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Topographic Maps (topographic + map)
Selected AbstractsUtilization of laser range finder and differential GPS for high-resolution topographic measurement at Hacitu,rul Tepe, TurkeyGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 2 2009Yuichi S. Hayakawa Topographic maps are fundamental for geoarchaeological field studies and archaeological excavations. However, traditional methods of topographic mapping, as well as modern high-tech methods such as airborne laser scanning and photogrammetry of high-resolution satellite images, are often cost-ineffective for field studies in terms of time, money, and labor. We here propose a method to measure topography for archaeological sites and surrounding areas quickly and accurately, using a laser range finder (LRF) and differential global positioning system DGPS. Three-dimensional coordinates of points on land surfaces are measured through the LRF, targeted from multiple measuring locations whose positions are acquired with the DGPS. The point data are then interpolated to produce a digital elevation model (DEM) using a geographic information system (GIS). High-resolution DEMs can be obtained with this method, with horizontal and vertical accuracies on the order of 10 cm. We here demonstrate the method for measuring detailed topography of the Hacitu,rul Tepe in central Turkey. Digital topography data incorporated in GIS can also be part of an archaeological database, providing opportunities for quantitative analyses of topography and archaeological materials. © 2009 Wiley Periodicals, Inc. [source] Retina development in zebrafish requires the heparan sulfate proteoglycan agrinDEVELOPMENTAL NEUROBIOLOGY, Issue 7 2008I-Hsuan Liu Abstract Recent studies from our laboratory have begun to elucidate the role of agrin in zebrafish development. One agrin morphant phenotype that results from agrin knockdown is microphthalmia (reduced eye size). To begin to understand the mechanisms underlying the role of agrin in eye development, we have analyzed retina development in agrin morphants. Retinal differentiation is impaired in agrin morphants, with retinal lamination being disrupted following agrin morpholino treatment. Pax 6.1 and Mbx1 gene expression, markers of eye development, are markedly reduced in agrin morphants. Formation of the optic fiber layer of the zebrafish retina is also impaired, exhibited as both reduced size of the optic fiber layer, and disruption of retinal ganglion cell axon growth to the optic tectum. The retinotectal topographic projection to the optic tectum is perturbed in agrin morphants in association with a marked loss of heparan sulfate expression in the retinotectal pathway, with this phenotype resembling retinotectal phenotypes observed in mutant zebrafish lacking enzymes for heparan sulfate synthesis. Treatment of agrin morphants with a fibroblast growth factor (Fgf) receptor inhibitor, rescue of the retinal lamination phenotype by transplantation of Fgf8-coated beads, and disruption of both the expression of Fgf-dependent genes and activation of ERK in agrin morphants provides evidence that agrin modulation of Fgf function contributes to retina development. Collectively, these agrin morphant phenotypes provide support for a crucial role of agrin in retina development and formation of an ordered retinotectal topographic map in the optic tectum of zebrafish. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008. [source] New Traversability Indices and Traversability Grid for Integrated Sensor/Map-Based NavigationJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 3 2003Homayoun Seraji This paper presents new measures of terrain traversability at short range and long range of a mobile robot; namely, local and global traversability indices. The sensor-based local traversability index is related by a set of linguistic rules to large obstacles and surface softness within a short range of the robot measured by on-board sensors. The map-based global traversability index is obtained from the terrain topographic map, and is based on major surface features such as hills and lakes within a long range of the robot. These traversability indices complement the mid-range sensor-based regional traversability index introduced earlier. Each traversability index is represented by four fuzzy sets with the linguistic labels {POOR, LOW, MODERATE, HIGH}, corresponding to surfaces that are unsafe, moderately-unsafe, moderately-safe, and safe for traversal, respectively. The global terrain analysis also leads to the new concepts of traversability map and traversability grid for representation of terrain quality based on the global map information. The traversability indices are used in two sensor-based traverse-local and traverse-regional behaviors and one map-based traverse-global