Overview of Available Open-Source Photogrammetric Software, its Use and Analysis

The current technological era provides a wide range of geodetic procedures and methods to document the actual state of objects on the Earth surface and at the same time course and shape of surface itself. Digital photogrammetry is one of these technologies, it allows the use of methods such as single-image photogrammetry, stereo photogrammetry (optical scanning), convergent imaging and SfM method (structure-from-motion) with final data in the form of point clouds, digital spatial models, orthophotos and other derived documents. Similar outputs can be obtained also by other technologies, mainly by terrestrial laser scanning, whilst each of the two technologies offers certain advantages and disadvantages. Especially purchasing and operating costs are one of the major drawbacks of laser scanning (while being an advantage of photogrammetry). In recent years, there has been a significant increase in development and creation of new, freely accessible (open-source) photogrammetric software, thus reducing these financial demands even more. The aim of this paper is to provide a basic overview of some of the most suitable open-source photogrammetric software and point out their strengths and weaknesses.