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Titre : Das Relief der Urschweiz von Franz Ludwig Pfyffer (1716-1802) : 3D-Rekonstruktion, Analyse und Interpretation Titre original : [Le relief de la Suisse originelle de Franz Ludwig Pfyffer (1716-1802) : reconstruction 3D, analyse et interprétation] Type de document : Thèse/HDR Auteurs : Jana Niederöst, Auteur Editeur : Zurich : Institut für Geodäsie und Photogrammetrie IGP - ETH Année de publication : 2005 Collection : IGP Mitteilungen, ISSN 0252-9335 num. 089 Importance : 211 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-906467-56-6 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Photogrammétrie
[Termes IGN] analyse comparative
[Termes IGN] carte ancienne
[Termes IGN] carte en relief
[Termes IGN] dix-neuvième siècle
[Termes IGN] méthode de mesure
[Termes IGN] montagne
[Termes IGN] photogrammétrie analogique
[Termes IGN] photogrammétrie numérique
[Termes IGN] précision de localisation
[Termes IGN] précision des mesures
[Termes IGN] reconstruction 3D
[Termes IGN] SuisseIndex. décimale : 33.00 Photogrammétrie - généralités Résumé : (Auteur) The subject of this thesis is one of the most spectacular relief models in history, a large three-dimensional representation of Central Switzerland constructed by Franz Ludwig Pfyffer von Wyher (1716-1802). This masterpiece measures 6.7 m x 3.9 m and is on a scale of about 1: 11500. Pfyffer finished it in 1786 using his own measurements, which he took over a period of 40 years, decades before the first Swiss national triangulation system was established. In the eighteenth century, the relief was a novelty, offering observers a "virtual flight" over a mountainous region that was still unexplored at that time. Contemporary travel writers from all over Europe described their fascination with the model. However, with the appearance of new, more precise maps at the turn of the century, opinions on the topographic quality of the relief started to change: the model was considered merely as a piece of craftwork and was practically forgotten. The manifold possible implications of the relief - not only its topographic, but also its cultural, political, military and aesthetic aspects - have not yet been investigated.
Due to the scarcity of written documentation, this study is based on information derived from Pfyffer's topographic work. First, a precise true-scaled 3D computer model of Pfyffer's Relief was created with the help of photogrammetry and image processing procedures. Next, methods for the quantitative analysis of early cartographic works were developed. These methods were then applied to the computer model of Pfyffer's Relief and related maps of the region, so that new information regarding the process of the relief creation could be extracted. Finally, Pfyffer's achievement is compared with that of his contemporaries.
In order to produce a 3D computer model of Pfyffer's Relief, image-based object reconstruction techniques were applied. From a construction platform fixed at a height of 185 cm above the relief, two sets of images (analogue and digital) were taken, both providing stereo overlap for the whole object. As high accuracy was required and automated image-matching did not bring the expected performance, the phototriangulation and digital elevation model (DEM) measurements were carried out manually on an analytical plotter. The final product of the DEM generation was a regular raster with a grid width of 1 cm and an estimated accuracy of 0.78 mm. The analogue images were scanned at a high resolution, orthorectified and combined to form an orthomosaic. The orthomosaic was then superimposed on the DEM to produce an interactive photorealistic 3D model of the object, which could be used to help reconstruct the physical model in case of damage. The accuracy analysis described below was based on this computer model, as it is much easier and more effective to take measurements on the screen than directly from the complex relief surface.
In the second section of the thesis, fundamental methods for accuracy assessment of old maps and models are described in standard terminology and evaluated. There are only few publications dealing with this topic and those that exist merely analyse old maps: there are no such studies of three-dimensional works. The presented methods are based on a coordinate transformation between identical points in the analysed object and in the modem map. The main focus of this study -beyond the transformation of points - was to determine the metric parameters of a historical map or model. In particular, the 3D affine transformation should be noted. This is the first time that scales, rotation angles and shear values have been isolated and their significance analysed. A new approach for the whole process of accuracy analysis in early cartographic works was developed and implemented in a user-friendly software. The analysis starts with the preparation of input data and the definition of identical points. After the appropriate coordinate transformation, the map or model is georeferenced and a distortion grid is calculated. Finally, a new technique is used to determine the accuracy of polygonal map or relief features.
