Strip Map Research Articles

Beam scan mode analysis and design for geosynchronous SAR

The beam velocity of geosynchronous synthetic aperture radar (GEO SAR) varies seriously with the orbital position and the scene position, which leads to a significant variation of the scene length and the azimuth resolution in the stripmap (SM) mode. To obtain uniform scene length and azimuth resolution, beam scan modes can be utilized in GEO SAR, such as the sliding spotlight (SLL) mode and the terrain observation by progressive scans (TOPS) mode. However, the conventional design method of the beam scan mode is based on the straight line model (SLM), which does not consider the effects of the curved satellite track and the spherical earth surface. To solve this problem, a curvature circle model (CCM) is proposed considering the actual satellite-earth relationship. By using the CCM, the beam velocity after the beam scan is derived. The scene length and the azimuth resolution are analyzed. The SLL mode and the TOPS mode are recommended for GEO SAR. After that, a design method of the beam scan mode is proposed based on the CMM. The performance of the proposed method is verified by computer simulations.

Groupwise structural parcellation of the whole cortex: A logistic random effects model based approach

Current theories hold that brain function is highly related to long-range physical connections through axonal bundles, namely extrinsic connectivity. However, obtaining a groupwise cortical parcellation based on extrinsic connectivity remains challenging. Current parcellation methods are computationally expensive; need tuning of several parameters or rely on ad-hoc constraints. Furthermore, none of these methods present a model for the cortical extrinsic connectivity of the cortex. To tackle these problems, we propose a parsimonious model for the extrinsic connectivity and an efficient parceling technique based on clustering of tractograms. Our technique allows the creation of single subject and groupwise parcellations of the whole cortex. The parcellations obtained with our technique are in agreement with structural and functional parcellations in the literature. In particular, the motor and sensory cortex are subdivided in agreement with the human homunculus of Penfield. We illustrate this by comparing our resulting parcels with the motor strip mapping included in the Human Connectome Project data.

Convolutions of harmonic half-plane mappings with harmonic vertical strip mappings

In the present paper, we prove the convolutions of generalized harmonic right half-plane mappings with harmonic vertical strip mappings are univalent and convex in the horizontal direction. Moreover, some examples of harmonic univalent mappings convex in the horizontal direction are also constructed to illuminate the main results.

To Know the Distance: Wayfinding and Roadmaps of Early Modern England and France

In 1675, John Ogilby produced his road atlas with strip maps which not only arrived with fanfare, but spawned several more publications that aimed to be user-friendly. As with many maps and atlases from the London printing trade, the objectives were to serve consumers, acquire a piece of the market, and have an outlet for a new edition. Across the Channel, however, the road network of France, as with other public works, was not only state-directed but a tool of state power. Not until nearly one hundred years later did Claude-Sidoine Michel and Louis-Charles Desnos produce L'Indicateur Fidèle, which provided strip maps for merchants, navigators, and travelers. This publication emerged out of the French national mapping project directed by the Cassini family. In the interim, while French map makers produced maps with an appeal to serving the state, they, like their London contemporaries, also hoped to maintain a thriving business and attract an audience, often through the traditional French social institution of patronage. The purpose of this comparative study of (post) road maps and atlases of England and France is to investigate the role of the government and the publishing trade in the production of these works.

Monitoring the slope movement of the Shuping landslide in the Three Gorges Reservoir of China, using X-band time series SAR interferometry

