Contour Map Analysis Research Articles

Analysis of Contour Map of Natural Radiation in Japan

Analysis of Contour Map of Natural Radiation in Japan

Analysis of contour map of natural radiation in Japan.

Natural background radiation in Japan was analyzed based on surveyed data which were rearranged from macroscopic points of view. The background levels were classified into seventeen groups from which a contour map was made by simple interpolations. The general pattern obtained showed that high levels are prominent in Hida Mountains-Wakasa Bay area and Joetsu-northern Kanto provinces, and low levels are prominent in Hokkaido and northern Tohoku districts along with Kanto Plain. The whole area was further divided into two classes according to whether the level is higher than the country-wide mean level. A boundary between the two classes seen in Chubu District was found almost exactly coincides with Itoigawa-Shizuoka Tectonic Line. Kanto Mountainland was found to have higher levels than its neighborhood, which supports the current idea that old geology of granitic rocks gives high level radiation. A good correspondence could be seen between the radiation contours and every tectonic line proposed as the eastern border of Fossa Magna which is important in the tectonics of Japan Islands. It was then anticipated that informations of the natural radiation will give valuable side evidences to infer the geologic history of Japan Islands.

TIME LAG RESPONSE IN BOULDER CLAY WELLS

Well hydrograph and change in well level map analysis, associated with a small boulder clay catchment, detected a time lag response with the causal factors rainfall and potential evapotranspiration. The main purpose of this investigation was to test whether a suitable statistical method can detect this time lag and therefore translate this mechanism into quantitative terms. The analysis proved to be very successful despite some defects in the original data. The results confirm the general trends indicated in the earlier hydrograph and contour map analyses.

Analysis of contour maps by optical diffraction

The orientation and spatial frequency of contours can be analyzed by optical diffraction. A reduced, transparent replica of the contour map functions as a diffraction grating through which coherent light is transmitted. With suitable optics, a diffraction pattern is produced that is the two-dimensional Fourier amplitude transform of the input map. The transform shows the distribution of orientations and spatial frequencies of the input elements. Because contours occur frequently as groups of nested curves of similar shape they usually generate intense diffraction patterns. With additional optics, a spatially filtered reconstructed image can be produced, enhancing the study of relatively obscure features and aiding in the analysis of a combination of distributions. Results are presented for both hypothetical and real contour maps, in terms of both transforms and spatially filtered imagery.