Remote Sensing

Para realizar o download do Legado Landsat no “site da NASA”, o local da Web formalmente conhecido como Serviço Geológico dos Estados Unidos (U.S.G.S. – United States of Geological Survey), é necessário preencher um formulário de cadastro bem detalhado, porém fundamental para o aperfeiçoamento dos produtos que o portal oferece para a comunidade global.

Pelo menos uma vez ao mês eu visito o site USGS para ter acesso à família Landsat e outros produtos. Os mecanismos para pesquisa de imagens são práticos e intuitivos. Algumas funcionalidades foram abordadas de forma suave através deste tutorial. Um fato que chama atenção no site é o registro obrigatório: para ter acesso ao produto completo para download, o usuário precisa estar cadastrado e logado no site.

The present study demonstrates the potential of the geospatial information as well as isotopes and chemical analyses to elucidate the hydrogeological setting of the study area. The main objective of this research is to identify factors affecting the occurrence and quality of
groundwater in the study area. The Ras Alam El Rum is the pilot area chosen in the northwestern coast of Egypt to evaluate the carbonate aquifer with emphasis on the Middle Miocene aquifer, which has been explored recently. The average of annual precipitation and surface runoff amounts were estimated to indicate possibility of groundwater recharge, where the water-bearing rocks are mainly fractured. The isotope data indicate that the groundwater was derived from rainwater, the recharge source is local precipitation, and no indication of seawater intrusion was recorded. The salinity of the groundwater is attributed to interaction between the water and aquifer rocks represented by limestone, dolomitic limestone, and marl. The mineral indices obtained from the geochemical model reveal that the groundwater is oversaturated with aragonite, calcite, dolomite, strontianite, and barite. The hydrogeological evaluation of the study area led to recommendations to determine of the suitable areas for
exploration of the Middle Miocene aquifer and to protect groundwater from deterioration.

Abstract The northwestern coast of Egypt represents one
of the highest-priority regions for future development.
Two contiguous basins were chosen from the northwestern
coast for this research: El Zarraqa and El Harraqa
basins. The main objective of the present study is to
provide geomorphologic and geological data in order to
work on the water potentiality development in the study
area. The obtained data through the present study reveal
that, although the two studied basins are close to each
other, they are not compatible with all features. The
morphometric parameters reveal that the studied basins
have opportunities for surface runoff occurrence and also
for groundwater recharge through infiltration process. The
geology of the study area is dominated by sedimentary
rocks of Tertiary and Quaternary ages. The study area has
favorable conditions for groundwater accumulation,
where this area receives an average annual precipitation
of 151.95 mm, which provides the opportunity for
groundwater recharge. The hydrogeological investigations
reflect that two groundwater aquifers (Middle Miocene
and Pleistocene) are recorded in the El Harraqa basin,
and only the Middle Miocene aquifer is recorded in the
El Zarraqa basin. The Middle Miocene aquifer needs more
hydrogeophysical investigations to explore its potentialities
where its rocks have a wide distribution and are
mainly fractured. The difference in groundwater salinity
in both aquifers accompanied by different hydrogeologic
data confirms that the carbonate aquifer in the studied
basins is heterogeneous and has anisotropic characters.
The current research set up a proposed plan which includes
multiactivities for the protection and development
of the water resources.

      Gully erosion mapping is a crucial step to monitor the erosion process and to study its current and future local impacts. In arid environments such as Fars Province of Iran, gullies extend over a vast area and accurate field mapping is difficult, time-consuming and costly. The research reported in this paper compares various pixel-based image classification (PBC) algorithms such as ISODATA, MLC and SVM with the object-based image analysis (OBIA) technique for gully erosion mapping on IRS-P6 images. Six models defined by classification types, classifiers and feature spaces were built for comparison. The results show that OBIA classification performed better than PBC in terms of accuracy. We also found that the improvement of OBIA was primarily due to employing textural and shape features and optimized feature space (OFS), while the use of standard feature space (SFS) did not improve OBIA. In addition, OBIA significantly reduced the salt and pepper effect that obscure the features on the output maps compared to the PBC maps with more salt and pepper effects. It seems object-based techniques have gained a better results because of their focus on shape of Gully networks more than their spectral heterogeneity. In order to improve the accuracy, a priority may be gained by fully exploring the use of membership function and hierarchical approach with multi-scale segmentation for gully erosion mapping. In future studies, we propose to determine how these factors can affect the performance of OBIA for gully mapping. This study provides information on the location of gullies, gully dynamics over a period of time and the degree of land degradation (gully density) for developing and implementing soil conservation measures.

