ALBERT

Notes: This paper assesses the feasibility of estimating water levels using digital photogrammetry. A common problem during an extreme flood event is that automated water level recorders do not record the highest water levels, as a result of instrument malfunctioning. This paper explores two possible solutions to this problem based upon data acquired using synoptic remote sensing methods. The first method requires: (a) high-resolution elevation data (for example, in the form of a digital elevation model for the floodplain); and (b) information on the planimetric position of the maximum flood extent, such as from debris lines (known as wrack lines) visible on aerial imagery flown after the event. The planimetric data can then be used to segment the topographic data in order to identify water level elevations. The second method uses a digitial photogrammetric approach and is suitable where no topographic data are available, but aerial imagery is available, flown after the event. Provided this imagery is of the right scale, digital photogrammetric analysis may be used to identify the elevations of wrack lines visible on the imagery. In this paper, the second of these options is compared with the first. The research shows that desktop photogrammetric methods, using 1:4500 scale imagery, can yield water level estimates that are precise to ±0·147 m, on the basis of check data obtained from lidar data. This is a worst possible estimate of the acquired precision given uncertainties in the lidar data. When compared with the first option, based upon segmenting lidar data using flood outlines, the photogrammetric approach was found to be preferable given both the quality of the lidar and uncertainties over how to segment it.

Notes: Aerial photography for archaeology has been developing its approaches and techniques over the past 100 years so that it now integrates the results of reconnaissance with extensive interpretative and analytical surveys. This paper introduces the philosophy and approach of the English Heritage (EH) Aerial Survey team, covering aerial reconnaissance and the National Mapping Programme (NMP), as well as the potential developments and opportunities in Europe. In the 1980s there was a debate over the nature of the evidence derived from aerial photographs, especially how to describe archaeological features. As part of NMP a classification and recording system has been devised which meets most of the users’ needs, be they national organisations, county archaeologists, commercial contractors or university-based researchers. The maps and records produced by NMP are used to further our understanding of the past human settlement in England, not only at the individual site level, but also in regional or landscape contexts. This paper provides an overview of the current progress of NMP and acts as an entrée for explaining the current research and recording of archaeological landscapes throughout Europe. Recent developments in Britain and Europe have provided the opportunity for a greater priority to be given to aerial survey and accelerating programmes of mapping. In Europe the ending of the cold war has allowed greater access to aerial photographs and the possibility of beginning new reconnaissance, as well as introducing new forms of remote sensing. All these developments have led to a transformation of our understanding of prehistoric, Roman and medieval archaeology.

Notes: This paper revisits the basic mathematical formulation of ortho-image (digital orthophoto) generation. The main objective is to provide an approach for predicting the accuracy of an ortho-image, according to the accuracy of the digital elevation model (DEM), control points and image measurements, the configuration of fiducial, tie and control points, and the ground slope. The approach is based on applying the well-known law of error propagation to the mathematical model of ortho-image generation. Although it may seem intuitive for professionals in the field of photogrammetry, such an approach is essential in the era when specialists in other fields use off-the-shelf software packages for ortho-image generation. Simulations with the derived approach show that the accuracy of the ortho-image is more sensitive to errors in image measurement of fiducial, tie and control points and ground coordinates of control points, than to DEM errors. Non-standard configurations of fiducial, tie and control points further impair the accuracy. In addition, certain combinations of point location and ground slope might lead to unacceptably large error on the ortho-image.

Notes: The attempts by A. S. Macdonald in the late 1980s and by J. A. Allan in the mid-1990s to integrate the UK societies and professional organisations within the spatial science field are described. The Photogrammetric Society, noting a long-term decline in its membership, set up an internal working group in 1997 to consider the future of the Society. A lengthy questionnaire to all individual members produced a 57% response and mandatory support for renewed action on greater inter-society cooperation.A further effort to produce a wide amalgamation of bodies in the UK spatial science field on the Macdonald/Allan models failed for lack of support nationally. As a smaller step, perhaps to be extended later, a merger with the Remote Sensing Society was eventually agreed. The subsequent lengthy and delicate negotiations necessary to bring about a successful merger between these two mature, independently minded learned societies are described. The two societies were formally merged on 1st April 2001.The author was a member of both the Photogrammetric and the Remote Sensing Societies and chaired the External Affairs Committee of the Photogrammetric Society preceding the merger.

Notes: This paper presents the prototype of a low-cost terrestrial mobile mapping system (MMS) composed of a van, two digital video cameras, two GPS receivers, a notebook computer, and a sound frame synchronisation system. The imaging sensors are mounted as a stereo video camera on top of the vehicle together with the GPS antennae. The GPS receivers and the notebook computer are configured to record data referred to the vehicle position at a planned time interval. This position is subsequently transferred to the road images. This set of equipment and methods provide the opportunity to merge distinct techniques to make topographic maps and also to build georeferenced road image databases. Both vector maps and raster image databases, when integrated appropriately, can give spatial researchers and engineers a new technique whose application may realise better planning and analysis related to the road environment. The experimental results proved that the MMS developed at the São Paulo State University is an effective approach to inspecting road pavements, to map road marks and traffic signs, electric power poles, telephone booths, drain pipes, and many other applications important to people's safety and welfare. A small number of road images have already been captured by the prototype as a consequence of its application in distinct projects. An efficient organisation of those images and the prompt access to them justify the need for building a georeferenced image database. By expanding it, both at the hardware and software levels, it is possible for engineers to analyse the entire road environment on their office computers.

