reveals that many valuable techniques have been developed both for the retrieval of evapotranspiration and crop yield from reflective remote sensing data as for the integration of the retrieved variables into crop models. However, for crop modelling and remote sensing data assimilation to be commonly employed on a global operational basis, emphasis will have to be put on bridging the mismatch between data availability and accuracy on one hand, and model and user requirements on the other. This could be achieved by the integration of images with different spatial, temporal, spectral and angular resolutions, and the fusion of optical data with data from different sources.
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IGARSS 2019 - 2019 IEEE International Geoscience and Remote Sensing Symposium, 2019
This paper aims to explore the integration of field spectroscopy and satellite remote sensing app... more This paper aims to explore the integration of field spectroscopy and satellite remote sensing approaches to detect underground structures in Cyprus. A SVC-HR1024 field spectroradiometer was used and in-band reflectances were determined for medium resolution Landsat 7 ETM satellite sensor. In order to study possible differences of the spectral signature of vegetation, Normalized Difference Vegetation Index (NDVI), Simple Ratio (SR) and Enhanced Vegetation Index (EVI) have been used for the detection of underground military structures. The simulation results show that Vegetation Indices are highly useful and extremely valuable for detection underground infrastructures in Cyprus. In this study, two test areas were identified, analyzed and modelled: Area (a) which is a Vegetation Area covered with vegetation (barley), in the presence of an underground military structure, and Area (b) which is a Vegetation Area covered with vegetation (barley), in the absence of an underground military s...
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The PoPaTERVA project is developing applied research regarding the comprehension of the multi-lay... more The PoPaTERVA project is developing applied research regarding the comprehension of the multi-layered cultural background of the Terva Valley Archaeological Park, in Boticas, Portugal. One of the main aspects focused on the project is the appliance of remote sensing techniques to enhance non visible archaeological features. An earth resistance tomography (ERT) survey was carried out at the Sapelos hillfort, by the specialized SINERGEO geophysicist’s team, using a Wenner-Schlumberger array. The resulting data was analyzed by the authors in order to extract and verify valid archaeological features regarding the settlement’s structures. There are several adequate systems that can be used to visualize the surveyed data (x, y, z, Ω). However, the authors preferred the open source Visualization Toolkit (VTK) from Kitware Inc., since it supports several visualization and modelling techniques that are useful for interpretation purposes in archaeological contexts: for instance, it is possibl...
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The imperative need for data on irrigation management in Cyprushas led to a turnoff regarding the... more The imperative need for data on irrigation management in Cyprushas led to a turnoff regarding the method of collecting and analyzing irrigation management primary data. The time and money consuming direct measurements of evapotranspiration (ETc), such as Pan-evaporation methods, lysimeters and others, are substituted from efficient energy and hydrological models which are adapted to satellite data. Remote sensing methods are attractive to estimate ET as they cover large areas and can provide estimates at a very high resolution. Intensive field monitoring is also not required, although some ground-truth measurements can be helpful in interpreting the satellite images. More specific, for the purposes of this paper, modeling and remote sensing techniques were integrated for estimating actual evapotranspiration (ET a ) for a local cultivation (groundnut – Arachis hypogaea , L.), that is cultivated only at the specific area of interest. Data for irrigation management exist for the specif...
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ABSTRACT Bearing in mind that the atmospheric effects are mainly caused by scattering and absorpt... more ABSTRACT Bearing in mind that the atmospheric effects are mainly caused by scattering and absorption of atmospheric gases, aerosol and clouds, the most important point in order to perform an atmospheric correction is to be aware of the optical characteristics of the atmosphere. These optical characteristics can be found from different sources such as the general climatology of the area under investigation or ground measurements. Molecular scattering and absorption are not considered to vary in time and space. Nevertheless, aerosol scattering and absorption do vary and these are the main variables in the atmospheric effect on satellite remote sensing. One way to describe the information which refers to the atmospheric optical characteristics is by using the sun-photometer to measure directly the aerosol optical thickness and the water vapor concentrations. Based on the fact that for the hydrological applications, time-series image data acquired over time are required, the fundamental objective of applying the atmospheric correction is to retrieve the true spectral signatures of the land-cover prior to their use in any hydrological models. The atmospheric correction is performed by using the normalization method using standard calibration targets. For assessing the performance of such atmospheric correction, during the satellite overpass reflectance measurements of different targets areas such as soil, vegetation, asphalt area, sea-water have been acquired using the GER1500 and SCVHR-1024 field spectroradiometers. Microtops II sun photometer has been used to measure the aerosol, water vapor and ozone thickness during the Landsat TM/ETM and MODIS satellite overpasses. Thearea under investigation was Paphos District area in Cyprus. An agricultural area irrigated by the Asprokremmos Dam has been selected. It has been found that is important to take account of atmospheric effects for both single date and time-series satellite imagery in hydrological studies in which several spectral targets are appeared.
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Earth Resources and Environmental Remote Sensing/GIS Applications VI
This paper focuses on the use of Unmanned Aerial Vehicles (UAVs) over the study area of Pissouri ... more This paper focuses on the use of Unmanned Aerial Vehicles (UAVs) over the study area of Pissouri in Cyprus to document the sloping landscapes of the area. The study area has been affected by overgrazing, which has led to shifts in the vegetation patterns and changing microtopography of the soil. The UAV images were used to generate digital elevation models (DEMs) to examine the changes in microtopography. Next to that orthophotos were used to detect changes in vegetation patterns. The combined data of the digital elevation models and the orthophotos will be used to detect the occurrence of catastrophic shifts and mechanisms for desertification in the study area due to overgrazing. This study is part of the "CASCADE- Catastrophic shifts in dryland" project.
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Fourth International Conference on Remote Sensing and Geoinformation of the Environment (RSCy2016), 2016
Water allocation to crops, and especially to the most water intensive ones, has always been of gr... more Water allocation to crops, and especially to the most water intensive ones, has always been of great importance in agricultural process. Deficit or excess water irrigation quantities could create either crop health related problems or water over-consumption situation which lead to stored water reduction and toxic material depletion to deeper ground layers, respectively. In this context, and under the current conditions, where Cyprus is facing effects of climate changes, purpose of this study is basically to estimate the needed crop water requirements of the past (1995-2004) and the corresponding ones of the present (2005-2015) in order to test if there were any significant changes regarding the crop water requirements of the most water intensive trees in Cyprus. Mediterranean region has been identified as the region that will suffer the most from climate change. Thus the paper refers to effects of climate changes on crop evapotranspiration (ETc) using remotely sensed data from Landsat TM/ ETM+ / OLI employing a sound methodology used worldwide, the Surface Energy Balance Algorithm for Land (SEBAL). Though the general feeling is that of changes on climate will consequently affect ETc, the results have indicated that there is no significant effect of climate change on crop evapotranspiration, despite the fact that some climatic factors have changed. Applying Student’s T-test, the mean values for the most water intensive trees in Cyprus of the 1994-2004 decade have shown no statistical difference from the mean values of 2005-2015 decade’s for all the cases, concluding that the climate change taking place the last decades in Cyprus have either not affected the crop evapotranspiration or the crops have manage to adapt into the new environmental conditions through time.
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Papers by Giorgos Papadavid