Variation of soil surface image brightness in the function of the solar zenith angle and the atmosphere state, described by its optical thickness for chosen wavelength of 850 nm, is examined in this paper. The issue is discussed on examples of four surfaces: two uncultivated desert, the relatively smooth silty and the very rough rocky, as well as the two cultivated, with randomly dispersed soil aggregates and their directional distribution with the furrow microrelief. Data generated by the model predicting the hemispherical-directional reflectance from the surfaces mentioned above were used in this paper. The data for the surfaces in the given illumination conditions are presented in the form of this reflectance distributions for all the possible directions, normalised to the nadir. Discussion about practical applications of the non-Lambertian behaviour of soil surfaces to obtain more detailed and reliable information of the surface properties using remote sensing finalizes the paper.
METHODS AND APPROACHES APPLIED TO MULTISENSORAL DATA FUSION
Autor
Marek Mróz, Małgorzata Szumiło
Pages
17–28
Keywords
remote sensing data fusion
Abstract
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The paper presents the ideas, methods and tools used in fusion of remotely sensed data acquired by different systems and sensors. It is a contribution to the discussion on methods and approaches applied to fusion of imagery data having different spectral and spatial resolution, and on the necessity of elaboration of any formal framework of data fusion process quality assessment. This paper is general, not pretending to be an exhaustive revue of methods and techniques of data fusion. The authors show certain solutions in the context of commercial software functionality but they avoid any formal evaluating of them.
Typical approach to classification of objects on remote sensing images, which assume detection of terrain details being grouped into several thematic categories, represented by radiometric properties of the multispectral raster image, still needs more and more sophisticated methods of increasing efficiency. Among currently used solutions, on special attention claimed methods stated as the object-oriented, which are based on analyses of parts of the bitmap, grouped according to criteria of homogeneity. It is possible to carry out the image segmentation using various methods, which are developed within couple of informatics’ sciences. In interpretation of remote sensing images there were elaborated approaches adapted to specific of those types of images. Such special use of grouping technique of objects fulfilled the particular accuracy criteria were investigated here. There were described the density-based clustering method of large databases and their implementation adapted to raster image analyses, and then, the possible solution using accessible vector information was suggested. The text is illustrated using the simplified model of remote sensing image.
Atmosphere between an object and a satellite detector is the most important element, which decided about the radiation registered by satellite sensor. However, atmospheric correction is mostly neglected during satellite image processing. It’s implicated by fact that to estimate the influence of atmospheric conditions, a lot of different meteorological parameters and model of atmosphere are needed. In case of archived images gathering this kind of data is often difficult or even impossible. Therefore standard atmosphere models which described average atmospheric conditions on different areas are used. In some application atmospheric correction is not needed (i.e. qualitative analyses, visual interpretation) but for quantitative analyses or multitemporal analyses this correction is very important to obtain correct results. This article presents results of researches on influence of atmospheric correction on the process of multispectral classification. It was found that classification of atmospheric corrected images make better classes delimitation possible.
The multispectral classification is the most common algorithm, which is applied for the creation of thematic maps (like land use / land cover maps) based on the satellite images. To obtain the final classification result having quality of cartometric material, it is requisite to carry out the geometric correction process. It’s possible to realize this process in two way: first of them consists in geometric image correction and to continue by classification of image being already georeferenced yet. Second way is to classify the source image and to continue by geometric correction of the image already classified. However, knowing the image digital treatment nature, we should ask – are the both results the same or not? The presented study show the results of the researches about impact of the moment of the image geometric correction versus of multispectral classification process. This study was done at the base of SPOT5 satellite images for two test sites in Poland: Żuławy (consolidate agrarian structure) and Wyszków (fine agrarian structure). According to the results the influence of the geometric correction of satellite images on the results of multispectral classification is exist. Nevertheless, the most important element of image processing is the algorithm, which is chosen for the image resampling and the pixel size of the resampled image.
USE OF THE ORTHOPHOTOMAP IN THE PROTECTION PLAN FOR KARKONOSKI NATIONAL PARK
Autor
Grzegorz Rączka, Paweł Strzeliński
Pages
67–75
Keywords
orthophotomap, protection plan, Karkonoski National Park
Abstract
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The paper presents the scope of orthophotomap usage during forest management works within drawing up of the conservation plan of the Karkonoski National Park. The works have been conducted in years 2000-2002, mainly by Bureau of Forest Management in Brzeg. Orthophotomap (resolution of terrain pixel – 36 cm) has been created on the basis of (B/W, natural colour lub IRC) aerial photographs acquired (taken) in 2001. The map has covered the area of Karkonoski National Park and its protection zone. The orthophotomap has been used mainly for three groups of tasks. The first group of tasks has been concerned with correction and determination of borderlines: correction of coordinates of geodetic division (except for points stabilized by geodetic stones); correction of forest subcompartment borderlines; correction of borderlines of areas between forest and non-forest grounds (mainly ski trails and ski lifts). Correction of potential range of plant communities has been carried out, and plant communities above upper borderline of forests have been mapped. Routes of lineal items (roads, paths, streams) have been also verified. The second group of tasks has been related to orthophotomap use for forest inventory; mainly for inventory of the areas covered by dead standing and dead lying wood; inventory of intermixtures of tree species in upper layers of stand; appointing of intermixture forms; defoliation and degree of tree-crowns damages. Within the third group of tasks, the position of regular sample areas on the orthophotomap (necessary for planned measurements and estimations) has been fixed. Orthophotomap is very useful for forest management works because the possibilities that it gives exceed costs borne for its preparation. Use of orthophotomap allows to shorten the terrain works, to abandon some of measurements (especially geodetic ones) and to apply remote-sensing and photogrametric analyses.
The article presents some variants and methods of angular surveys conducted on engineering objects by using measuring adapters for theodolites and total-stations. The application of the described authors’ ideas makes it possible an angular connection to control points located near an instrument. Such approach enables a surveyor to rationalize measuring procedures.
APPLICATION OF ROBUST ESTIMATION METHODS TO GEODETIC SURVEYS OF BUILDINGS’ VERTICAL DISPLACEMENTS
Autor
Krzysztof Mąkolski, Zbigniew Muszyński, Edward Osada
Pages
85–97
Keywords
geodetic surveys of vertical displacements, robust estimation methods, buildings’ settlement
Abstract
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The paper refers geodetic surveys of vertical displacements. The possibilities of wider use robust estimation methods were studied. Till now these methods were used only to identification of constant reference points. In the paper there are following methods: Huber's, Hampel's and linear (provided in geodetic software: „Niwelacja” [Osada 2000]) which were used to periodical surveys' final adjustment. Then the values and significances of displacements were calculated and they were compared with the results from classical method. The calculations were done for eight check surveys of residential buildings localized in Traugutta Street in Wrocław, which were flooded in 1997.