The course "Elements of remote sensing applied in geography", developed by lecturer Dr. Florin Achim, is intended for students from the specializations "Territorial Planning" and "Meteorology - Hydrology" within the Faculty of Geography of the University of Bucharest. It responds to an essential requirement of higher education: the acquisition and use by future professionals of the most advanced techniques and methods for investigating the geographical environment. Remote sensing is one of them, making it possible to observe with great accuracy the earth's surface, the acquisition and exploitation of a huge volume of information (images and measurements) about the Earth, about the elements and phenomena in our living environment.
We understand why the author was concerned that, from the first pages of the course, to clarify the content of the terms "remote sensing" and "geographical remote sensing".
Regarding the term "remote sensing", it would first resort to the strictly etymological meaning, that of remote sensing, and then to reach the acceptance of the technique of observing the Earth and the Universe. Moreover, remote sensing is considered a technology in which certain stages and operations follow one another. Indeed, remote sensing - we refer to space remote sensing - involves a flow of technical operations: remote capture (airspace, outer space) of electromagnetic waves emitted or remitted from the earth's surface using sensors installed on board aerial platforms (aircraft, helicopters, drones) or on space platforms (especially satellites, but also space stations and probes); transmission of information (also electromagnetic waves) to earth stations; transformation of electromagnetic waves into digital images and maps, into quantitative indices and their storage; processing images / geospatial data and making derived documents (images in natural and false colors, images in certain spectral bands and composite images; satellite / spatial maps; Numerical Terrain Models / DEMs; sets of qualitative and quantitative indices regarding the constituents of the terrestrial environment: air, inland and ocean waters, vegetation and soils, rock and relief, settlements, agricultural crops, land transport routes, etc.); dissemination of results, respectively delivery of specific products to different users in the field of scientific research and in the field of practical applications.
The phrase "geographical remote sensing", which we retain from the course content, is explained by lecturer Dr. Florin Achim by the diversity of applications that aerial photographs and satellite images have in current geographical research.
In the course structure we find, in the first part, the chapters regarding the physical and technical bases of remote sensing: the principles of electromagnetic remote sensing, the structure of the electromagnetic spectrum, the behavior of electromagnetic waves emitted or remitted by the earth's surface (reflection, refraction, diffraction, absorption, diffusion). . Then, the content is carried out on the two branches of remote sensing: aerial photogrammetry and spatial (satellite) remote sensing. The largest share is held by the chapters on satellite remote sensing. We note here that in Western professional environments, the term remote sensing applies only to satellite remote sensing (remote sensing). Also, the remote sensing of the Earth from space is designated by the expressions "Earth Observation", respectively "Earth Observation", "L'Observation de la Terre".
These chapters cover a number of specific topics: remote sensing systems (passive remote sensing and active remote sensing), remote sensing sensors (television cameras, radiometers, radars, lidars) and satellite imaging (image processing; obtaining derived remote sensing products; geospatial data interpretation). by visual and computerized analysis; delivery of final materials to different users).
Necessarily, an important part of the course is dedicated to remote sensing applications in geographical sciences (general geography, regional geography, branch / private geographic sciences) and in many economic and engineering fields, thanks to the enormous volume of high quality data on the earth's surface. , to our living environment. With the 24 subjects, the field of applications extended the conventional sphere of the object of geography, appealing to a series of new directions, which developed the thematic area of the deepenings through examples and demonstrations. Applications in meteorology and climatology, in hydrology and oceanography, in biogeography and ecology, but also in agriculture and forestry, in territorial planning, etc. are brought to attention.
We have the certainty that the material made, in printed and electronic form, by lecturer Dr. Florin Achim, will successfully fulfill its role of informational support for geography students, stimulated by the advantages of remote sensing and aerial photogrammetry in terrestrial research, both through observations over time. real, especially by exploiting geospatial databases.
Assoc. Dr. Vasile Loghin