Notes: Lidar and photogrammetry have both been evaluated for detecting shortterm coastal change using the Black Ven mudslide, Dorset as a case study. A lidar-generated digital elevation model (DEM) was obtained and initially compared with a DEM generated using available 1:7500 scale aerial photography and automated digital photogrammetry. The quality of these two data sets was assessed using a third DEM, derived using a total station and conventional ground survey methods. The vertical accuracies (rms error) of the lidar and photogrammetry were 0.26m and 0.43m respectively, although both data sets displayed a tendency to generate heights slightly lower than the elevation of the terrain surface. The quality of the two data sets was then assessed with respect to local slope angle. The accuracy of photogrammetrically derived elevations varied with slope and more so than in the case of lidarFrom these basic tests, lidar has proved to be more accurate than photogrammetry for soft-cliff. monitoring. Further research is required to establish whether this trend is applicable to other data sets and specifically for photogrammetric data acquired using larger scale imagery

Notes: An understanding of the evolution of cracks in concrete structures due to long term natural deformation is important to civil engineers, but quantitative measurements can be difficult to make. However, digital imaging offers a potential solution. This short paper illustrates the operational application of automated image processing techniques for accurate, multi-temporal crack measurements. The first part of this paper provides an overview of automatic feature extraction, essential for automatic crack detection. The latter part describes the methods developed for detecting and measuring cracks. Due to the long term nature of the application, operational results have yet to be finalised, although sample results are presented

Notes: This paper gives the results of an investigation into the use of different sampling rates and models for the interpolation of perspective-centre coordinates in GPS-assisted aerial triangulation. Industry-standard models and rigorous signal reconstruction filtering have been implemented for two largescale photogrammetric blocks. GPS sampling rate was found to have the most impact on bundle adjustment results in terms of the perspective-centre residuals. However, the accuracy of object-space point coordinates was found to be invariant to both GPS sampling rate and interpolation method

Notes: Books reviewed:S. Openshaw and R. J. Abrahart, GeocomputationM. Craglia and H. Onsrud, Geographic Information Research: Transatlantic PerspectivesP. J. Halls, Spatial Information and the EnvironmentJ. Sievers and T. Schneider, Second International Symposium on Geographical Names: Geonames 2000J. C. Leachtenauer and R. G. Driggers, Surveillance and Reconnaissance Imaging Systems: Modelling and Performance PredictionP. A. Longley, M. F. Goodchild, D. J. Maguire and D. W. Rhind, Geographic Information Systems and ScienceY. Q. Chen and Y. C. Lee, Geographical Data AcquisitionK. Borre, Plane Networks and their Applications.A. Hirschfield and K. Bowers, Mapping and Analysing Crime Data: Lessons from Research and PracticeO. Koelbl, Proceedings of the Oeepe Workshop on Automation in Digital Photogrammetric ProductionRICS Books, Vertical Aerial Photography and Derived Digital Imagery: Client Specification GuidelinesD. E. Reeve and J. R. Petch, Gis Organisations and People: A Socio-Technical Approach

Notes: Earth observation satellites with 1m resolution, such as Space Imaging's Ikonos system, offer the photogrammetric and remote sensing communities a significant new means for geospatial information collection. These satellites possess the potential for pixel-level geopositioning precision and promise timely, highly automated generation of two dimensional (2D) and three dimensional (3D) spatial information products. This paper concentrates on the pursuit of optimal accuracy and considers an essential first step in the evaluation of the Ikonos imaging system, namely the metric integrity of the sensor system. In the absence of sensor calibration information (the camera model), an empirical evaluation approach has been adopted. This involves an assessment of 2D transformations between image and planar object space. It is shown that based on results obtained in the Melbourne Ikonos Testfield, 2D geopositioning to 0.5 m accuracy is possible from the base-level “Geo”product when a modest amount of good quality ground control is available and sub-pixel image mensuration is achieved. These findings are applicable to both near-nadir imagery and oblique stereo images. Moreover, the results obtained suggest that there are no significant geometric perturbations in the sensor system and initial image processing, which augurs well for the successful application of non-collinearity based 3D orientation and triangulation models for Ikonos imagery.

Notes: Many photogrammetric and GIS applications, such as city modelling, change detection and object recognition, deal with surfaces. Change detection involves looking for differences between two surface models that are obtained from different sensors, for example an optical sensor and a laser scanner, or by the same sensor at different epochs. Surfaces obtained through a sampling process may also have to be compared for future processing (for example transformation parameter estimation and change detection). Surface matching is therefore an essential task in these applications. The matching of surfaces involves two steps. The first step deals with finding the correspondences between two surface points and/or patches. The second step requires the determination of transformation parameters between the two surfaces. However, since most surfaces consist of randomly distributed discrete points and may have different reference systems, finding the correspondences cannot be achieved without knowing the transformation parameters between the two surfaces. Conversely, deriving the transformation parameters requires the knowledge of the correspondence between the two point sets. The suggested approach for surface matching deals with randomly distributed data sets without the need for error prone interpolation and requires no point-to-point correspondence between the two surfaces under consideration. This research simultaneously solves for the correspondence and the transformation parameters using a Modified Iterated Hough Transform for robust parameter estimation. Several experiments are conducted to prove the feasibility and the robustness of the suggested approach, even when a high percentage of change exists.

Notes: It is well recognised that data volume represents a huge overhead for softcopy photogrammetry. For example, a file size of 100 Mbytes will be generated from a black and white aerial photograph if digitised with a resolution of 20μm. Large data volumes not only create storage problems but also affect the speed of image processing. As a consequence, data compression of image data is a matter of great significance. This paper describes an investigation into the effects of image compression on the accuracy of digital terrain models (DTMs) extracted from the compressed images. The JPEG system implemented in the Z/I Imaging ImageStation digital photogrammetric workstation (DPW) was used in the study. A systematic test has been carried out on the effect of different levels of JPEG compression (with Q-factors from 1 to 100) on the resulting DTM, which is automatically generated by the DPW using Match-T software. An analysis of the results from the two sites tested shows that image compression tends to cause more significant degradation when the image texture is richer, but that recommendations on Q-factors for use with the ImageStation appear to err on the side of caution. This analysis leads to some tentative conclusions and recommendations both for future investigation and for photogrammetric practice.

