Map grids and datums

Gábor Timár

Gábor Molnár

György Busics

ISBN 978-963-284-389-6 (PDF)

ISBN 978-963-284-390-2 (HTML)

This book is freely available for research and educational purposes. Reproduction in any form is prohibited without written permission of the owner.

Made in the project entitled "E-learning scientific content development in ELTE TTK" with number TÁMOP-4.1.2.A/1-11/1-2011-0073. Consortium leader: Eötvös Loránd University, Consortium Members: ELTE Faculties of Science Student Foundation, ITStudy Hungary Ltd.

Table of Contents

1. Introduction
2. Planar and spatial coordinate systems
2.1 Units used in geodetic coordinate systems
2.2 Prime meridians
2.3 Coordinate systems and coordinate frames
3. Shape of the Earth and its practical simplification
3.1 Change of the assumed shape of the Earth in the science
3.2 The geoid and the ellipsoid of revolution
3.3 Types of the triangulation networks, their set up and adjustment
4. Geodetic datums
4.1 Parameters of the triangulation networks
4.2 The ’abridging Molodensky’ datum parametrization method
4.3 The Burša-Wolf type datum parameters
4.4 Comparison of the abridging Molodensky and Burša-Wolf parametrization
4.5 Estimation of the transformation parameters
4.6 The correction grid (GSB)
5. Maps and projections
5.1 Map projections and their parameters
5.2 Transformation between projected coordinates
5.3 Substituting projections
5.4 Sheet labeling system of maps, the geo-reference provided by the labels
6. Geo-reference of the maps
6.1 The geo-reference and the rectification
6.2 The projection analysis and the deliberate selection of projection
7. Vertical geo-reference
7.1 Ambiguities in height definition
7.2 Height definitions, elevation measurements
7.3 Ambiguity of the sea level: vertical datums
8. Terrain and elevation models
8.1 Definition and types of the terrain models
8.2 Making and characteristics of the raster-based terrain model
8.3 Availability of the terrain models
8.4 The effect of the built environment and the vegetation: elevation models
9. Ortho-rectification of aerial photos
9.1 The goal of the ortho-rectification
9.2 The camera model and the internal orientation
9.3 The external orientation
9.4 Camera model of compact digital photo-cameras
9.5 The ortho-rectification process
9.6 The effect of the applied elevation model
9.7 Making of digital anaglif images
9.8 Rectification of the photographed documents and maps
10. References – Recommended literature
A. Appendix: procedures to estimate the datum transformation parameters
Estimation of the abridging Molodensky-parameters, providing the best horizontal fit
Estimation of the Burša-Wolf parameters