The third part of the thesis interprets the results achieved by the accuracy analysis. Based on ten of Pfyffer's letters to the famous Swiss scientist Micheli du Crest (1690-1766), Pfyffer's methods for angle, distance and height measurements were reconstructed. It can be concluded that he defined a mesh of large triangles, which he surveyed precisely by triangulation. He oriented his cartographic products using a compass. The orientation angle corresponds with the magnetic north pole, which differed from the geographic one by approximately 14.75 degrees at that time. Thus, the starting date of Pfyffer's surveying can be estimated as about 1747. The planar accuracy of both Pfyffer's Relief and two of his middle-scale maps is roughly 480 m (standard deviation in X- and Y-direction). It is most precise for the area around the city of Lucerne, whereas the geometric quality decreases in more distant regions. Pfyffer's principal instrument for measuring heights was the barometer. He chose Lake Luceme as a zero horizon for his height measurements and estimated its height above sea level with an excellent accuracy of 6 m. Other remarkable achievements include his height measurements in the Bernese Alps. Applying trigonometric measurements he succeeded in precisely determining the heights of the Eiger, MOnch, Jungfrau, Finsteraarhorn, Wetterhorn, Schreckhom and Gross Fieschhorn (height error < 20 m), thus solving one of the great scientific problems in the eighteenth century in Switzerland. Finally, the geodetic achievements of Kyffer were compared with state-of-the-art techniques in Europe at that time. It is shown that his work is comparable with the maps of other regions and countries. His major contribution to progress was systematic height measurement throughout a given area, which marked the start of a new era in cartographic height representation.Numéro de notice : 15144 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère En ligne : http://dx.doi.org/10.3929/ethz-a-005026536 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=55075 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 15144-01 33.00 Livre Centre de documentation Photogrammétrie - Lasergrammétrie Disponible Entwicklung einer automatisierten Konflikterkennung für partizipative GIS auf Basis dynamischer Ontologien / Manfred Loidold (2005)
Titre : Entwicklung einer automatisierten Konflikterkennung für partizipative GIS auf Basis dynamischer Ontologien Titre original : [Élaboration d'une méthode automatisée de résolution des conflits pour un SIG participatif sur la base d'une ontologie dynamique] Type de document : Thèse/HDR Auteurs : Manfred Loidold, Auteur Editeur : Zurich : Institut für Geodäsie und Photogrammetrie IGP - ETH Année de publication : 2005 Collection : IGP Mitteilungen, ISSN 0252-9335 num. 83 Importance : 196 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-906467-48-1 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Bases de données localisées
[Termes IGN] conflit
[Termes IGN] ontologie
[Termes IGN] résolution de problème
[Termes IGN] SIG participatifRésumé : (Auteur) The dissertation aims to support GIS-based planning processes by providing an automated conflict resolution method. The approach goes beyond the objectives of a useful and useable multi-user environment: The hypothesis of the approach states that the participants' interaction data contains knowledge about their intentions and cooperativeness, which is a basic requirement for a successful conflict resolution. The type of conflict is essential for developing a successful conflict solving strategy.
Social sciences distinguish between two types of conflict:
The conflict on distribution is characterised by an essential common value which is shared by all participants.
The conflict on values is caused by different, often contradictory values.
In contrary to conflicts on distribution, conflicts on values cannot be solved by negotiations because values are not negotiable.
Thus individual values are the key to conflict resolution. Values direct attitudes, which again result in characteristic activities. In case of a participatory planning process, these activities are acquired by the interaction data set. They enable us to draw conclusions about the particular attitudes and finally the underlying values. The more the schemes of activities are spread, the wider is the range of values and the more probable is the dominance of a conflict on values.
The analysis of the interaction data is based upon the concept of the intentional model by John F. Sowa describing the intentional influence of an interacting participant on the resulting modifications. In order to state the difference between the original data set and the modified results, the ontologies of spatial objects are described in their spatio-temporal dynamics and the geometric, topological, attributive and temporal components are analysed.
Thus, six criteria were conceptualised, formalised, and implemented, in order to analyse the participants' interactive behaviour patterns in relation to the following characteristic activities:
Spatial narrow-mindedness by the bounding box containing the interaction data.
Thematic narrow-mindedness by ratio of modified themes.