Notes: This paper describes an approach to single image automatic orientation and point determination by using current ortho-images and a DTM, and the experience gained in its implementation. The procedure proposed automatically extracts and matches feature points in evenly distributed patches on aerial images and ortho-images. A large number of image measurements (up to several thousand) are obtained in this process and are included in a robust space resection to determine the orientation parameters of the aerial image. For point determination with a single image, a method is formalised which integrates the DTM interpolation into the space resection so that the 3D ground coordinates of the image points can be determined in a unified mathematical model. Tests and analyses of this method show that the large number of automatic image measurements relieves the requirement for complicated and precise feature extraction and matching methods. The ground points obtained from single image intersection have an accuracy of approximately 1 pixel in planimetry, which fulfils the requirement for ortho-image updating. The elevation accuracy is mainly dependent on the quality of the current DTM and the interpolation method applied to it.

Notes: A critical problem in hydraulics research is accurate measurement of fluvially worked sediments, both in the field and in scaled representations of field situations in laboratory flumes. Such measurement must provide information on individual grain characteristics, and their organisation into structures referred to as bedforms. Existing measurement approaches are based upon mechanical or laser profiling devices, which are both expensive and take considerable time to acquire data, particularly where information is required at very high densities. This paper demonstrates how conventional automated terrain model extraction software, combined with image acquisition using a Kodak DCS460 digital camera, has been effective in generating digital elevation models of complex bed morphology. This has reduced time spent collecting data in the flume and has allowed data collection at much higher spatial and temporal densities. Application of the method is illustrated by research carried out at Hydraulics Research Wallingford. Issues discussed include configuration of photographs and control coordinates; appropriate camera calibration methods; stability of inner orientation of the Kodak DCS460; and accuracies obtained. Comparisons with independent check data reveal that accuracies of ±2.5mm have been achieved using a camera-to-object distance of 4.2 m.

Notes: Motion capture systems based on photogrammetric principles have gained wider use over recent years for applications ranging from clinical gait analysis to the creation of character animation for video games and the motion picture industry. Fast and robust determination of target trajectories is of crucial importance to the provision of optimal performance in the recovery of motion analysis parameters via multi-camera, real-time videometric systems. In this paper, the target path generation sequence is discussed, followed by an account of the formulation of a kinematic model based on the alpha-beta-gamma filter/predictor. A brief description of the photogrammetric feature correspondence determination follows, together with an account of the 2D and 3D marker tracking procedures that were adopted. Finally, initial experimental test results are summarised. These results indicate that the methods developed can provide robust performance and an operational speed which is fast enough to allow real-time 3D target tracking at standard video frame rates and beyond.

Notes: For the conservation of historic monuments, there may be considerable value in automating the methods of detection and analysis of surface condition and deterioration. This paper describes tests using a range of multiband and multispectral images for the assessment of architectural façade cover by means of supervised image classifications. From the spectral training sets, both pairwise distances (the Euclidean distance and the Jeffries-Matusita (J-M) distance) are calculated and are used to predict the a posteriori accuracy of image classification. Furthermore, the effects of increasing the number of spectral bands (blue, green, red and near-infrared) in the supervised maximum-likelihood classification procedures are also analysed, as are the benefits of applying principal components. The resultant multiband datasets increased both the J-M distance and the classification accuracy of the architectural façade, and thus enabled better identification and recognition of the different kinds of façade-cover features.

Notes: Automatic surface reconstruction by means of digital image matching essentially involves computation in both image and object spaces. In image space, image matching is performed according to certain radiometric and geometric similarity criteria for conjugate point determination. The matching operations may therefore be regarded as decision–making processes. In practice, however, the similarity criteria for conjugate point determination demonstrate non–deterministic behaviour. Thus, the nature of these decision–making processes is more compatible with fuzzy reasoning concepts. In object space, on the other hand, surface reconstruction procedures, which operate on the basis of previously determined conjugate points, are essentially deterministic in nature and hence demand rigorous geometric modelling. In this paper, a new approach for automatic surface modelling is proposed, based on two different mathematical treatments: a fuzzy logic reasoning method for the conjugate point determination in image space; and a robust finite elements approach for the surface modelling in object space. Tests carried out on real data demonstrate the high potential of the strategy proposed.

