A Robust Texture Analysis and Classification Approach for Urban Land‐Use and Land‐Cover Feature Discrimination

Abstract

Attempts to analyze urban features and to classify land use and land cover directly from high‐resolution satellite data with traditional computer classification techniques have proven to be inefficient for two primary reasons. First, urban landscapes are composed of complex features. Second, traditional classifiers employ spectral information based on single pixel value and ignore a great amount of spatial information. Texture plays an important role in image segmentation and object recognition, as well as in interpretation of images in a variety of applications. This study analyzes urban texture features in multi‐spectral image data. Recent developments in the very powerful mathematical theory of wavelet transforms have received overwhelming attention by image analysts. An evaluation of the ability of wavelet transform in urban feature extraction and classification was performed in this study, with six types of urban land cover features classified. The preliminary results of this research indicate that the accuracy of texture analysis in classifying urban features in fine resolution image data could be significantly improved with the use of wavelet transform approach.     

Road Maps and Advertising in Britain 1860–1940

Abstract

To the writer's knowledge nothing has been published, at the time of writing, on British maps as a selling medium in the period 1860–1940. The only exception proves the rule: D. G. Hindley's Advertising in Victorian England 1837–1901 (see Sources) mentions Chas Baker's 1887 ABC Guide to London and Large Pocket Map of London (see below), but does not place it in its context. This means that the subject can only be studied through the maps themselves, against a background of society at the time.     

The Seventeenth-century Maps and Surveys of William Fowler

Abstract

Despite the recent publication of several dictionaries of surveyors and cartographers, little is known of the professional and personal background of the majority of such practitioners. This lack of detailed biographical analysis is particularly applicable to the surveyor in the seventeenth century. This paper examines the activities of one of the most prolific west Midlands' estate surveyors in that century, William Fowler. Present knowledge of surveying practice in that period is reviewed and Fowler's work is compared to this pattern. An appendix details Fowler's extant maps and surveys.     

Multi‐Temporal Study and Detailed Photogeological Mapping of the Armero Debris Flow (Colombia), Using Landsat TM 5 Images

Abstract

On November the 13^th of 1985, the City of Armero (Colombia) was destroyed by debris flows generated by a reactivation of the Nevado del Ruiz Volcano. The flows ocurred in at least three principal pulses, as was observed by the disater's survivors. Landsat TM 5 data processing was carried out in subscenes taken before and after the lahar sedimentation.

False color composites were generated and combined with the geological information available in order to visualize the magnitude of the catastrophe and the flow characteristics. Taking advantage of Landsat TM 5 images with high spectral resolution, a detailed photogeological mapping of the three principal pulses of the debris flows was carried out. Landsat TM 5 proved to be a powerful complementary source of information for hazard assesment of these catastrophic debris flows. The images were used in addition to ground‐based information, and were an easy way to help ordinary people and decision makers understand such hazardous volcanic situations.     

Numerical computation of spherical harmonics of arbitrary degree and order by extending exponent of floating point numbers

By extending the exponent of floating point numbers with an additional integer as the power index of a large radix, we compute fully normalized associated Legendre functions (ALF) by recursion without underflow problem. The new method enables us to evaluate ALFs of extremely high degree as 2³² =  4,294,967,296, which corresponds to around 1 cm resolution on the Earth’s surface. By limiting the application of exponent extension to a few working variables in the recursion, choosing a suitable large power of 2 as the radix, and embedding the contents of the basic arithmetic procedure of floating point numbers with the exponent extension directly in the program computing the recurrence formulas, we achieve the evaluation of ALFs in the double-precision environment at the cost of around 10% increase in computational time per single ALF. This formulation realizes meaningful execution of the spherical harmonic synthesis and/or analysis of arbitrary degree and order.     

Three Types of Reconnaissance Mapping

Abstract

This account of exploratory mapping is provided by a surveyor who started his working life as an explorer in areas where existing maps were extremely rough and rudimentary. Although the methods and results it describes will not stand comparison with modern topographical maps compiled from vertical air photographs, this frank and objective appraisal will help the 'chair-borne' cartographer to understand the importance of a thorough evaluation of some material of that type and age, which is still sometimes the best available until the new air surveys replace it.     