behavior. These behaviors are integrated with a map-based seek-goal behavior to ensure that the mobile robot reaches its goal safely while avoiding both sensed and mapped terrain hazards. This provides a unified system in which the two independent sources of terrain quality information, i.e., prior maps and on-board sensors, are integrated together for reactive robot navigation. The paper is concluded by a graphical simulation study. © 2003 Wiley Periodicals, Inc. [source] Assessment of soil erosion hazard and prioritization for treatment at the watershed level: Case study in the Chemoga watershed, Blue Nile basin, EthiopiaLAND DEGRADATION AND DEVELOPMENT, Issue 6 2009W. Bewket Abstract Soil erosion by water is the most pressing environmental problem in Ethiopia, particularly in the Highlands where the topography is highly rugged, population pressure is high, steeplands are cultivated and rainfall is erosive. Soil conservation is critically required in these areas. The objective of this study was to assess soil erosion hazard in a typical highland watershed (the Chemoga watershed) and demonstrate that a simple erosion assessment model, the universal soil loss equation (USLE), integrated with satellite remote sensing and geographical information systems can provide useful tools for conservation decision-making. Monthly precipitation, soil map, a 30-m digital elevation model derived from topographic map, land-cover map produced from supervised classification of a Land Sat image, and land use types and slope steepness were used to determine the USLE factor values. The results show that a larger part of the watershed (>58 per cent of total) suffers from a severe or very severe erosion risk (>80,t,ha,1,y,1), mainly in the midstream and upstream parts where steeplands are cultivated or overgrazed. In about 25 per cent of the watershed, soil erosion was estimated to exceed 125,t,ha,1,y,1. Based on the predicted soil erosion rates, the watershed was divided into six priority categories for conservation intervention and 18 micro-watersheds were identified that may be used as planning units. Finally, the method used has yielded a fairly reliable estimation of soil loss rates and delineation of erosion-prone areas. Hence, a similar method can be used in other watersheds to prepare conservation master plans and enable efficient use of limited resources. Copyright © 2009 John Wiley & Sons, Ltd. [source] Morphometric analysis of neuromuscular topography in the serratus anterior muscleMUSCLE AND NERVE, Issue 3 2006S. Potluri PhD Abstract Groups of neurons form ordered topographic maps on their targets, and defining the mechanisms that develop such maps, and reconnect them after disruption, has biological as well as clinical importance. The neuromuscular system is an accessible and well-studied model for defining the principles that guide map formation, both during its development and its reformation after motor nerve damage. We present evidence for the expression of this map at the level of nerve terminal morphology and muscle fiber type in the serratus anterior muscle. Morphometric analyses indicate, first, a rostrocaudal difference in nerve terminal size depending on the ventral root of origin of the axons. Second, motor endplates are larger on type IIB than type IIA muscle fibers. Third, whereas IIB muscle fibers are distributed rather evenly along the rostrocaudal axis of the muscle, the more rostral type IIB fibers are preferentially innervated by anteriorly derived (C6) motor neurons, and more caudal IIB fibers are preferentially innervated by posteriorly derived (C7) motor neurons. This inference is supported by analysis of the size of nerve terminals formed in each muscle sector by rostral and caudal roots, and by evidence that the larger terminals are on IIB fibers. These results demonstrate a subcellular expression of neuromuscular topography in the serratus anterior muscle (SA) muscle in the form of differences in nerve terminal size. These results provide deeper insights into the organization of a neuromuscular system. They also offer a rationale for a topographic map, that is, to allow spinal motor centers to activate selectively different compartments within a muscle. Muscle Nerve, 2006 [source] Evolution of channel morphology and hydrologic response in an urbanizing drainage basinEARTH SURFACE PROCESSES AND LANDFORMS, Issue 9 2006Peter A. Nelson Abstract The Dead Run catchment in Baltimore County, Maryland, has undergone intense urbanization since the late 1950s. Reconstruction of the channel planform from topographic maps dating back to the 1890s and aerial photographs dating back to the 1930s indicates that the channel has remained stable in planform since at least the 1930s. The relative stability of Dead Run contrasts with the alterations in channel morphology reported for other urbanizing