Notes: Book Reviwed in this article:PHOTOGRAMMETRIC WEEK ‘01. Edited by D. Fritsch and R. Spiller. WichmannPRACTICAL APPLICATIONS OF GIS FOR ARCHAEOLOGISTS: A PREDICTIVE MODELLING KIT. Edited by K. L. Westcott and R. J. Brandon.MANUAL OF GEOSPATIAL SCIENCE AND TECHNOLOGY. Edited by J. D. Bossler.WITH COMPASS AND CHAIN: EARLY AMERICAN SURVEYORS AND THEIR NSTRUMENTS. By S. A. Bedini.NEGLIGENCE IN VALUATIONS AND SURVEYS. By J. Murdoch.GEOGRAPHIC DATA MINING AND KNOWLEDGE DISCOVERY. Edited by H. J. Miller and J. Han.AUTOMATIC GENERALISATION PROJECT: LEARNING PROCESS FROM INTERACTIVE GENERALISATION. Report bu A. Ruas.REMOTE SENSING AND URBAN ANALYSIS. GISDATA 9. By J. -P. Donnay. M. J. Barnsley and P. A. Longley.VIRTUAL REALITY IN GEOGRAPHY. Edited by P. Fisher and D. Unwin.CLASSIFICATION METHODS FOR REMOTELY SENSED DATA. By B. Tso and P. M. Mather.AUTOMATIC EXTRACTION OF MAN-MADE OBJECTS FROM AERIAL AND SPACE IMAGES (III). Edited by E. P. Gruen and L. van Gool.CALIBRATION AND ORIENTATION OF CAMERAS IN COMPUTER VISION. Edited by A. Gruen and T. S. Huang.WORKSHOP ON AIRBORNE LASERSCANNING AND INTERFEROMETRIC SAR FOR DETAILED DIGITAL ELEVATION MODELS. Edited by K. TorilegÅrd and J. Nelson.GEOGRAPHIC INFORMATION SYSTEMS FOR GROUP DECISION MAKING. By P. Jankowski and T. Nyerges.MODELLING SCALE IN GEOGRAPHICAL INFORMATION SCIENCE. Edited by N. J. Tale and P. M. Atkinson.DIGITAL PHOTOGRAMMETRY. Edited by M. Kasser and Y. Egels.

Notes: Increasing interest is being expressed in the use of virtual cities for many fields of application, ranging from planning and simulation to business, advertising and the games industry. Currently, the extraction of buildings from imagery is costly. However, recent developments in digital photogrammetry aim to produce more rapid and efficient methods of modelling three dimensional objects in urban environments. This paper presents a semi-automatic system for the extraction of buildings from digital aerial imagery with the aid of volumetric primitives. The user is supported by automated tools, for example matching tools, in order to reach the necessary efficiency. With an extraction time of about 20 s per building primitive, this method is competitive in terms of the performance of classical photogrammetric procedures, and also offers additional features for analysis, texture mapping and Internet applications.

Notes: Market needs for airborne and spaceborne imagery used in photogrammetry and GIS applications are changing. Fundamental changes in sensors, platforms and applications are currently taking place. Most recently, new high resolution spaceborne sensors have become available. Besides classical photogrammetry, new thematic applications will drive the future image market. Savings in cost and time, together with the need for higher and reproducible radiometric resolution or spectral information will push forward the change from analogue to digital imagery. High resolution satellites will compete with airborne film-based photography and digital camera systems.With the availability of a digital airborne camera, it is possible to completely close the digital chain from image acquisition to exploitation and data distribution. The key decision regarding the camera design in this case is whether a linear or area array sensor should be used. In view of the high geometric accuracy requirements in photogrammetry, Z/I Imaging has focused development on a digital camera based on an area sensor. An essential aspect of this decision was not only the aerial camera system, but also the entire photogrammetric process to the finished photographic or mapping product. If this point of view is adopted, it becomes clear that the development of a digital camera involves more than simply exchanging film for silicon. Aspects such as data transfer rates, in-flight data processing and storage, image archiving, georeferencing, colour fusion, calibration and preprocessing have the same influence on the economic assessment of a digital camera system. This paper describes current development activities and application aspects of a digital modular airborne camera system.

Notes: This paper seeks to review the progress that is being achieved by fluvial geomorphologists in making use of digital photogrammetry for river channel research. Fluvial geomorphology is first placed in a basic historical context from which the failure to make full use of the potential of photogrammetry is noted. A review is then given of the ways in which fluvial geomorphologists are now making use of photogrammetry, recognizing that the development of digital approaches has both made photogrammetry a more cost-effective tool and also introduced a range of new research questions. The main objective of this paper is to demonstrate the importance of these questions and to illustrate some of the ways in which they are being addressed. Special attention is given to the issue of data quality, which is frequently (and perhaps conveniently) ignored.

Notes: The automatic interpretation of aerial and satellite imagery by means of image analysis is currently one of the major research tasks in photogrammetry and related disciplines. The primary goal is the automatic extraction of visible, spatial topographic objects from imagery. The extracted objects represent one possible form of input for creating geographic databases. In this paper, different aspects of image analysis are discussed and a framework is provided for scene interpretation, which is based on the integration of image analysis and a GIS data model. Two examples concerned with the combined extraction of roads and trees, and with the multitemporal interpretation and monitoring of moorland, are given to illustrate the research.

Notes: Topographic information from maps and geographical information systems (GIS) has been combined with satellite data (SPOT Panchromatic, SPOT Multispectral and Landsat Thematic Mapper) to derive a product that may be valuable in preliminary route location studies. The objectives of this study were to evaluate the classification accuracy of this combined product, to compare levels of ground detail obtainable from different types of satellite imagery against aerial photography, and to present an example application on the use of the combined product.The classification accuracy of the combined product was dependent on the type of land cover and was 83 to 100 per cent successful, with accuracy exceeding 95 per cent for most land cover types. The overall accuracy of the product was almost 95 per cent, with accuracy based on KHAT statistics of 92 per cent. Varying levels of ground detail were attainable from different types of satellite imagery. This detail may be adequate for preliminary route selection, especially in the absence of aerial photographs and GIS. The combined product presented in this study was applied successfully in selecting the optimal route for the Greater Amman ring road.