Evaluating urban public facilities of Shenzhen by application of open source data

Abstract

This article applies open source data of public facilities through data mining, not only to evaluate the public facilities from an objective dimension, but also to reflect the sensory opinions of the group factually, eventually realizing the evaluation measurement of urban public facilities. The research takes Shenzhen city as an empirical case and chooses typical public facilities to mine data, resolve address and weight to explore the application of public facilities evaluation under dimension reduction of open source data. The empirical study consists of three parts. First, as the objective evaluation, we estimate the density distribution and per capita of public facility through data mining and address resolution. Second, as the subjective evaluation, we carry on the location analysis to high-score public facility through attention and satisfaction data of Internet evaluation. Finally, as mentioned above, we calculate the weight of objective and subjective evaluation of public facility, eventually formatting the comprehensive evaluation of public facilities.     

Mapping spiny aster infestations with QuickBird imagery

QuickBird satellite imagery acquired in June 2003 and September 2004 was evaluated for detecting the noxious weed spiny aster [Leucosyris spinosa (Benth.) Greene] on a south Texas, USA rangeland area. A subset of each of the satellite images representing a diversity of cover types was extracted and used as a study site. The satellite imagery had a spatial resolution of 2.8 m and contained 11-bit data. Unsupervised and supervised classification techniques were used to classify false colour composite (green, red, and near-infrared bands) images of the study site. Imagery acquired in June was superior to that obtained in September for distinguishing spiny aster infestations. This was attributed to differences in spiny aster phenology between the two dates. An unsupervised classification of the June image showed that spiny aster had producer's and user's accuracies of 90% and 93.1%, respectively, whereas a supervised classification of the June image had producer's and user's accuracies of 90% and 81.8%, respectively. These results indicate that high resolution satellite imagery coupled with image analysis techniques can be used successfully for detecting spiny aster infestations on rangelands.     

SIR DAVID GILL AND THE GEODETIC SURVEY OF SOUTH AFRICA AND THE ARC OF THE 30TH MERIDIAN

Abstract

In the memoir of the late Capt. G. T. McCaw which appeared in the January number of this Review (vii, 47,2), reference was made to the part which the late Sir David Gill played in the origin of the work on the survey of the Arc of the 30th Meridian in Africa. This year is the centenary of Gill's birth, as he was born in June 1843, and it is therefore timely to give some account of his work during his long term of office as Her Majesty's Astronomer at the Cape which resulted inthe inception and completion of the Geodetic Survey of South Africa and the survey of the Arc to the southern shores of Lake Tanganyika. He died on 24th January 1914.     

Typographic Requirements of Cartography A Preliminary Note

Abstract

This paper, presented at the Society's Annual Technical Symposium held at Cambridge University in September 1972, summarises the results of a market survey conducted in 1970. Map ownership and usage are discussed and some conclusions are drawn as to possible future trends.     

Gaia Journeys: a museum-based immersive performance exploration of the Earth

Abstract

Gaia Journeys is a collaborative multimedia musical and virtual reality art performance conceived by author Williams, with the aid of staff at the Denver Museum of Nature & Science. Inspired by astronauts who spoke of seeing a border-less world from orbit, Gaia Journeys’ chief goal was to deliver this experience to museum audiences via photo-realistic virtual depictions of the Earth (from orbit as well as via spherical photographic panoramas taken from the ground) choreographed to live musical accompaniment. Gaia Journeys took place in the high resolution digital ‘fulldome’ Gates Planetarium, with Williams playing the violin and keyboards, enhancing a previously recorded backing track, while visuals were generated with SCISS AB's Uniview. The eight tracks of audio were three-dimensionally spatialised to the 16.4 sound system of the Gates Planetarium, providing an immersive sound experience to match the visuals. The audience feedback was generally positive, with great interest in repeat or similar future programming. These visitor evaluations suggest the potent power of the new class of digital planetaria for displaying virtual globe datasets to the public, via both multimedia entertainment like Gaia Journeys as well as traditional lectures.     

Arno Peters changed the World! Development Education and the Peters' Projection

Abstract

This paper describes, from a map librarian's perspective, an investigation into the feasibility of the provision of digital mapping for use by students in a British academic library. Establishing the funding has been a significant part of the project. This has included consideration of hardware as well as the pricing structures for the supply of digital cartographic data.     

