Ebook: Digital Photogrammetry: A Practical Course

1.1 Basic idea and main task of photogrammetry If you want to measure the size of an object, let’s say the length, width and height of a house, then normally you will carry this out directly at the object. Now imagine that the house didn’t exist anymore – it was destroyed, but some historic photos exist. Then, if you can determine the scale of the photos, it must be pos- ble to get the desired data. Of course you can use photos to get information about objects. This kind of - formation is different: So, for example, you may receive qualitative data (the house seems to be old, the walls are coloured light yellow) from photo interpre- tion, or quantitative data like mentioned before (the house has a base size of 8 by 6 meters) from photo measurement, or information in addition to your background knowledge (the house has elements of the “art nouveau” style, so may be c- th structed at the beginning of the 20 century), and so on.

The third edition is an ''all-in-one'' combination of basic theory and practical exercises with software and data included on a CD-ROM. Potential readers/users are students of Photogrammetry, Geodesy, Geography and other sciences, but also all who are interested in this topic. No prior knowledge is necessary, except the handling of standard PCs. Theory is presented true to the motto ''as little as possible, but as much as necessary''.

The main part of the book contains several tutorials. In increasing complexity, accompanied by texts explaining further theory, the reader can proceed step by step through the particular working parts. All intermediate as well as the final results are discussed with reference to accuracy and error handling, and included on the CD-ROM to provide controls. Most of the standard work in Digital Photogrammetry is shown and trained for example scanning, image orientation, mono and stereo plotting, aerial triangulation measurement (manual and automatic), block adjustment, automatic creation of surface models via image matching, creation of ortho images and mosaics, and others. Not only standard situations are dealt with but also more complex ones, such as unknown camera data, extreme relief or areas with very low contrast. Examples of both aerial and close-range photogrammetry present the power of these type of measurement techniques.

The software is not limited to the example data included but may be used for personal projects. Part of the book comprises a complete description of the software. On the CD-ROM, versions in German, English and Spanish are available. Even 3-D images can be viewed with the accompanying 3-D glasses.