Notes: Investigation of the influence of data compression techniques on the quality and further processing of satellite sensor imagery is a research and development topic which remains both current and important. In principle, this extends the scope of data compression in remote sensing beyond the classical applications of data transmission and storage. Against this background, the main objective of this study is to examine the effect of data compression on the automatic classification of Landsat imagery. The main focus of this is on the built environment. In order to obtain better segmentation results, the feature base is expanded to include both spectral features, such as spectral signature and texture, and non-spectral features such as shape, structure and topology. This expansion enables the integration of context information into the feature extraction process. The image is systematically compressed (channel by channel) at compression rates ranging from 5 to 100 using wavelet-based software. An integrated, pixel-based classification approach is then used to segment the compressed imagery. The analysis of the results obtained indicates that a compression rate of up to 20 can conveniently be used without adversely affecting the segmentation results. The suitability of wavelet compression schemes for the compression of heterogeneous data is also underlined.

Notes: The graphical representation and interactive manipulation of accurate three dimensional (3D) models of reality is rapidly becoming an inescapable necessity for many applications of geographical information systems (GIS). There are many problems and difficulties that must be overcome in order to facilitate such 3D models. Can accurate measurements, at sufficient resolution and using affordable resources, be obtained? Will application software usefully process, in all aspects, models of the real world, held in full 3D? Can a topology of containment, adjacency and contiguity in 3D be integrated into the conventional procedural and recording functionality of two dimensional (2D) GIS and still provide workable spatial analysis tools? A 3D GIS applied to an urban environment should maintain a model that would typically consist of solid representations of individual buildings, roads and utilities, providing both external and internal detail, all assigned to a suitable digital terrain model (DTM).The particular 3D application considered here addresses the need for accurate reconstruction of historical urban buildings. The creation, manipulation and exploration of such models is often referred to as “virtual heritage”. Much of this paper describes an effective methodology, called the Phoenix algorithm, requiring only a single image of an urban object, for the construction of 3D models of buildings at high resolution. The development of this algorithm is discussed and the results obtained from it are compared with those obtained using traditional 3D capture techniques. An outline of further potential GIS applications is presented.

Notes: Object recognition and image understanding have increasingly become major subjects of interest for research activity in digital photogrammetry. This paper provides an overview of object recognition in photogrammetry, beginning with a problem statement and brief paradigm description. In order to exemplify the concept, automatic interior orientation is presented as an object recognition problem. Subsequent sections discuss the current status of object recognition by identifying relevant criteria, such as modelling, system strategies and inference components. Such criteria are useful for comparing object recognition systems or proposed approaches. Strengths and weaknesses of current systems are summarized, followed by a more detailed analysis of the modelling problem. Finally, two new approaches (scale-space and fusion of multisensor/multispectral data) are mentioned. These approaches serve as examples of promising new trends which have the potential of advancing object recognition to a new level.

Notes: Information loss is caused when a surface is sampled with a finite interval, such as in the production of a digital elevation model (DEM). This information loss can become the dominant part of the error in a DEM. The ability to quantify information loss enables guidance to be provided for an appropriate choice of grid interval and better accuracy assessment for the DEM. With the use of digital photogrammetric systems, evaluation of information loss has become much easier. This paper describes three methods of evaluating information loss. An example is given of the method which is most appropriate for use with a digital photogrammetric system, based on rock cliff surface data and the VirtuoZo system.