Thematic focus by the relative number of interactions concerning the specific object, which triggered and caused the participatory process (topic object).
Spatial focus by calculating the distance of the topic object to the geometric centre of the specific participant's interaction data.
Tendency to disputing by verifying, if repeatedly contradictory activities occurred, which are stereotype in their geometric, topological, attributive and temporal characteristics.
Tendency to prevent a partial compromise solution by adding protracting and irrelevant comments: ratio of this kind of comments.
As head of the participatory process the mediator weights the six criteria according to the observations during the process and decides which participant's interaction data set should by undergone the analytical procedure. The analytical functionality implemented in the prototype assigns the Cooperativeness Value (CV) to the selected participants:
Interpreted separately the CV indicates how cooperative the participant's behaviour during the interactive discussion session was.
By comparing the participants' CVs, the mediator gets evidence on the range of activities and attitudes, both correlating to the range of values. They indicate the type of conflict and outline these scenarios with the highest probability of successfulness.
In order to verify the correctness of the hypothesis, role plays were executed simulating participatory planning processes. The test persons knew the application of GIS in general but they were not familiar with the conceptual model of the approach. The tests confirmed the correctness of the approach: The system figured out those participants, whose task it was to act in an uncooperative way and to simulate contradictory values.Numéro de notice : 13287 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Thèse étrangère DOI : 10.3929/ethz-a-004906524 En ligne : http://dx.doi.org/10.3929/ethz-a-004906524 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54959 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 13287-01 37.10 Livre Centre de documentation Géomatique Disponible
Titre : Modelling of spaceborne linear array sensors Type de document : Thèse/HDR Auteurs : Daniela Poli, Auteur Editeur : Zurich : Institut für Geodäsie und Photogrammetrie IGP - ETH Année de publication : 2005 Collection : IGP Mitteilungen, ISSN 0252-9335 num. 85 Importance : 204 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-906467-50-4 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] auto-étalonnage
[Termes IGN] C (langage)
[Termes IGN] capteur aérien
[Termes IGN] capteur en peigne
[Termes IGN] capteur spatial
[Termes IGN] chambre DTC
[Termes IGN] compensation par faisceaux
[Termes IGN] géométrie de l'image
[Termes IGN] géoréférencement direct
[Termes IGN] géoréférencement indirect
[Termes IGN] GPS-INS
[Termes IGN] image EROS
[Termes IGN] image MOMS-2P
[Termes IGN] image SPOT-HRS
[Termes IGN] image Terra-ASTER
[Termes IGN] image Terra-MISR
[Termes IGN] modèle géométrique de prise de vue
[Termes IGN] modèle mathématique
[Termes IGN] modèle par fonctions rationnelles
[Termes IGN] modèle stéréoscopique
[Termes IGN] orientation du capteur
[Termes IGN] orientation externe
[Termes IGN] orientation interne
[Termes IGN] point d'appui
[Termes IGN] point de vérification
[Termes IGN] points homologuesIndex. décimale : 35.11 Géométrie et qualité des prises de vues Résumé : (Auteur) The topic of this research is the development of a mathematical model for the georeferencing of imagery acquired by multi-line CCD array sensors, carried on air- or spacecraft. Linear array sensors are digital optical cameras widely used for the acquisition of panchromatic and multispectral images in pushbroom mode with spatial resolution ranging from few centimeters (airborne sensors) up to hundreds meters (spaceborne sensors). The images have very high potentials for photogrammetric mapping at different scales and for remote sensing applications. For example, they can be used for the generation of Digital Elevation Models (DEM), that represent an important basis for the creation of Geographic Information Systems, and the production of 3D texture models for visualization and animation purposes.
In the classical photogrammetric chain that starts from the radiometric preprocessing of the raw images and goes to the generation of products like the DEMs, the orientation of the images is a fundamental step and its accuracy is a crucial issue during the evaluation of the entire system. For pushbroom sensors, the triangulation and photogrammetric point determination are rather different compared to the standard approaches for full frame imagery and require special investigations on the sensor geometry and the acquisition mode.