streams in the Piedmont physiographic province of the eastern United States. Trend analyses of discharge records in Dead Run show that urban development and stormwater control measures have had significant impacts on the hydrologic response of the catchment. The flood hydraulics of the Dead Run catchment are examined for the event that occurred on 22 June 1972 in association with Hurricane Agnes. A two-dimensional hydraulic model, TELEMAC-2D, was used with a finite-element mesh constructed from a combination of high-resolution LiDAR topographic data and detailed field survey data to analyse the distribution of boundary shear stress and unit stream power along the channel and floodplain during flooding from Hurricane Agnes. The spatial and temporal distributions of these parameters, relative to channel gradient and channel/valley bottom geometry, provide valuable insights on the stability of the Dean Run channel. The stability of Dead Run's channel planform, in spite of extreme flooding and decades of urban development, is most likely linked to geological controls of channel and floodplain morphology. Copyright © 2006 John Wiley & Sons, Ltd. [source] The termination of the last major phase of aeolian sand movement, coastal dunefields, DenmarkEARTH SURFACE PROCESSES AND LANDFORMS, Issue 7 2006Lars B. Clemmensen Abstract Optically stimulated luminescence (OSL) dating of sand samples from stabilized (or inactive) coastal dunes in Denmark provides information on the age of the termination phase of the last major aeolian activity period. A total of 26 sand samples were taken from four different coastal dunefields around the North Sea, Skagerrak and Kattegat coasts of Denmark. The OSL dates indicate that the last major phase of aeolian activity terminated between ad 1860 and 1905. Most of the dunes examined in this study were active around 1820, during a period documented to have been very stormy. A dune management scheme started around 1792, and this no doubt was a major cause of dunefield stabilization, but an overall decline of storminess, particularly spring and summer storminess, around the end of the 19th century must also have contributed to the increasing inactivity of coastal dunes. The new OSL dates on aeolian sand movement agree well with historical data and data from topographic maps on dune movement. This agreement supports the observation from earlier work that OSL dating of recent aeolian sand movement is accurate over the last few decades to centuries. Copyright © 2005 John Wiley & Sons, Ltd. [source] Modelling land use changes and their impact on soil erosion and sediment supply to riversEARTH SURFACE PROCESSES AND LANDFORMS, Issue 5 2002Anton J. J. Van Rompaey Abstract The potential for surface runoff and soil erosion is strongly affected by land use and cultivation. Therefore the modelling of land use changes is important with respect to the prediction of soil degradation and its on-site and off-site consequences. Land use changes during the past 250 years in the Dijle catchment (central Belgium) were analysed by comparing four historical topographic maps (1774, 1840, 1930 and 1990). A combination of land use transformation maps and biophysical land properties shows that certain decision rules are used for the conversion of forest into arable land or vice versa. During periods of increasing pressure on the land, forests were cleared mainly on areas with low slope gradients and favourable soil conditions, while in times of decreasing pressure land units with steep and unfavourable soil conditions were taken out of production. Possible future land use patterns were generated using stochastic simulations based on land use transformation probabilities. The outcome of these simulations was used to assess the soil erosion risk under different scenarios. The results indicate that even a relatively limited land use change, from forest to arable land or vice versa, has a significant effect on regional soil erosion rates and sediment supply to rivers. Copyright © 2002 John Wiley & Sons, Ltd. [source] Geographic distribution and population size of the mountain tapir (Tapirus pinchaque) in ColombiaJOURNAL OF BIOGEOGRAPHY, Issue 1 2002D. J. Lizcano Aim We conducted a study to estimate the past and present distribution and population size of T. pinchaque in Colombia. Location The study included all mountain ranges above 2000 m. Methods The past distribution was obtained by plotting on a map of past distribution of montane rain forests, the geographical locations with the name `danta' or `tapir' above 2000 m obtained from topographic maps, the locations cited in bibliographic references, and the results of interviews in the 530 Andean municipalities. The present distribution was obtained by plotting the present distribution of montane rain forests, the results of interviews and ground