As the largest water conservation project in China, the Three Gorges Reservoir has attracted a lot of attention. However, the rise in water level due to the dam operation has caused many ecological problems. Since the impoundment of the Three Gorges Reservoir in the year 2003, many landslides have taken place. The Shuping landslide is a reactivated landslide and has been continuously moving since the impoundment. It has resulted in serious dangers to local residence and the role of the Yangtze River as an inland waterway. Spaceborne Synthetic Aperture Radar (SAR) sensors obtain images periodically and regionally, from which the characteristics of the slope movement could be obtained timely and cost effectively. In this study, an adapted time series InSAR technique considering SRTM bias is proposed and used to process TerraSAR-X strip map images with 3 meters resolution which collected in the first quarter of 2012. Compared with previous studies with low resolution SAR data, our results obtain much more stable points and reveal the movement pattern of the active slope of Shuping landslide in detail, and they show that there are two main landslide bodies obviously; one is located in the eastern part of the landslide, while the other is located in the western part of the landslide, the movement velocity is up to 40mmmonth−1, and the results are well-consistent with the in situ results. Furthermore the active movement boundaries was identified through analysing the time series InSAR results, the shape of the landslide is chair-like, and the boundaries lie mostly along ditches. The results show that more details about the landslide could be revealed using the proposed time series InSAR method and high resolution TerraSAR-X SAR data, and this provide a more comprehensive way for landslide movement monitoring, which will be useful for landslide management.

Convex Combinations of Planar Harmonic Mappings Realized Through Convolutions with Half-Strip Mappings

Recent investigations into what geometric properties are preserved under the convolution of two planar harmonic mappings on the open unit disk $${\mathbb {D}}$$ have typically involved half-plane and strip mappings. These results rely on having a convolution that is locally univalent and sense-preserving on $${\mathbb {D}}$$ , and thus, much focus has been on trying to satisfy this condition. We introduce a family of right half-strip harmonic mappings, $$\Psi _c : {\mathbb {D}}\rightarrow {\mathbb {C}}$$ , $$c>0$$ , and consider the convolution $$\Psi _c * f$$ for a harmonic mapping $$f = h +\overline{g}: {\mathbb {D}}\rightarrow {\mathbb {C}}$$ . We prove it is sufficient for $$h \pm g$$ to be starlike for $$\Psi _c *f$$ to be locally univalent and sense-preserving. Moreover, $$\Psi _c * f$$ decomposes into a convex combination of two harmonic mappings, one of which is f itself. This decomposition is key in addressing mapping properties of the convolution, and from it, we produce a family of convex octagonal harmonic mappings as well some other families of convex harmonic mappings. Additionally, motivated by the construction of $$\Psi _c$$ , we introduce a generalized harmonic Bernardi integral operator. We demonstrate convolution preserving properties and a weak subordination relationship for this extended operator.

TEACHING ENGLISH GRAMMAR WITH CLT AND EXPLANATION METHOD

<p>Teaching English grammar can be taught by some methods. Two of them are communicative language teaching (CLT) and explanation method. Both CLT and explanation method can be used to present the English language materials such as authentic materials, Scrambled sentences, language games, picture strip stories, poems, songs, poetry, map, and role play. Each of them has strength and weakness. Teaching with CLT can make the class become interesting and the student will not get bored. Whereas, by only using the explanation the student will get bored and the teacher as well. In Indonesia CLT is a modified version to adopt teaching English skills such as reading, writing and and speaking. Structural approach is still applied for teaching language elements such as structure/grammar and vocabulary. Explanation method is used to develop reading skill. However, based on the data of test result by the students, the result of explanation technique is more effectively targeted better than CLT.</p><p> <strong><em>Keywords</em></strong>: <em>grammar</em>, <em>communicative</em>, <em>explanation</em>, <em>technique</em>, <em>teaching</em></p>

Landslide Deformation Analysis by Coupling Deformation Time Series from SAR Data with Hydrological Factors through Data Assimilation