Today various models based on different approaches have been developed, but few of them are rigorous and can be used for a wide class of pushbroom sensors. In general a rigorous sensor model aims to describe the relationship between image and ground coordinates, according to the physical properties of the image acquisition. The functional model is based on the collinearity equations. The sensor model presented in this thesis had to fulfil the requirement of being rigorous and at the same time as flexible as possible and adaptable to a wide class of linear array sensors. In fact pushbroom scanners in use show different geometric characteristics (optical systems, number of CCD lines, scanning mode, stereoscopy) and for each data set specific information are available (ephemeris, GPS/INS observations, calibration, other internal parameters). Therefore the model needs to be dependent on a certain number of parameters that may change for each sensor.
According to the availability of information on the sensor internal and external orientation, the proposed model includes two different orientation approaches.
The first one, the direct georeferencing one, is based on the estimations of the ground coordinates of the points measured in the images through a forward intersection, using the external orientation provided by GPS and INS instruments or interpolated by ephemeris or computed using the orbital parameters (satellite case). This approach does not require any ground control points, except for final checking, and does not estimate any additional parameters for the correction of the interior and exterior orientation. For this reason, the accuracy of this method depends on the accuracy of the external and internal orientation data.
The alternative orientation method, based on indirect georeferencing, is used if the sensor external and internal orientation is not available or not enough accurate for high-precision photograrnmetric mapping. This approach is a self-calibrating bundle adjustment. The sensor position and attitude are modelled with 2nd order piecewise polynomial functions (PPM) depending on time. Constraints on the segment borders assure the continuity of the functions, together with their first and second derivatives. Using pseudo-observations on the PPM parameters, the polynomial degree can be reduced to one (linear functions) or even to zero (constant functions). If GPS and INS are available, they are integrated in the PPM. For the self-calibration, additional parameters (APs) are used to model the lens internal parameters and distortions and the linear arrays displacements in the focal plane.
The parameters modelling the internal and external orientation, together with the ground coordinates of tie and control points, are estimated through a least-squares bundle adjustment using well distributed ground control points. The use of pseudo-observations allows the user to run the adjustment fixing any unknown parameters to certain values. This option is very useful not only for the external orientation modelling, but also for the analysis of the single self-calibration parameter's influence. The weights for the observations and pseudo-observations are determined according to the measurement accuracy. A blunder detection procedure is integrated for the automatic detection of wrong image coordinate measurement. The adjustment results are analyzed in terms of internal and external accuracy. The APs to be estimated are chosen according to their correlations with the other unknown parameters (ground coordinates of tie points and PPM parameters). A software has been developed under Unix environment in C language.
The flexibility of the model has been proved by testing it on MOMS-2P, SPOT-5/HRS, ASTER, MISR and EROS-A1 stereo images. These sensors have different characteristics (single-lens and multi-lens optical systems, various number of linear arrays, synchronous and asynchronous acquisition modes), covering a wide range of possible acquisition geometries.
For each dataset both the direct and indirect models have been used and in all cases the direct georeferencing was not accurate enough for high accurate mapping. The indirect model has been applied with different ground control points distributions (when possible), varying the PPM configurations (number of segments, polynomials degree) and with and without self-calibration. Excluding EROS-A1, all the imagery has been oriented with sub-pixels accuracy in the check points using a minimum of 6 ground control points. In case of EROS-A1, an accuracy in the range of I to 2 pixels has been achieved, due the lack of information on the geometry of the sensor asynchronous acquisition. For the ASTER and SPOT-5/HRS datasets, a DEM has also been generated and compared to some reference DEMs.