control. Population size was estimated by combining measurements of population density with maps of present distribution. Results In the past, the species occurred in the central and eastern Cordilleras, as well as in the Andean Massive where the three cordilleras merge in the south of the country. Currently, the species occurs in the central Andes south of Nevados National Park, and in the eastern Andes, south of Paramo de Sumapaz, Bogotá. According to our most optimistic estimates, there are about 2500 tapirs in the Andes of Colombia. Main conclusions These individuals occur in a total of thirty-five forest patches that range from 5 to 3700 km2. Only five to six fragments have the minimum necessary size (826 km2) to maintain at least 150 individuals, the estimated number to maintain viable population in the short term. The populations most threatened are those of the central Cordillera between P.N. Las Hermosas and P.N. Nevado del Huila where large tracts of mature montane forests are being converted to opium fields. [source] Morphometric analysis of neuromuscular topography in the serratus anterior muscleMUSCLE AND NERVE, Issue 3 2006S. Potluri PhD Abstract Groups of neurons form ordered topographic maps on their targets, and defining the mechanisms that develop such maps, and reconnect them after disruption, has biological as well as clinical importance. The neuromuscular system is an accessible and well-studied model for defining the principles that guide map formation, both during its development and its reformation after motor nerve damage. We present evidence for the expression of this map at the level of nerve terminal morphology and muscle fiber type in the serratus anterior muscle. Morphometric analyses indicate, first, a rostrocaudal difference in nerve terminal size depending on the ventral root of origin of the axons. Second, motor endplates are larger on type IIB than type IIA muscle fibers. Third, whereas IIB muscle fibers are distributed rather evenly along the rostrocaudal axis of the muscle, the more rostral type IIB fibers are preferentially innervated by anteriorly derived (C6) motor neurons, and more caudal IIB fibers are preferentially innervated by posteriorly derived (C7) motor neurons. This inference is supported by analysis of the size of nerve terminals formed in each muscle sector by rostral and caudal roots, and by evidence that the larger terminals are on IIB fibers. These results demonstrate a subcellular expression of neuromuscular topography in the serratus anterior muscle (SA) muscle in the form of differences in nerve terminal size. These results provide deeper insights into the organization of a neuromuscular system. They also offer a rationale for a topographic map, that is, to allow spinal motor centers to activate selectively different compartments within a muscle. Muscle Nerve, 2006 [source] Evolution of the Irrawaddy delta region since 1850THE GEOGRAPHICAL JOURNAL, Issue 2 2010PETER J HEDLEY We present a time series of coastline change for the Irrawaddy delta region of Myanmar using the earliest available navigation chart from 1850, and a set of topographic maps and satellite imagery dating from 1913 to 2006. Despite the large sediment load delivered annually to the gulf by the Irrawaddy and Salween Rivers, the coastline has been largely stable for 156 years, advancing at an average rate of no more than 0.34 km per century since 1925. The long-term average rate of increase in land area across the study area between 1925 and 2006 is 4.2 km2/year, but this masks a period of more rapid accumulation between 1925 and 1989 (8.7 km2/year), followed by a period of net erosion at a rate of 13 km2/year until 2006. Less than 9% of the sediment load delivered to the study region by the Irrawaddy, Salween and Sittoung Rivers has contributed to the observed progradation, with the remainder being exported into the Gulf of Martaban to depths below low tide level, or filling any accommodation space created due to subsidence or sea level rise. In contrast to many deltas worldwide, we suggest that the coastline encompassing the Irrawaddy delta and the Salween River is more or less in equilibrium, and that sediment deposition currently balances subsidence and sea level rise. Myanmar has fewer large dams relative to its Asian neighbours, and the Salween is currently undammed. This is forecast to change in the next 5,10 years with extensive damming projects on the mainstem of the Salween under consideration or construction, and the sediment retention will cause losses in sediment supply to the Gulf of Martaban, and retreat of the delta. This could impact the densely populated delta region and Yangon, and further exacerbate the impacts of extreme events such as Cyclone Nargis in 2008. [source] Mapping Systems and GIS: A Case Study using the Ghana National GridTHE