'Drawing the Coral Heads': Mental Mapping and its Physical Representation in a Polynesian Community

Abstract

Indigenous people throughout the world developed their own mapping skills and systems of knowledge. While Westerners are prone to overlook these communities' geographical knowledge and imagine their mapping activities to be primitive or non-existent, their mental maps are often impressive in sophistication and detailed even if based on cosmologies that are quite foreign to Western thinking. This article depicts a mental map of the ocean floor shared by Polynesians of Anuta, a remote community in the Solomon Islands. It situates Anuta's reef map in relation to academic discussions of indigenous cartography and describes the process that resulted in the map's physical representation.     

Relief and Colour

Abstract

Most maps which depict the earth's relief do not convey information about the colour or texture of the earth's surface. Ways of embodying these additional elements into hill-shaded maps are proposed by the Senior Lecturer in Geodesy, Israel Institute of Technology (Technion).     

A NOTE ON CLARKE'S FORMULAE

Abstract

An elegant proof of Clarke's Formulae for lines of medium length has been given by G. T. McCaw. It is based on the properties of polar triangles in spherical trigonometry, and on the application of Legendre's Theorem.     

Ptolemy and the Early Image of the Old World

Abstract

A cartographic symposium held at Ulm in November 1982 was stimulated by the 500th anniversary of the printing of Ptolemy's 'Geographica' in that city, and was attended by an international gathering of historical cartographers.     

MODIS V006和V005全球反照率产品精度对比分析

反照率作为一种非常重要的地表能量平衡、全球变化研究的参数,在众多研究领域中得到了广泛的应用,到目前为止已经有多种全球范围的反照率产品进行业务化生产和发布,针对不同反照率产品质量评价的研究也变得愈加重要。MODLAND团队在MODIS V005反照率产品反演算法的基础上通过改进16天周期内观测数据加权的方法生产出新版本的反照率产品MODIS V006。本文针对MODIS两个版本V005及V006的反照率产品,利用FLUXNET地面站点数据,比较验证两个版本反照率的总体精度以及在不同地表类型条件下的精度差异,同时通过交叉验证的方法分析二者的差异及稳定性。验证结果表明,MODIS V006反照率产品虽然在全反演高质量的数据比例上较V005有所下降,但是在同等条件下V006在提高时间分辨率的同时其精度也有所提高,在不同的地表类型条件下精度也优于V005,且在时间序列分布上具有稳定比例的高质量数据,可以满足大多数应用的精度需求。     

The Land Map and Air Chart at 1:250,000

Abstract

This new double series, commonly known under its combined title, 'Joint Operations Graphic' (JOG), is an ambitious attempt to create a new map series of world-wide coverage, suitable in its alternative forms for both ground and air operations. Conflicts of requirement between services, and between allied mapping agencies, inevitably make this an extremely difficult problem. The task is systematically analysed with regard to planning, specification, production methods and problems, and product evaluation. The accompanying printed map specimen has been provided by courtesy of Survey Production Centre. The paper was first given at the Symposium of the British Cartographic Society, Newcastle upon Tyne, September 1967.     

Using Low‐Resolution Satellite Data to Quantify Terrestrial Carbon in Tropical Areas

Abstract

The ability to map and monitor terrestrial carbon is important in tropical regions where land conversion is intense and tropical moist forests store much of Earth's terrestrial carbon. The release of terrestrial carbon in the form of carbon dioxide could alter local, regional, and global weather, and enhance the greenhouse effect. This study analyzed the ability of coarse‐resolution Advanced Very High Resolution Radiometer (AVHRR) remote sensor data to quantify carbon stored in the Guaporé / Itenez River Basin in Bolivia and Brazil. This area was selected because of the amount of land conversion that has occurred there relative to other areas of the Amazon Basin. A supervised vegetation classification map was created with training sites acquired through fieldwork done in the area in summer 1998. Image pixels were classified as tropical moist forest, degraded tropical moist forest, cerrado, grasslands, degraded savanna, or bare ground. Estimated above and below‐ground carbon values of the different land cover types were applied to each class to calculate total carbon values. It was concluded that data such as AVHRR may be used to calculate the amount of carbon in terrestrial ecosystems in regional scale areas.