Notes: Book review in this ArticleGEOGRAPHICAL INFORMATION SYSTEMS AND THE LAW: MAPPING THE LEGAL FRONTIERS. By G. Cho. John Wiley & Sons Ltd., Chichester, 1998. ISBN 0 471 94857 8. 158 × 236 mm. xix + 337 pages. 19 figures and 7 tables. Price £70 hardback.UNDERSTANDING SYNTHETIC APERTURE RADAR IMAGES. By C. J. Oliver and S. Quegan. Artech House, Inc., Norwood, USA, 1998. ISBN 0 89006 850 X. 160 × 235 mm. xxvii + 479 pages. 125 diagrams and illustrations. Price £79 hardback.REMOTE SENSING OF TROPICAL REGIONS. By E. A. Sharkov. John Wiley & Sons Ltd., in association with Praxis Publishing Ltd., Chichester, 1998. ISBN 0 471 97171 5. 172 × 247 mm. xvii + 310 pages, plus 8 pages of colour plates. 78 figures and 24 tables. Price £65 hardback.ELEMENTS OF PHOTOGRAMMETRY, WITH APPLICATIONS IN GIS. By P. R. Wolf and B. A. Dewitt. McGraw Hill, New York, 2000. ISBN 0 07 292454 3. 160 × 235 mm. xiii + 608 pages. Illustrated. Price US$60 hardback.THE WESTERN FRONT FROM THE AIR. By N. Watkis. Sutton Publishing, Stroud, 1999. ISBN 0 7509 1338. 200 × 270 mm. ix + 130 pages. Illustrated. Price £20 hardback.ADVANCES IN REMOTE SENSING AND GIS ANALYSIS. Edited by P. M. Atkinson and N. J. Tate. John Wiley & Sons Ltd., Chichester, 1999. ISBN 0 471 98577 5. 174 × 251 mm. xiv + 273 pages, plus 4 pages of colour plates. Illustrated. Price £55 hardback.MANUAL OF REMOTE SENSING, THIRD EDITION, VOLUME 3. REMOTE SENSING FOR THE EARTH SCIENCES. Edited by A. N. Rencz. John Wiley & Sons Inc., New York, USA, in co-operation with the American Society for Photogrammetry and Remote Sensing, 1999. ISBN 0471 29405 5. 184 × 260mm. xvi + 707 pages. 280 illustrations and tables and 53 colour plates. Price £128 hardback.MANAGING NATURAL RESOURCES WITH GIS. By L. Lang. SERVING MAPS ON THE INTERNET. By C. Harder. Environmental Systems Research Institute Inc., Redlands, California, USA, 1998. ISBN 1 879102 53 6 and ISBN 1 879102 52 8, respectively. Both 229 × 189 mm. ix + 117 pages and ix + 130 pages, respectively, both plus CD-ROM. Illustrated. Price US$19.95 each, paperback.PASSIVE MICROWAVE REMOTE SENSING OF OCEANS. By I. V. Cherny and V. Yu Raizer. John Wiley & Sons Ltd., in association with Praxis Publishing Ltd., Chichester, 1998. ISBN 0 471 97170 7. 172 × 247mm. viii + 195 pages. 127 illustrations, including 8 pages of colour plates. Price £55 hardback.VIDEO CAMERA TECHNOLOGY. By A. C. Luther. Artech House Inc., Norwood, USA, 1998. ISBN 0 89006 556 X. 160 × 235 mm. xvi + 312 pages. Black and white illustrations. Price £59 hardback.DIGITAL PHOTOGRAMMETRY, VOLUME I. By T. Schenk. TerraScience, Laurelville, U.S.A, 1999. ISBN 0 9677653 0 7 perfect bound; ISBN 0 9677653 1 5 case bound. 235 × 162mm. xx + 421 pages. 179 figures and 15 tables. Price US$49 perfect bound, US$69 case bound, plus package and postage.INFINITE PERSPECTIVES: TWO THOUSAND YEARS OF THREE-DIMENSIONAL MAP-MAKING. By B. M. Ambroziak and J. R. Ambroziak, with an introduction by R. Bradbury. Princeton Architectural Press, New York, 1999. ISBN 1 56898 195 3. 382 × 325mm. 111 pages. 100 colour illustrations. Price £55 hardback.EVEREST—THE MAN AND THE MOUNTAIN. By J. R. Smith. Whittles Publishing, Caithness, 1999. ISBN 1 870325 72 9. 170 × 240mm. xiv + 306 pages. 45 figures and 5 appendices. Price £37.50 paperback.TEXT BOOKS ON REMOTE SENSING AND GIS. Remote Sensing Notes edited by Japan Association of Remote Sensing. GIS Notes by S. Murai. Asian Center for Research on Remote Sensing, Thailand, 1999. 140 × 130mm. Price unknown, CD-ROM.REMOTE SENSING CHANGE DETECTION. Edited by R. S. Lunetta and C. D. Elvidge. Ann Arbor Press, Michigan, USA, 1998. ISBN 1 57504 037 9. 183 × 260mm. xviii + 318 pages. 20 colour plates, plus numerous illustrations. Price US$69.95 hardback.NORFOLK FROM THE AIR. VOLUME 2. Edited by P. Wade-Martins. Photography by D. Edwards. Norfolk Museums Service, Norwich, 1999. ISBN 0 903101 68 8. 212 × 284mm. 148 pages. 135 half page aerial photographs, 89 in black and white. Price £15.95 paperback.

Notes: As the performance of megapixel digital imaging systems continues to improve, the rapid growth of high-end consumer markets drives prices ever lower. When such cameras are married with emerging, desktop “photogrammetric” software packages, the close range photogrammetric community is faced with many new challenges and opportunities. The dramatic changes in the technological arena are matched by a rapidly changing business environment in which concepts such as “Partnering” and “Supply chain management” have become key themes. As organizations of all sizes seek to thrive within this new business landscape, there appears to be a willingness to think more flexibly about the client-supplier relationship and the sharing of risks and rewards. This, in turn, has encouraged the development of highly customized measurement solutions across a wide range of market sectors. In each of these solutions the emphasis is not on a generic photogrammetric product, but on a highly tailored system tightly coupled to existing workflows, and focused on the specific needs of the client. Such systems pose particular challenges to their designers, since they are frequently operated by users with relatively little photogrammetric background and yet must always meet the challenging requirement of producing an output which is “fit for purpose”. Thus this paper hopes to show how novel megapixel imaging systems can be configured to deliver flexible measurement systems capable of millimetric level accuracy within the challenging engineering environments typical of the nuclear and process industries (hence the microsievert component of the title).

Notes: A method is presented which makes a valuable contribution to automation in close range metrology. Successful identification of textcoded measurement targets has three essential characteristics: (1) large and easily expandable code depth; (2) robustness with respect to radiometric and geometric influences; and (3) rejection capability in case of low identification quality. The proposed method of text recognition of target labels is based on experience which has been gradually accumulated in the context of automated document analysis at the DaimlerChrysler Research Center.

Notes: This paper is concerned with the application of automated digital photogrammetry, using 1:3000 scale photography, to complex, natural landform surfaces, of typical interest to geomorphologists. It assesses the quality of the results obtained using a relatively cheap and readily available area based stereomatching package, in terms of precision, accuracy and external reliability. Precision is investigated with reference to the confidence that can be placed in individual matches. Accuracy is evaluated using specially collected, independent datasets obtained from an area of complex topography in Glen Affric, Scotland. Data collection was stratified to areas of different surface roughness. External reliability is judged with respect to estimates of slope, a key parameter in geomorphological investigations. The results show that, whilst the effects of grid density and vegetation correction are the most important controls upon the accuracy and the external reliability of the photogrammetric results, collection parameters associated with the stereomatching process can also exert some control, particularly in areas of complex topography. It is impossible to generalize rules for choice of optimal collection parameters without careful consideration of the surface under investigation. Given that maximum grid densities are defined by the object space pixel resolution, the paper concludes that surface quality is largely governed by traditional controls upon photogrammetric data quality (camera calibration, base:distance ratio, ground control), combined with either scanning density or digital image resolution. However, over some surfaces, careful consideration has to be given to the effect of matching parameters.