GEOGRAPHICAL JOURNAL, Issue 4 2000GRAHAM THOMAS The problem of incompatible projections and conversion between mapping systems is of general concern to those involved in the collection of natural resources data. The Ghana National Grid (GNG) is an example of a mapping system that is not defined in image processing and GIS software and for which the transformation parameters are not readily available in the literature. Consequently, integrating GNG topographic map data within a GIS with data derived from other sources can be problematic. In this paper a practical solution for deriving the required transformation parameters to convert from the World Geodetic System of 1984 (WGS84) to the GNG system is demonstrated. The method uses a single geodetic control point, available 1:50 000 topographic maps and a SPOT satellite panchromatic image geo-referenced to GNG. The resultant parameters are applied to road survey data in Universal Transverse Mercator (UTM) format for overlay with the SPOT image. Despite the approximations made in applying the method, when compared against official estimates of the datum transformation parameters, this relatively simple procedure resulted in estimates that appear acceptable in regard to combining data sets at a nominal scale of 1:50000. [source] Assessment of impact of aquaculture on Kolleru Lake (India) using remote sensing and Geographical Information SystemAQUACULTURE RESEARCH, Issue 16 2006Marappan Jayanthi Abstract Aquaculture is one of the fastest growing food industries and the rapid growth of aquaculture worldwide has resulted in growing concerns about its impact on important ecosystems. Kolleru Lake, India's largest fresh water body, and Ramsar site have undergone tremendous changes due to the development of aquaculture. To assess the impact of aquaculture on Kolleru, satellite data were found appropriate because of the synoptic-detailed overview and accuracy. Satellite data of IRS 1D, LISS III from 2004 and Survey of India topographic maps from 1967 were processed using image processing techniques in erdas imagine and analysed in Geographical Information System (GIS) such as arc gis 9.1. Land use map prepared from the satellite data was verified in the field using Global Positioning System to check the land and water use classes and its areal extent. It was estimated from the topographic maps of 1967 that the total lake boundary area was 180.38 km2, in which 70.70 km2 had water throughout the year and 100.97 km2 had water during the rainy season. The digital image processing of 2004 satellite data revealed that Kolleru was no longer a lake and the lake area of 62.65 km2 (34.73%) only remained in a degraded state, extensively colonized by macrophytes. The total loss of lake area was 109.02 km2 between 1967 and 2004, in which aquaculture was developed in 99.74 km2, which represented 55.3% of the 1967 lake area. The maximum conversion to aquaculture occurred from the lake liable to be inundated during the 1967 rainy season. The area under agriculture was 16.62 km2 in 2004, the increase in lake area for agriculture between 1967 and 2004 being 8.22 km2 (4.55% of lake). If human induced degradation is allowed to continue, the lake will very soon disappear. Now, the Government of Andhra Pradesh, India, has initiated schemes and laws to restore the lake to its pre-development state. Lessons learnt from the Kolleru Lake cautioned that there is a need for regular monitoring of important water resources throughout the world to protect the biodiversity of the earth. [source] GIS in archaeology,the interface between prospection and excavationARCHAEOLOGICAL PROSPECTION, Issue 3 2004Wolfgang NeubauerArticle first published online: 12 MAY 200 Abstract Archaeological prospection and excavation have the same research objective, namely, the study of the material culture of humans. They investigate the archaeological record but are based on different physical properties and work with different resolution and instrumentation. In addition to the study of literature concerning antique discoveries and the collection and evaluation of surface finds, it is aerial archaeology and geophysical prospection that are the most suitable methods of achieving the intended goal. Aerial photographs provide the archaeologist with a large-scale overview, and digital photogrammetric evaluation provides very detailed topographic maps and orthophotographs of the archaeological structures visible on the surface. These structures appear in various forms, through contrasts in the physical properties between the structures themselves and the material that surrounds them. In geophysical prospection, the contrasts between the physical properties of the archaeological structures and the surrounding material usually can be investigated only in the near-surface or with direct ground contact. These