Time-series SAR/InSAR techniques have proven to be effective tools for measuring landslide movements over large regions. Prior studies of these techniques, however, have focused primarily on technical innovation and applications, leaving coupling analysis of slope displacements and trigging factors as an unexplored area of research. Linking potential landslide inducing factors such as hydrology to SAR/InSAR derived displacements is of crucial importance for understanding landslide deformation mechanisms and could support the development of early-warning systems for disaster mitigation and management. In this study, a sequential data assimilation method named the Ensemble Kalman filter (EnKF), is adopted to explore the response mechanisms of the Shuping landslide movement in relation to hydrological factors. Previous research on the Shuping landslide area shows that the reservoir water level and rainfall are the two main triggering factors in slope failures. To extract the time-series deformations for the Shuping landslide area, Pixel Offset Tracking (POT) technique with corner reflectors was adopted to process the TerraSAR-X StripMap (SM) and High-resolution Spotlight (HS) images. Considering that these triggering factors are the primary causes of displacement fluctuations in periodic displacement, time-series decomposition was carried out to extract the periodic displacement from the POT measurements. The correlations between the periodic displacement and the inducing factors were qualitatively estimated through a grey relational analysis. Based on this analysis, the EnKF method was adopted to explore the response relationships between the displacements and triggering factors. Preliminary results demonstrate the effectiveness of EnKF in studying deformation response mechanisms and understanding landslide development processes.

Strip maps of small surfaces are convex

The strip map is a natural map from the arc complex of a bordered hyperbolic surface $S$ to the vector space of infinitesimal deformations of $S$. We prove that the image of the strip map is a convex hypersurface when $S$ is a surface of small complexity: the punctured torus or thrice punctured sphere.

The contribution of maps to appreciating physical landscape: examples from Derbyshire's Peak District

Abstract It is only in the last 100 years or so that most of Britain has been covered by accurate, published, topographic and geological maps. Although travellers’ guides were available from the late seventeenth century, they lacked adequate maps. Whilst fairly accurate maps of the major roads were published in the early seventeenth century as strip maps, topographic maps were not generally available until the nineteenth century. Cartographers, usually when preparing county maps, struggled with the representation of Britain's varied topography. In the nineteenth century, medium-scale (1-inch-to-the-mile) topographic maps initially developed through the agency of the prizes offered by the Royal Society of Arts but primarily due to the Ordnance Survey. Geological maps benefitted from improved base maps – those of John Cary and the Ordnance Survey. This paper especially explores and illustrates the development of maps and the role they played in the depiction and understanding of landscape and promotion of the major early geotourism region of the Peak District from 1780 to 1930.

The laser linewidth effect on the image quality of phase coded synthetic aperture ladar

The phase coded (PC) waveform in synthetic aperture ladar (SAL) outperforms linear frequency modulated (LFM) signal in lower side lobe, shorter pulse duration and making the rigid control of the chirp starting point in every pulse unnecessary. Inherited from radar PC waveform and strip map SAL, the backscattered signal of a point target in PC SAL was listed and the two dimensional match filtering algorithm was introduced to focus a point image. As an inherent property of laser, linewidth is always detrimental to coherent ladar imaging. With the widely adopted laser linewidth model, the effect of laser linewidth on SAL image quality was theoretically analyzed and examined via Monte Carlo simulation. The research gives us a clear view of how to select linewidth parameters in the future PC SAL systems.

Linear Combinations of Univalent Harmonic Mappings Convex in the Direction of the Imaginary Axis

In the present paper, we introduce a family of univalent harmonic mappings, which map the unit disk onto domains convex in the direction of the imaginary axis. We find conditions for the linear combinations of mappings from this family to be univalent and convex in the direction of the imaginary axis. Linear combinations of functions from this family and harmonic mappings obtained by shearing of analytic vertical strip mappings are also studied.

Sentinel-1A Product Geolocation Accuracy: Commissioning Phase Results

Sentinel-1A (S1A) is an Earth observation satellite carrying a state-of-the-art Synthetic Aperture Radar (SAR) imaging instrument. It was launched by the European Space Agency (ESA) on 3 April 2014. With the end of the in-orbit commissioning phase having been completed at the end of September 2014, S1A data products are already consistently providing highly accurate geolocation. StripMap (SM) mode products were acquired regularly and tested for geolocation accuracy and consistency during dedicated corner reflector (CR) campaigns. At the completion of this phase, small geometric inconsistencies had been understood and mitigated, with the high quality of the final product geolocation estimates reflecting the mission’s success thus far. This paper describes the measurement campaign, the methods used during geolocation estimation, and presents best estimates of the product Absolute Location Error (ALE) available at the beginning of S1A’s operational phase.