New cameras can be easily integrated in the model, because the required sensor information are accessible in literature as well as in the web. If no information on the sensor internal orientation is available, the model supposes that the CCD lines are parallel to each other in the focal plane and perpendicular to the flight direction and estimates any systematic error through the self-calibration. The satellite's position and velocity vectors, usually contained in the ephemeris, are required in order to compute the initial approximations for the PPM parameters. If this information is not available, the Keplerian elements can be used to estimate the nominal trajectory. For pushbroom scanners carried on airplane or helicopter the GPS and INS measurements are indispensable, due to the un-predictability of the trajectory.Note de contenu : 1. INTRODUCTION
1.1. REVIEW OF EXISTING MODELS
1.2. RESEARCH OBJECTIVES
1.3. OUTLINE
2. LINEAR CCD ARRAY SENSORS
2.1. SOLIDSTATE TECHNOLOGY
2.2. ARRAY GEOMETRIES
2.2. 1. Linear arrays
2.2.2. Other geometries
2.3. IMAGING SYSTEM
2.4. SENSOR CALIBRATION
2.4.1. Errors in CCD lines
2.4.2. Lens distortions
2.4.3. Laboratory calibration
2.5. STEREO ACQUISITION
2.5.1. Acrosstrack
2.5.2. Alongtrack
2.6. PLATFORMS
2.6.1. Satellite platforms
2.6.2. Airborne and helicopter platforms
2.7. IMAGE CHARACTERISTICS
2.7.1. Spatial resolution
2.7.2. Radiometric resolution
2.7.3. Spectral resolution
2.7.4. Temporal resolution
2.8. PROCESSING LEVELS
2.9. LIST OF LINEAR ARRAY SENSORS
2.10. CONCLUSIONS
3. DIRECT GEOREFERENCING
3.1. EXTERNAL ORIENTATION FROM GPS/INS
3.1.1. Background
3.1.2. GPS system
3.1.3. INS system
3.1.4. GPS/INS integration
3.1.5. Commercial systems
3.2. EXTERNAL ORIENTATION FROM EPHEMERIS
3.2.1. Orientation with Keplerian elements
3.2.2. Orientation from state vectors
3.2.3. Interpolation between reference lines
3.3. DIRECT GEOREFERENCING
3.3.1. From image to camera coordinates
3.3.2. From camera to ground coordinates
3.3.3. Estimation of approximate ground coordinates
3.3.4. Refinement
3.4. SOME CONSIDERATIONS ON GPS/INS MEASUREMENTS
3.5. ACCURACY EVALUATION
3.6. CONCLUSIONS
4. INDIRECT GEOREFERENCING
4.1. ALGORITHM OVERVIEW
4.2. EXTENTION TO MULTILENS SENSORS
4.3. EXTERNAL ORIENTATION MODELLING
4.3.1. Integration of GPS/INS observations
4.3.2. Function continuity
4.3.3. Reduction of polynomial order
4.4.SELFCALIBRATION
4.5. OBSERVATION EQUATIONS
4.5.1. Image coordinates
4.5.2. External orientation parameters
4.5.3. Selfcalibration parameters
4.5.4. Ground control points
4.6. LEAST SQUARES ADJUSTMENT
4.6.1. Theory of least squares adjustment
4.6.2. Linearization
4.6.3. Design matrix construction
4.6.4. Solution of linear system
4.7. ANALYSIS OF RESULTS
4.7.1. Internal accuracy
4.7.2. RMSE calculations
4.7.3. Correlations
4.7.4. Blunder detection
4.8. FORWARD INTERSECTION
4.9. SUMMARY AND COMMENTS
5. PREPROCESSING
5.1. METADATA FILES FORMATS
5.2. INFORMATION EXTRACTION FROM METADATA FILES
5.3. RADIOMETRIC PREPROCESSING
5.3.1. Standard algorithms
5.3.2. Adhoc filters
6. APPLICATIONS
6.1. WORKFLOW
6.2. MOMS02
6.2.1. Sensor description
6.2.2. Data description
6.2.3. Preprocessing
6.2.4. Image orientation
6.2.5. Summary and conclusions
6.3. SPOT5/HRS
6.3.1. Sensor description
6.3.2. Data description
6.3.3. Preprocessing
6.3.4. Image orientation
6.3.5. DEM generation
6.3.6. Comparison
6.3.7. Summary and conclusions
6.4 ASTER
6.4.1. Sensor description
6.4.2. Data description
6.4.3. Preprocessing
6.4.4. Images orientation
6.4.5. DEM generation
6.4.6. Comparison with reference DEMs
6.4.7. Summary and conclusions
6.5 MISR
6.5.1. Sensor description
6.5.2. Data description
6.5.3. Preprocessing
6.5.4. Image orientation
6.5.5. Summary and conclusions
6.6 EROS-A1
6.6.1. Sensor description
6.6.2. Data description and Preprocessing
6.6.3. Image orientation
6.6.4. Summary and conclusions
7. CONCLUSION AND OUTLOOK
7.1 CONCLUSION
7.2 OUTLOOKNuméro de notice : 13260 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère DOI : 10.3929/ethz-a-004946341 En ligne : http://dx.doi.org/10.3929/ethz-a-004946341 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54943 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 13260-01 35.11 Livre Centre de documentation En réserve M-103 Disponible Verbale Selektion von räumlichen Objekten - ein benutzerorientierter Ansatz für mobile Systeme auf Basis von Ontologien / Joachim Baldegger (2005)
Titre : Verbale Selektion von räumlichen Objekten - ein benutzerorientierter Ansatz für mobile Systeme auf Basis von Ontologien Titre original : [Une sélection verbale des objets géographiques : une conception orientée vers l'utilisateur pour un système mobile sur la base d'une ontologie] Type de document : Thèse/HDR Auteurs : Joachim Baldegger, Auteur Editeur : Zurich : Institut für Geodäsie und Photogrammetrie IGP - ETH Année de publication : 2005 Collection : IGP Mitteilungen, ISSN 0252-9335 num. 84 Importance : 160 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-906467-49-8 Note générale : Bibliographie Langues : Allemand (ger) Descripteur : [Vedettes matières IGN] Bases de données localisées