contrasts are not directly visible, however, and must instead be measured and converted into a comprehensible visualization. The prospection methods used in the interpretation process are not significantly different from one to another. Interpretation encompasses the localization and classification of archaeological structures, the analysis of their spatial relationships, as well as the creation of models showing the main stratification at a site. Unlike excavations, through archaeological interpretation of prospection data, various accurate archaeological models of the entire site and the surrounding landscape can be made available rapidly. These models can be used for targeted excavations, so as to further condense the information and to refine the models. If all the data are made available in a geographical information system (GIS), it can be combined and further analysed by the excavator as well as by the prospector. Copyright © 2004 John Wiley & Sons, Ltd. [source] Human,environment interactions in residential areas susceptible to landsliding: the Flemish Ardennes case studyAREA, Issue 3 2010Miet Van Den Eeckhaut Studies on landslide susceptibility and landslide risk generally start from the assumption that mainly natural factors control the occurrence of landslides. The role of human activity is considered less important. We investigated the role of human,environment interactions in the Flemish Ardennes, Flanders' most landslide-susceptible region. The establishment of a detailed landslide inventory brought insight into the spatial occurrence of landslides and into the different landslide types and characteristics. A statistical model, i.e. logistic regression, allowed the significance of environmental factors controlling landslide occurrence to be determined, and a landslide susceptibility map to be produced. Being a residential area, however, the Flemish Ardennes is a region where humans play an active role with regard to landslide risk. Although the location of many archaeological sites in this area is known, almost no archaeological sites are found on landslide-susceptible hillslopes. This might indicate that in prehistorical and historical times humans were more familiar with local environmental characteristics and avoided unstable hillslopes. Comparison of topographic maps (1777,2001), on the contrary, indicate that over the last 250 years buildings and other infrastructures have been constructed on old landslides. Given that humans are living, working and driving on or close to unstable hillslopes, the landslide risk has therefore increased. The landslide inventory map and the landslide susceptibility map are important tools for landslide risk reduction. Here ,science meets policy', as both maps allow linking construction norms and other mitigation measures to hillslopes already affected by landslides and to susceptibility classes with very high, high and moderate landslide susceptibility. [source] Computerized corneal topography in a paediatric population with Down syndromeCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 1 2005Clinical Science Abstract Purpose:,To characterize abnormal corneal topographic changes using corneal computerized videokeratography (CVK) in a paediatric population with Down syndrome, and in their parents. Methods:,Prospective, non-randomized clinical trial. Twenty-one children with Down syndrome (mean age 6.9 years) recruited from The Hospital for Sick Children, 18 of their parents, and a paediatric control group of 60 otherwise well children (mean age 9 years), underwent complete ocular examination and CVK using the EyeSys system. Corneal topographic maps were assessed subjectively, and three objective parameters analysed: central corneal power (CP), difference in central corneal power between the two eyes (DCP), and inferior,superior steepening asymmetry (I-S). Results:,Corneal curvature in children with Down syndrome was significantly steeper than in the paediatric control population (CP 46.66 vs 42.60 D, P < 0.0001), but changes with age paralleled that of the control population. DCP and I-S values were also significantly different from the control population (P < 0.0001). 39% of the parents of children with Down syndrome had at least one abnormal parameter. Conclusions:,This study demonstrates that CVK is a useful tool in the ocular assessment of patients with Down syndrome. The findings suggest that this patient population have abnormalities of corneal shape even in the absence of clinical evidence of keratoconus. A greater than expected incidence of abnormal topographic changes was observed in the parents of these patients. [source] A database of retinal topographic mapsCLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 1 2008John D Pettigrew Emeritus Professor No abstract is available for this article. [source] | ||||||||||||||||