Gully erosion is a serious problem at many locations worldwide, but little is known about its importance at large spatial scales. Recognizing the regions affected by critical soil erosion reveals priorities for soil conservation. Improving gully mapping methods by applying remote sensing is important and beneficial for erosion control, around the world. One of applicable approachs of mapping soil erosion by using remote sensing techniques is through the use of the powerful capabilities of supervised classification algorithms. The complex nature of gully erosion and its surrounding areas also confirmed to be challenging for gully mapping by use of conventional pixel-based classifiers.This study was conducted to determine which one pixel-based classification methods of remote sensing such as SVM and MLC could accurately determine the gully erosion. In the present research it is tried, to determine superior technique among remote sensing gully mapping thechniques. Hence pixel- based (MLC and SVM) classification Methods applied to IRS (p6 sensor) LISSIII imagery and gully maps were created. Mapping of gullies using classification algorithms highlighted the spectral complexity of gullies and the challenges faced when trying to identify them from the surrounding areas. Analysis of the pixel-based classification methods shown that Support vector machine (SVM), mapped gullies more accurate (kappa=0.63) than MLC (kappa=0.54) and was the recommended approach to gully mapping using remote sensing in this case study. This is because SVM is non parametric and only uses the support vectors which lie in the region where the classes meet and not the whole training data set. Thus SVM maximizes on the complexity of the classes at the boundary and is unaffected by the within class variance.

Remote-sensing, archaeological field survey and GIS are combined by the Finnish Project SYGIS in the studies of the Euphrates valley confined by the mountain of Jebel Bishri in Central Syria. Changes in the course of the river channel have caused transformations in the occupational past and landscape. The alluvial terraces offer evidence of the earliest human impact from the Lower Palaeolithic period. Several tells, ancient mounds of towns or villages, have been identified, surveyed and mapped in the region. Our aim is to study short-term variations of the river channel with satellite images in order to trace some scales and tempo of the channel changes that may also have affected the past occupation. Our aim is to find out, how the acquired information can becombined for the purpose of interpreting the archaeological evidence of the past occupation, even the landscape of historical events in the area. Satellite images used in this study consists of declassified CORONA satellite photographs from 1966, Landsat MSS (1983), Landsat TM (1990) and ETM (1999 and 2001) images. SPOT images covering the research area are used for mapping tells and for evidence of the present situation of the river valley. The interpretation of the water areas is based on the cluster analysis and visual interpretation. The topographic variations of the river channel are visualized using colour coding of DEMs and plots of the cross sections of the river channel. An Aster image from USGS has been used to produce DEM in order to study the cross-section of the river valley.

Nowadays we can travel by GoogleEarth 3D to Syria (http://www.worldcountries.info/GoogleEarth/GoogleEarth-Syria.php) and zoom in on the desert landscape of the mountainous region of Jebel Bishri between the Euphrates river and the Syrian Desert. This is the area, where the Finnish archaeological survey and mapping project SYGIS worked in 2000-2010 studying the relationship of humans with their environment from ancient times to the present. What kind of landscape views and visions did the ancients have and how did they utilize them? The present paper focuses on seeking answers for these questions by combining satellite data sources, such as imagery and radar data, with location information of archaeological remains collected on the ground. Landsat as well as QuickBird imagery have been fused with SRTM mission and ASTER DEM data in creating 3D landscape models and fly-over simulations. The oasis of El Kowm on the western piedmont of the mountain seems to have served as a base camp for early hunter-gatherers and pastoral nomads dwelling seasonally in the region of Jebel Bishri. According to the archaeological finds, the interaction between the lowland and the mountain people already started during the Palaeolithic era but was continued by pastoral nomads of the region from the Neolithic period onwards. The Upper Palaeolithic period meant a clear change in cognitive thinking and obviously in understanding the properties of landscape, visibility and perceiving sceneries in 3D. Mobility of hunter-gatherers and pastoral nomads is based on subsistence economy, but mobility also enhances visions and prospects of phenomena appearing in the horizon.

Proceedings of the 6th International Congress on the Archaeology of the Ancient Near East, May, 5th-10th 2008, “Sapienza” - Università di Roma, Volume 1, Near Eastern Archaeology in the Past, Present and Future. Heritage and Identity, Ethnoarchaeological and Interdisciplinary Approach, Results and Perspectives, Visual Expression and Craft Production in the Definition of Social Relations and Status. Edited by Paolo Matthiae, Frances Pinnock, Lorenzo Nigro and Nicolò Marchetti with the collaboration of Licia Romano. 2010. Harrassowitz Verlag. Wiesbaden, pp. 369-390.

Climate change and its impact on nomadic life can be scrutinized from a long term perspective at Jebel Bishri belonging to the Palmyride mountain belt in Syria. The area has been a nomadic habitat for millennia. A satellite image perspective provides information about desertification and its pace in modern times in the region. Ethnoarchaeology in this vulnerable area opens a loop to possible past choices that nomadic people have had during environmental hazards. The movement of the desertification line can nowadays be monitored by Landsat satellite images covering several decades, and the relationship of the line to the shifting cultivation of Bedouins can be studied. The ethnoarchaeological study of the Bedouin life and the living compounds in the region reveals the dynamics leading to sedentarization vis-à-vis site abandonment processes. The impact of availability of water and periods of droughts on this life cycle are analysed taking into account the socio-political situations. Implications of the results of these ethnoarchaeological studies are discussed in the light of the archaeological evidence and the past situations in the region.