[Termes IGN] modèle conceptuel de données localisées
[Termes IGN] navigation pédestre
[Termes IGN] objet géographique
[Termes IGN] ontologie
[Termes IGN] représentation mentale spatialeRésumé : (Auteur) The use of speech recognition for the design of user interfaces is an important issue due to the trend in computer sciences towards mobile applications and devices. New technologies like Ubiquitous Computing and Augmented Reality enable totally new applications. This trend is also taking part in Geographic Information Science and Technologies (GIST) since many of human acts - that could be supported by these technologies - have a strong relation to space.
In this thesis, the focus is on the development of speech-based user interface methods. An important functionality is the possibility to select spatial objects or an object space through verbal description (e.g. 'The red house near the church'). This functionality has to be supported for the use with such new applications. But there is no speech recognition software that does support such functionality, yet. With that, in the sense of the 'replacement of keyboard and mouse', today only the keyboard can be replaced totally by speech recognition. The goal of this dissertation is therefore the development of a method that enables the selection of a spatial object in a database through verbal description of the situation.
The separated analysis of the two aspects system and user is an important basis for the elaborated concept. In the case of the system, the focus is laid on the database. Here, questions about form and content of the data and the creation of a usable data basis are studied. As an example, we have chosen pedestrian navigation because it is a basic functionality for mobile information systems. In the case of the user part, the main interest is laid on the user and his verbal selection statement. It is tried to structure the effect of spatial cognition and with that, to make a first step towards a formalization of it.
Based on these considerations, the 3-step model is developed. This model enables the system to extract the target objects in the database. Basic idea is the reduction of the set with the possible target objects in three steps. Each of these steps is based on different criteria.
In the first reduction step, the objects that can be seen by the user are detected by using sensors for positioning and view direction detection. Based on the assumption that the user is only selecting objects he can sec and therefore describe, ail objects out of his visual field drop out as solutions.
The second reduction step contains the problem of the different abstractions of reality by the user and the system. Each user has his own mental model of the visible situation in his mind. This model is influenced by the visualization and the application. The data that is visualized and from which an object should be selected, is stored in a spatial database according to a certain data model. For solving the problem, we have to find a way in which these two models can be mapped onto each other. As soon as this mapping is possible, we can draw a conclusion between the mental model and the data model. Since the selection statement is nothing else than a verbalization of the user's mental model, we can also draw a conclusion between this statement and the objects in the database. With that, a connection between user statement and database has been created.
The third reduction step deals with the analysis of the spatial arrangement. For this, a concept for the verification of the applicability of 22 English relational prepositions is elaborated. We strive for simple algorithms, because the performance of mobile devices is reduced. Based on the idea that the spatial information is also contained on the level of abstraction of the screen objects, several algorithms are developed. These algorithms mainly calculate coordinate comparisons and are therefore quickly processible. During these calculations, the algorithms checks whether a possible target lays within the space of applicability for the respect relational preposition. The defined spaces of applicability indicate a region on the screen for which the detected preposition is applicable.
The elaborated rules and methods are implemented for the 2-dimensional case in prototype software. This prototype is tested with a multi-level test concept. In the operation tests, the focus is laid on indirect selection statements. Beneath this type of tests, we also conduct performance tests and verify several aspects with a questionnaire. The test stage shows that the concept for the verbal selection of spatial objects is successfully applicable and good results in selection efficiency can be achieved.
