It has been recently observed that aircrafts tend to be replaced by light, simple structure unmanned aerial vehicles (UAV) or mini unmanned aerial vehicles (MUAV) with the purpose of updating the field of aerial photogrammetry. The built-in digital photo camera takes images of the Earth’s surface. To satisfy the photogrammetric requirements of the photographic images, it is necessary to carry out the terrestrial project planning of the flight path before the flight, to select the appropriate flying height, the time for acquiring images, the speed of the UAV, and other parameters. The paper presents the results of project calculations concerning the UAV flights and the analysis of the terrestrial images acquired during the field-testing flights. The experience carried out so far in the Lithuanian landscape is shown. The taken images have been processed by PhotoMod photogrammetric system. The paper presents the results of calculation of the project values of the UAV flights taking the images by digital camera Canon S100 and the analysis of the possibilities of the UAV orthophoto images’ mode.

The determination of parameters of the Earth's ellipsoid is quite a difficult task that gives no rest to scientists to this day. One of the more famous works is the Struve Geodetic Arc, which was stretched from the Black Sea to the Arctic Ocean by employing the method of a triangulation network and which is included in the UNESCO World Heritage Site list. However, until this project was implemented, many steps of scientific and technological advancement had to be taken, the entirety of which created the conditions for the realization of this project. A study of the method of triangulation measurements, the development of geodetic devices, the state politics of the Russian Empire in the 17th–19th centuries in the field of geodesy, and the development of triangulation during this period are presented in the article. Moreover, a study of the origins of the Struve Geodetic Arc project that led to such a grand result is conducted. The obtained results reveal that certain factors predetermined the favourable conditions for the successful execution of the project of this geodetic arc.

In Lithuania, the old archival topographic maps of locations of small and medium scale and 1 : 10,000 scale contour photo plans were created on the basis of aerial images. The material of these scales provides documented records on the condition of the objects in the location and the landscape at the moment of aerial photography. Those maps can be used to restore the accurate topographic image of the terrain and buildings in 1945–1951 and in later years and perform the necessary topographic, photogrammetric, and geodetic measurements of the parameters of objects, to identify the location of objects and changes. This information is necessary for a variety of disputed property issues and for building farmhouses in reserves, in areas of forestry land parcels, and for assessment of changes in the landscape. Studies of landscape changes are needed for the assessment of renaturalization processes. This paper presents the geodetic method used for geomorphological changes at the channel of River Žalesa during the period 1942–2017, based on the collected archival cartographic materials: historical topographic maps from archive of the Lithuanian State Company Land Fund, Land Information System, and land management projects and orthophoto maps from Lithuanian spatial information portal and free open‐access Sentinel‐1 satellite data from the Copernicus Open Access Hub.

Effective forest management systems based on comprehensive tools need to be developed for the analysis and assessment of forest cover change. This requires a wide range of data, starting from old maps, which allow the reconstruction of spatially referenced information on past forest areas, to recently collected data. The research methodology proposed in this paper involves a combined analysis of data from different sources, using statistical, comparative, and visual analysis methods. The case study is Jurbarkas District of the Republic of Lithuania characterized by a high land productivity score. The research found that the highest forest cover areas were in the 19th century and the lowest in the 20th century. It can be seen that during the period under research, forest areas ‘migrated’ from an area favorable for agricultural activities to a less favorable area with higher slopes. Permanent forest cover areas and the age of the dominant trees have been identified. The age of the trees in the forest areas has allowed for the identification of the periods when the most intensive logging took place. The rate of forest cover change made it possible to predict the total disappearance of the forest areas provided that the factors influencing forest cover change at that time remained unchanged. If the trends in forest change in Jurbarkas District had been maintained in the period between the 19th and 20th centuries, the forest would have disappeared in 2006.

Under the conditions of a global reduction in forest areas and climate change, it is important to preserve as many tree-covered areas as possible and understand change trends. The article purpose – aims at identifying forest area change trends of 19th-20th c. in the current forest land of the eldership Raudonė. In the research, historical topographic maps compiled during different periods, and 2019 data from the forest registry are used. The research method of a comparative analysis is employed. The change in forest areas was analysed, and forest areas that remained unchanged for 200 years were identified. The comparison of current forest areas reflected in the cadastral data and forest areas of the considered period allowed identifying the tendency of assigning land the purpose of forest land. During the research, the period with largest forest areas was determined to be the 19th c., and with the smallest – 1st half of the 20th c. During the Soviet period, forests areas were increasing, but did not achieve the same level as in the 19th c.