Map projections: cartographic information systems

In the context of Geographical Information Systems (GIS) the book offers a timely review of map projections (sphere, ellipsoid, rotational surfaces) and geodetic datum transformations. For the needs of photogrammetry, computer vision, and remote sensing space projective mappings are reviewed

Solving algebraic computational problems in geodesy and geoinformatics: the answer to modern challenges

While preparing and teaching 'Introduction to Geodesy I and II' to - dergraduate students at Stuttgart University, we noticed a gap which motivated the writing of the present book: Almost every topic that we taughtrequiredsomeskillsinalgebra,andinparticular,computeral- bra! From positioning to transformation problems inherent in geodesy and geoinformatics, knowledge of algebra and application of computer algebra software were required. In preparing this book therefore, we haveattemptedtoputtogetherbasicconceptsofabstractalgebra which underpin the techniques for solving algebraic problems. Algebraic c- putational algorithms useful for solving problems which require exact solutions to nonlinear systems of equations are presented and tested on various problems. Though the present book focuses mainly on the two ?elds,theconceptsand techniquespresented hereinarenonetheless- plicable to other ?elds where algebraic computational problems might be encountered. In Engineering for example, network densi?cation and robotics apply resection and intersection techniques which require - gebraic solutions. Solution of nonlinear systems of equations is an indispensable task in almost all geosciences such as geodesy, geoinformatics, geophysics (just to mention but a few) as well as robotics. These equations which require exact solutions underpin the operations of ranging, resection, intersection and other techniques that are normally used. Examples of problems that require exact solutions include; three-dimensional resection problem for determining positions and orientation of sensors, e. g. , camera, theodolites, robots, scanners etc. , VIII Preface coordinate transformation to match shapes and sizes of points in di?erent systems, mapping from topography to reference ellipsoid and, analytical determination of refraction angles in GPS meteorology

Map projections: cartographic information systems

This book offers a timely review of map projections including sphere, ellipsoid, rotational surfaces, and geodetic datum transformations. Coverage includes computer vision, and remote sensing space projective mappings in photogrammetry

NN - Aus der Werkstatt eines Geodäten

Das Normal-Null (NN), bei Höhenangaben am Wegesrand als „Höhe über NN" mehr oder weniger bekannt, eröffnet zahlreiche Fragen: Was ist ein Normal-Null? Was bedeutet eine Höhenangabe über Normal-Null? Die Beantwortung dieser Fragen hat den Berufsstand der Geodäten mit dem Fachgebiet Geodäsie mitgeprägt. (yeco8mcmx: Teilung der Erde, historische Bezüge in Aristoteles: Metaphysik, Buch 2, 997 b, 26, 31). Die geodätische Höhenbezugsfläche als Normal-Null entstammt einem Vorschlag von C. F. Gauß (1828), im Detail ausgearbeitet von seinem Schüler J. B. Usting (1873, Göttinger Schule): Der mittlere Meeresspiegel ist das Normal-Null, genannt Geoid, physikalisch eine Äquipotentialfläche des Schwerepotentials zu einem Referenzzeitpunkt. Denken wir uns den mittleren Meeresspiegel, beispielsweise über einen Kanal, fortgesetzt „unter die feste Erde", so erhalten wir die Fläche des Normal-Null, auf welche sich lokale Höhenangaben beziehen. Neben der Höhenbezugsfläche Geoid ist auch die Höhenangabe eines Punktes auf der Erdoberfläche physikalisch, nämlich im Sinne dynamischer Höhen als gravitative Spannung gegen Erde, als Unterschied des Schwerepotentials W - W0 gegenüber dem geoidalen Potentialwert W0 definiert. Konkret sind metrische Höhenangaben im Sinne des obigen Beispiels „orthometrisch", das heißt sie geben die „Länge der Lotlinie" von einem Punkt der Erdoberfläche zu einem Projektionspunkt „unterhalb" auf dem Geoid an. Genauer gesagt bestimmt die Länge der geodätischen Linie zwischen Oberflächenpunkt und Geoid die geodätische Höhe eines Punktes, namentlich gerechnet mit einer konform-flachen Metrik und dem halbierten Quadrat des Schwerevektors als Konformfaktor. Der Gradient in einem derartig physikalisch definierten Höhensystem gibt an, „wohin das Wasser fließt". So ist eine topographische Situation vorstellbar, in der Wasser einen geometrischen Berg „hinauffließt"

The Falling Lake Victoria Water Level: GRACE, TRIMM and CHAMP Satellite Analysis of the Lake Basin

In the last 5 years, Lake Victoria water level has seen a dramatic fall that has caused alarm to water resource managers. Since the lake basin contributes about 20% of the lakes water in form of discharge, with 80% coming from direct rainfall, this study undertook a satellite analysis of the entire lake basin in an attempt to establish the cause of the decline. Gravity Recovery And Climate Experiment (GRACE), Tropical Rainfall Measuring Mission (TRMM) and CHAllenging Minisatellite Payload (CHAMP) satellites were employed in the analysis. Using 45 months of data spanning a period of 4 years (2002-2006), GRACE satellite data are used to analyse the variation of the geoid (equipotential surface approximating the mean sea level) triggered by variation in the stored waters within the lake basin. TRMM Level 3 monthly data for the same period of time are used to compute mean rainfall for a spatial coverage of .25.25 (2525 km) and the rainfall trend over the same period analyzed. To assess the effect of evaporation, 59 CHAMP satellite's occultation for the period 2001 to 2006 are analyzed for tropopause warming. GRACE results indicate an annual fall in the geoid by 1.574 mm/year during the study period 2002-2006. This fall clearly demonstrates the basin losing water over these period. TRMM results on the other hand indicate the rainfall over the basin (and directly over the lake) to have been stable during this period. The CHAMP satellite results indicate the tropopause temperature to have fallen in 2002 by about 3.9 K and increased by 2.2 K in 2003 and remained above the 189.5 K value of 2002. The tropopause heights have shown a steady increase from a height of 16.72 m in 2001 and has remained above this value reaching a maximum of 17.59 km in 2005, an increase in height by 0.87 m. Though the basin discharge contributes only 20%, its decline has contributed to the fall in the lake waters. Since rainfall over the period remained stable, and temperatures did not increase drastically to cause massive evaporation, the remaining major contributor is the discharge from the expanded Owen Falls dam