Notes: Hierarchical approaches for automated photogrammetric surface measurement invariably employ image pyramids and image matching at multiple resolutions. Such an approach is also applicable in industrial photogrammetry where projected light patterns are used to provide texture on an otherwise texture-free surface. This paper describes a novel strategy for hierarchical surface measurement in which projected non-repeating target patterns are employed, rather than the lower-resolution levels of an image pyramid. Thus, although the final derived digital surface model is obtained by image matching, preliminary surface models which support the matching are obtained using the non-repeating patterns. These projected patterns allow a simplification of the triangulation phase since they offer the potential of a fast and unambiguous solution to the image point correspondence problem. Following an introduction to the non-repeating pattern strategy, integration of the approach into a multi-camera vision metrology system is described and some experimental measurements are summarized

Notes: Book review in this ArticleGIS DATA CONVERSION: STRATEGIES, TECHNIQUES AND MANAGEMENT. Edited by P. Hohl. Onword Press, Santa Fe, 1998. ISBN 1 56690 175 8. 180 × 228 mm. xiii + 416 pages. Illustrated. Price £33.95 paperback.GEOGRAPHICAL INFORMATION SYSTEMS FOR ECOLOGY: AN INTRODUCTION. By R. Wadsworth and J. Treweek. Addison Wesley Longman Ltd., Harlow, 1999. ISBN 0 582 24652 0. 156 × 234 mm. xiii + 184 pages. Four colour plates, appendix, references and index. Price £14.99 paperback.GENERATION OF DIGITAL ELEVATION MODELS THROUGH SPACEBORNE SAR INTERFEROMETRY. Remote Sensing Series, Volume 30. By D. Small. Remote Sensing Laboratories, Department of Geography, University of Zurich, 1998. 147 × 207 mm. xvi + 150 pages. 84 figures, including images, and 8 tables. Price SFr 40 paperback.TRIANGULATION. By P. Whitaker. Phoenix House, London, 1999. ISBN 1 816590 80 6. 140 × 200 mm. 272 pages. Price £12.99.OEEPE SURVEY ON 3D-CITY MODELS. By C. Fuchs, E. G$uulch and W. F$ourstner. PERFORMANCE OF TIE-POINT EXTRACTION IN AUTOMATIC AERIAL TRIANGULATION. By C. Heipke and K. Eder. OEEPE Official Publication No. 35. Bundesamt für Kartographie und Geodäsie, Frankfurt am Main, 1998. ISBN 3 88648 075 5. 175 × 245 mm. 198 pages. 42 figures, 27 tables and 7 appendices. Price DM47, paperback, plus DM7 for postage and packing and DM20 for foreign exchange charges, if applicable.EUROPEAN SPACE DIRECTORY. Fourteenth edition. Edited by D. Shirvanian. Sevig Press, Paris, 1999. ISSN 0765 0574. 210 × 270 mm. 316 pages. 1 figure and 30 tables. Price FFr990 (£150) paperback.CAMERA AT SEA. THE HISTORY OF THE ROYAL NAVAL PHOTOGRAPHIC BRANCH, 1919–1998. By N. Mercer. Airlife Publishing Ltd., Shrewsbury, 1999. ISBN 1 85310 889 8. 218 × 306 mm. 144 pages, including a 72 page portfolio of colour plates. Price £24.95 hardback.ESSENTIAL DARKROOM TECHNIQUES. Third edition. By J. Eastland. Cassell, London, 1999. ISBN 0 304 35086 9. 190 × 247 mm. 208 pages. 144 figures and 22 tables. Price £18.99 paperback.ADVANCES IN MOBILE INFORMATION SYSTEMS. (MOBILE COMMUNICATIONS SERIES.) Edited by J. Walker. Artech House, Inc., Norwood, USA, 1999. ISBN 0 89006 951 4. 159 × 235 mm. xxi + 468 pages. 104 figures and 42 tables. Price £67 hardback.

Notes: In the period after the First World War the Ordnance Survey was relatively slow to recognise the contribution that air survey could make to its work. In part, this was due to external constraints on budgets, which helped to stifle innovation. However, the views of the four Directors General, Close, Jack, Winterbotham and MacLeod, were to play large roles in determining the energy with which innovations were adopted. Both Close and Winterbotham were generally sceptical about the value of air survey, while Jack was well disposed, but constrained by budget limitations. In MacLeod, however, air survey was to find a convinced champion. This paper explores the roles played by the key players and how, in the late 1930s, significant advances were made.

Notes: Architecture at the Maya archaeological site of Uxmal in Yucatan, Mexico has been documented since the 17th century by historians, archaeologists, illustrators, photographers, and most recently photogrammetrists. This paper reviews the work of the major contributors to recording of architecture at Uxmal with a particular focus on the 19th century stereophotography of Alice and Augustus Le Plongeon who worked to record all the standing architecture at Uxmal, and the close range stereophotogrammetric projects that recorded the Adivino Pyramid during the late 20th century.

Notes: Urban area building extraction is one of the most challenging problems in photogrammetry. Well-extracted buildings are needed for a variety of applications, such as cartography, building GIS databases for cities, and urban planning. This paper presents a new technique to extract 3D building wire-frames using a robust multi-image line-matching algorithm. Although one pair of images is adequate to find the 3D position of two visibly corresponding image features, it is not sufficient to solve the general building extraction problem due to obscured parts in the building. Four images are used in this research to extract the building wire-frames. First the images are segmented into regions. Regions are then classified into roof regions and non-roof regions based on their size, shape, and intensity values. The roof region boundary pixels are located and used to find the region perimeters. Region correspondence is solved in a pair-wise mode over all images using the epipolar constraint, region size, region shape, and region intensity values. Image lines within the corresponding regions are matched over all images simultaneously by first creating a plane for each region line. Planes are then intersected simultaneously and geometric consistency is used to determine acceptance or rejection. Results with high overlap and sidelap aerial images are presented and evaluated. The results show the completeness and accuracy that this method can provide for extracting complex urban buildings. The average coordinate accuracy is about 0·8 m using 1:4000 scale aerial photographs scanned at 30 μm. Six buildings were examined; the line detection rate is 98%.