Landslide deformation monitoring using point-like target offset tracking with multi-mode high-resolution TerraSAR-X data

Many landslides in the Three Georges area have shown active deformations associated with water level fluctuations since the full operation of the Three Georges Dam. Such active deformations of landslide bodies need to be closely monitored for disaster prevention and warning. One way to do this is to employ SAR pixel offset tracking, a powerful technique that can be used for measuring two-dimensional large displacements. As an improvement of the original pixel offset tracking technique, the point-like target (PT) offset tracking method focuses on stable point-like targets and thus can obtain more reliable measurements. In this paper, the PT offset tracking method is employed to investigate historical evolution of the Shuping landslide, using time series TerraSAR-X data acquired in both Stripmap (SM) and High-resolution Spotlight (HS) modes. Artificial corner reflectors (CR) installed at/near the landslide are identified as PTs and used to analyze the spatial–temporal pattern of landslide deformations. Results showed that the maximum accumulative deformation of the Shuping landslide reached more than 1.5m over a time span of two years. A correlation analysis between the deformation trends and the fluctuation of reservoir water level indicated that most deformations of the landslide happened during the water level declining period.

Ionized gas at the edge of the central molecular zone

To determine the properties of the ionized gas at the edge of the CMZ near Sgr E we observed a small portion of the edge of the CMZ near Sgr E with spectrally resolved [C II] 158 micron and [N II] 205 micron fine structure lines at six positions with the GREAT instrument on SOFIA and in [C II] using Herschel HIFI on-the-fly strip maps. We use the [N II] spectra along with a radiative transfer model to calculate the electron density of the gas and the [C II] maps to illuminate the morphology of the ionized gas and model the column density of CO-dark H2. We detect two [C II] and [N II] velocity components, one along the line of sight to a CO molecular cloud at -207 km/s associated with Sgr E and the other at -174 km/s outside the edge of another CO cloud. From the [N II] emission we find that the average electron density is in the range of about 5 to 25 cm{-3} for these features. This electron density is much higher than that of the warm ionized medium in the disk. The column density of the CO-dark H$_2$ layer in the -207 km/s cloud is about 1-2X10{21} cm{-2} in agreement with theoretical models. The CMZ extends further out in Galactic radius by 7 to 14 pc in ionized gas than it does in molecular gas traced by CO. The edge of the CMZ likely contains dense hot ionized gas surrounding the neutral molecular material. The high fractional abundance of N+ and high electron density require an intense EUV field with a photon flux of order 1e6 to 1e7 photons cm{-2} s{-1}, and/or efficient proton charge exchange with nitrogen, at temperatures of order 1e4 K, and/or a large flux of X-rays. Sgr E is a region of massive star formation which are a potential sources of the EUV radiation that can ionize the gas. In addition X-ray sources and the diffuse X-ray emission in the CMZ are candidates for ionizing nitrogen.

Surface displacements of the 2014 Cephalonia (Greece) earthquake using high resolution SAR interferometry

The island of Cephalonia (Western Greece), was struck by two strong seismic events, with magnitudes Mw = 6.0 and Mw = 5.9 which occurred on Jan. 26, 2014 and Feb. 3, 2014 respectively. The first event was located near Argostoli’s village, whereas the second one was located at the north part of Livadi village. These two strong seismic events were followed by smaller aftershocks provoking extensive crustal movements and structural damage effects. Differential Synthetic Aperture Radar Interferometry (DInSAR) is a powerful remote sensing tool for ground motion monitoring. Since the last two decades, DInSAR is widely used in a variety of applications including natural hazards such as earthquakes. In 2007, a high resolution X-band satellite namely TerraSAR-X was launched. Due to its short revisit cycle of 11 days and its short wavelength, it has a good potential to capture faster surface movements. This study refers to the application of the DInSAR using TerraSAR-X strip map data to monitor the co- and post-seismic surface deformation caused by the second seismic event. Using DInSAR methodology, three differential interferograms were calculated showing the displacement trend of the region, before and after the earthquake. Results demonstrate that the main part of the island shows stability to low uplift whereas in the western part a significant deformation pattern is observed. The findings permit a better understanding and identification of the local tectonic setting of the study area and the investigation of the reasons that some settlements were strongly affected by this seismic activity.