The early-medieval Netherlands witnessed major changes in
landscape, economy, demography and also possibly climate.
Archaeological evidence throughout north-western Europe, including
the Netherlands, indicates severe demographic decline
and changing settlement patterns in the late-Roman and post-
Roman periods. To what extent the inhabitants of the earlymedieval
Lowlands adapted to the increasingly changing landndscapes
and how this is reflected in large-scale patterns is generally
unknown. Historical route networks provide a key to -
understanding large-scale settlement patterns as well as demography
and land use.

A field experiment was carried out during rabi 2010-11 and 2011-12 to study the canopy reflectance and to predict the grain and biomass yield of wheat (Triticum aestivum L.) under different irrigation and nitrogen management practices using canopy reflectance spectra model. Wheat (cv. PBW 502) was grown with four levels of irrigation, i.e. 0.4, 0.6, 0.8 and 1.0 IW/CPE and three N sources, i e 120 kg N/ha as urea, 60 kg N/ha as urea + 60 kg N/ha as farmyard manure (FYM) and 120 kg N/ha as FYM. Three spectral reflectance indices, viz. Red Normalized Difference Vegetation Index (RNDVI), Green Normalized Difference Vegetation Index (GNDVI) and Simple Ratio (SR) were computed using the spectral reflectance data. It was observed that across the treatments, the RNDVI, GNDVI, and SR increased from crown root initiation (CRI) to booting stage and thereafter decreased progressively till harvest. The pooled yield data of both the years showed significantly higher yield in 0.8 and 1.0 IW/CPE irrigation levels than 0.4 and 0.6 IW/CPE irrigation levels. The pooled data of grain yield under different nitrogen practices showed significantly higher yield in urea treatment followed by urea+FYM treatment and FYM treatment. The biomass yield under different nitrogen management practices followed trend similar to grain yield. A significant and positive correlation coefficient was observed between grain and biomass yield and spectral reflectance indices (RNDVI, GNDVI, SR) for all the phenological stages except at CRI stage and maturity stage. Highest correlation coefficient (0.97 for grain yield and 0.93 for biomass yield) was observed for GNDVI measured at milking stage. The model could account for 79 % variation in the grain yield of wheat with root mean square error (RMSE) (%) of 17.1. Similarly the model could account for 86% variation in the biomass yield of wheat with RMSE (%) of 12.7. The models slightly underestimate the grain and biomass yield of wheat with coefficient of residual mass (CRM) value of 0.13 and 0.08, respectively.

Use of rainfall anomaly based Standardized Precipitation Index (SPI) and satellite-derived Vegetation Condition Index (VCI) are becoming common to assess the impacts of drought on crops. This study analyzed spatio-temporal intra-seasonal and inter-seasonal relationships for 24 years between rainfall and NDVI and between SPI and VCI to understand crop response to water availability in the Rajasthan State, India. To separate the effect of weather and technology on crop growth over time, a modification in VCI was proposed and called "Trend Adjusted VCI" (VCITadj). The VCITadj was computed for early, mid, late and whole crop seasons by deriving pixel wise crop phenology metrics from NDVI profile. Significant linear relationships were found between NDVI and rainfall but phase of crop season affected the strength of this relationship. The SPI and VCITadj were linearly related in all the four seasons, the strength of relationship improved with the progress of crop season and these relationships were stronger than between rainfall and NDVI. These relationships broke down in irrigated croplands. As a result, the anomaly indices of SPI and VCITadj and their intra-seasonal relationships can be used to study the response of crops to water availability for early detection and better prognosis of agricultural drought.

The presence of high resolution satellite images and their potentials to be used in many fields such as urban planning, transportation engineering etc ,especially in the meaning of preparing and updating maps, have made the automatic extraction of objects, a new challenge in remote sensing. Automatic road extraction, one of major uses of preparing and updating maps, provides means for creating, maintaining, and updating transportation network, which subsequently offers databases for all means of traffic management. Moreover, automatic road extraction is a critical feature for an efficient use of remote sensing imagery in most contexts, which has been an active research area in computer vision and digital photogrammetric for over past decades.
Further, the pixel-oriented analysis of satellite data has a main limit: the acknowledgement of semantic low level information, as the amount of energy emitted from the pixel, where the context does not assume any role. Conversely, the application of object-oriented image analysis on very high resolution data allows obtaining, by an automatic or semi-automatic analysis – with a minimal manual participation – a good classification also in presence of high and very high resolution data of small cities, where higher is an error possibility. Object-oriented image classification involves identification of image objects, or segments, that are spatially contiguous pixels of similar texture, color, and tone.
A simplified methodology using the object oriented image analysis for automatic road extraction for the Colombo City Area is presented in this paper. The proposed object-oriented image classification method comprises few fundamental and important steps towards content analysis and image understanding for instant image segmentation and classification. Few algorithms and techniques for the segmentation and classification in order to identify road features from satellite images were also supported to the proposed method.