Notes: Automatic digital elevation model (DEM) generation has become an established technique within mapping agencies. This paper assesses the effectiveness of automatic DEM generation using area-based matching for glaciated terrain in Antarctica. DEM accuracy is assessed by comparison with check data acquired using analytical photogrammetry and independent field measurements.An optimum DEM collection strategy is identified. DEM success is linked to ground terrain type and it is found that areas of a DEM which can be collected successfully are relatively insensitive to changes in the collection strategy. A method of isolating unsuccessful areas of a DEM for manual editing is tested for Antarctic terrain. In this example, over 90% success is achieved in identifying erroneous DEM results measured against check data.

Notes: The XIXth International Congress of Photogrammetry and Remote Sensing was held at the Amsterdam RAI International Exhibition and Congress Centre, the Netherlands, from 16th to 23rd July 2000. Reports are given on the Congress as a whole, including the General Assembly, some Technical Commission activities and the Congress Exhibition. Papers from the Congress are published in the International Archives of Photogrammetry and Remote Sensing, 33.

Notes: A scholarly account of the formative discussions, the founding and the first 20 years of the Photogrammetric Society was published in 1971 and republished in 1974. This present review concentrates on the latter years of the life of the Photogrammetric Society prior to its merger with the Remote Sensing Society in 2001.The authors joined the Photogrammetric Society in 1960 and were conspicuous in its affairs for many years. Although both occupied the Society's presidential chair, they also fulfilled several other roles in its efficient management. Atkinson's first contribution to the Photogrammetric Record was published in 1968 and Newton's in 1971.

Notes: Rapid urban development is achieved in some areas by the application of industrialized construction techniques. This approach creates extensive ‘‘regularised’’ urban areas, which are governed by a small set of building models. This paper describes a scheme for building rooftop extraction from aerial and high resolution satellite imagery that makes use of the characteristics of regularised urban areas. As the scheme is based on a bottom-up approach, emphasis is put on reducing the number of low-level features that should be considered during the polygon rooftop extraction. This is achieved with a set of geometric rules, which are defined based on the geometry of the building model. Experiments with real-world imagery show that this basis provides efficient filtering of the right-angle corners, thus improving the overall extraction performance.

Notes: Automated reconstruction of building objects from aerial images is a complex problem due to the diversity of buildings as well as noise and low contrast of images, which are the results of distant photography, atmospheric effects and poor illumination. In this paper, a semi-automated approach to the reconstruction of parametric building models from aerial images is presented, which works with line segments extracted from the image. The model is selected interactively from a library of parametric models. A perceptual grouping technique is used to select the most significant image lines in terms of relations such as proximity and parallelism. Model lines are searched for the same relations as in the grouped image lines, and the corresponding lines undergo a matching procedure, which determines whether or not a match can be found between the given model and image lines. An experiment with aerial images of flat-roof and gable-roof buildings is shown and its results indicate the robustness and efficiency of the proposed approach.

Notes: In recent years, collection and processing techniques for creating digital elevation models (DEMs; defined here as being surfaces composed of regular or irregular point data, without distinction) have advanced rapidly, allowing terrain to be represented with greater detail and accuracy. Accordingly, the amount of terrain data in existence proliferates as the resolution of sensors improves and acquisition costs lower. It is therefore becoming common for several models to cover any given area as higher accuracy or revised surveys are performed. Such coinciding data-sets allow improvement to the terrain depiction by integration techniques which merge and validate the individual DEMs. However, amalgamation of all available points is impractical, as errors and differences between the DEMs degrade the accuracy of the merged model, and the data volume may result in heavy oversampling. Consequently, this paper develops a DEM integration method by detailing the error budgets of individual and fused terrain models, then describing the merging procedure. Initially, comparison of the input surfaces is performed to isolate differences. Next, objects on the terrain surface are optionally removed before a surface matching algorithm is employed to detect and overcome systematic effects. Finally, the models are intelligently merged and the point distribution optimised to achieve an efficient surface representation. The methodology was used to integrate a dense airborne laser scanning DEM with sparser photogrammetric data encompassing a larger area. Surface matching proved to be vital, recovering a previously unidentifiable bias between the input DEMs, improving the accuracy of the fused surface.

Notes: Generally, a low-cost image-based motion study system consists of a set of two or more video imaging cameras and a set of object space control targets. The control targets are required to provide for the computation of exterior parameters of the video frames of objects in motion. Subsequently, the computed exterior orientation parameters are used to compute the position of the motion targets. In general, the accuracy of the motion data is dependent largely on the accuracy of the 3D coordinates of the control targets, the computed camera and lens parameters and the frame rate of the camera. Obviously, it is difficult to improve the frame rate of a low-cost camera; however, the other factors may be optimised analytically. Optimising the accuracy of the control targets is a straightforward process and is discussed briefly in the paper. Optimising the computed camera and lens parameters was the main focus of the research. Consequently, the paper provides the detail of the developed optimising technique. The results show that an optimal principal distance and other lens parameters can be determined by analysing the error of a set of highly accurate object distances. The evaluation shows that the accuracy of the video motion study system can be improved by as much as six times or a reduction of scaling error from 1·06 to 1·01.