A New Imaging Method for Circular Trace Scanning SAR with Wide Observation

Circular Trace Scanning SAR is a new strip map mode SAR imaging in recent years, its imaging speed is fast with larger scene. This paper first establishes the imaging geometry right, by the four order approximation of the oblique distance model, combined with the series inversion method, and the removal of the coupling terms in the spectrum in the range Doppler domain, finally complete the azimuth compression. The simulation results prove the validity and feasibility of the imaging.

Evaluating the Quality and Accuracy of TanDEM-X Digital Elevation Models at Archaeological Sites in the Cilician Plain, Turkey

Satellite remote sensing provides a powerful instrument for mapping and monitoring traces of historical settlements and infrastructure, not only in distant areas and crisis regions. It helps archaeologists to embed their findings from field surveys into the broader context of the landscape. With the start of the TanDEM-X mission, spatially explicit 3D-information is available to researchers at an unprecedented resolution worldwide. We examined different experimental TanDEM-X digital elevation models (DEM) that were processed from two different imaging modes (Stripmap/High Resolution Spotlight) using the operational alternating bistatic acquisition mode. The quality and accuracy of the experimental DEM products was compared to other available DEM products and a high precision archaeological field survey. The results indicate the potential of TanDEM-X Stripmap (SM) data for mapping surface elements at regional scale. For the alluvial plain of Cilicia, a suspected palaeochannel could be reconstructed. At the local scale, DEM products from TanDEM-X High Resolution Spotlight (HS) mode were processed at 2 m spatial resolution using a merge of two monostatic/bistatic interferograms. The absolute and relative vertical accuracy of the outcome meet the specification of high resolution elevation data (HRE) standards from the National System for Geospatial Intelligence (NSG) at the HRE20 level.

Asymptotics in a family of linked strip maps

We apply round-off to planar rotations, obtaining a one-parameter family of invertible maps of a two-dimensional lattice. As the angle of rotation approaches π/2, the fourth iterate of the map produces piecewise-rectilinear motion, which develops along the sides of convex polygons.We characterise the dynamics–which resembles outer billiards of polygons–as the concatenation of so-called strip maps, each providing an elementary perturbation of an underlying integrable system. Significantly, there are orbits which are subject to an arbitrarily large number of these perturbations during a single revolution, resulting in the appearance of a novel discrete-space version of near-integrable Hamiltonian dynamics.We study the asymptotic regime of the limiting integrable system analytically, and numerically some features of its very rich near-integrable dynamics. We unveil a dichotomy: there is one regime in which the nonlinearity tends to zero, and a second where it does not. In the latter case, numerical experiments suggest that the distribution of the periods of orbits is consistent with that of random dynamics; in the former case the fluctuations result in an intricate structure of resonances.

Sections of stable harmonic convex functions

In this article, we consider the class SHC of normalized stable harmonic convex mappings f=h+g¯ in the unit disk and determine r such that every section of f is close-to-convex or convex in the disk ∣z∣<r. Also, we show that the convolution f∗f∈SHC whenever f∈SHC. In addition, we prove that the harmonic convolution f1∗f2 is stable harmonic close-to-convex whenever f1∈SHC and f2 is either a slanted half-plane mapping or an asymmetric vertical strip mapping or a mapping in the family PH0(α) which is contained in the family of harmonic close-to-convex functions in ∣z∣<1.