The developed selection functionality on basis of verbal description of the situation is expanding today's speech-based navigation and commanding possibilities by a spatial component. With that, a further step towards user-friendly mobile services is made.Numéro de notice : 13288 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Thèse étrangère DOI : 10.3929/ethz-a-004906576 En ligne : http://dx.doi.org/10.3929/ethz-a-004906576 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54960 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 13288-01 37.10 Livre Centre de documentation Géomatique Disponible Determination of thermal stratification and turbulence of the atmospheric surface layer over various types of terrain by optical scintillometry / Alexandra Weiss (2002)
Titre : Determination of thermal stratification and turbulence of the atmospheric surface layer over various types of terrain by optical scintillometry Type de document : Thèse/HDR Auteurs : Alexandra Weiss, Auteur Editeur : Zurich : Institut für Geodäsie und Photogrammetrie IGP - ETH Année de publication : 2002 Collection : IGP Mitteilungen, ISSN 0252-9335 num. 075 Importance : 152 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-906467-36-8 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Atmosphère
[Termes IGN] atmosphère terrestre
[Termes IGN] capteur optique
[Termes IGN] rayonnement électromagnétique
[Termes IGN] rayonnement solaire
[Termes IGN] réfraction atmosphérique
[Termes IGN] scintillation
[Termes IGN] turbulenceRésumé : (Auteur) Thermal stratification and turbulence in the atmospheric surface layer cause refraction and scintillation of an optical beam. On the one hand, such atmospherically induced effects are undesirable in many applications which are based on optical wave propagation through the atmospheric boundary layer. Such examples are found in many applications of terrestrial optical surveying. On the other hand, such atmospherically induced effects can be used to derive various meteorological parameters. Based on these consideration the present work deals with the determination of thermal stratification and turbulence of the atmospheric surface layer over different types of terrain by optical scintillometry.
First, in this study a method is introduced and experimentally verified to derive correction values for precise terrestrial geodetic measurements. For highly precise optical direction and distance measurements, such corrections require lineaveraged temperature or refractive index gradients. Secondly, this study investigates how precisely lineaveraged turbulence parameters can be derived in the atmospheric surface layer by scintillometry and whether their derivation deepens our understanding of the structure of the atmospheric surface layer, especially over nonhomogeneous terrain. Here, the main focus lies in the investigation of the accuracy of the turbulent sensible heat and momentum fluxes, and the dissipation rate of turbulent kinetic energy, which are of grave importance for many meteorological applications. This work is based on various field experiments conducted with a socalled displacedbeam scintillometer under different atmospheric conditions. The experimental sites varied from homogeneous and flat terrain to flat, nonhomogeneous terrain up to slanted, nonhomogeneous terrain in an alpine valley. For validation of the method, additional meteorological measurement techniques are used and are considered in the data analysis, such as eddycorrelation measurements with sonic anemometerthermometers and Krypton hygrometers, and temperature profile measurements with Pt 1000 sensors.
The derivation of the thermal stratification from the scintillation method is especially dependent on the accuracy of the derived turbulent sensible heat flux. In the scope of this study, satisfactory accuracy of the derived turbulent sensible heat fluxes is obtained, even for nonhomogeneous terrain. It is shown that the presented method is applicable for deriving, lineaveraged refraction correction values over various types of terrain and for different atmospheric conditions with a good temporal resolution. This result is confirmed by comparisons with local temperature profile measurements. The linfitations of this method are discussed on the basis of the experimental datasets. For instance, under neutral conditions, with weak thermal turbulence, the derivation of accurate values of the turbulent momentum flux can be problematic with this method. However, in this work it is shown that the scintillation method gives accurate values under many atmospheric conditions including the turbulent momentum flux and for several other turbulence parameters. On the basis of the field experiments, new insights into the turbulence structure of the surface layer can be achieved by scintillometry, even over nonhomogeneous terrain. In this context the turbulent structure in an alpine valley is analysed and described under various boundary layer features.Numéro de notice : 15052 Affiliation des auteurs : non IGN Nature : Thèse étrangère En ligne : http://dx.doi.org/10.3929/ethz-a-004283039 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=55054 Réservation
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