Editorial: Sumptibus & typis aeneis Henrici Hondij
Departamento: Biblioteca de la Universidad Complutense de Madrid - Biblioteca Histórica Marqués de Valdecilla
CDU: 912
Notas: Las ilustraciones son grabados calcográficos de mapas a color y a doble página.
Iniciales xilográficas con motivos vegetales.
Grabado calcográfico a color a doble página (v. de B3 y r. de B4) representado a G. Mercator y J. Hondius
Resumen: A conformal approximation to the Transverse Mercator (TM) map projection, global in longitude lambda and isometric latitude q, is constructed. New formulas for the point scale factor and grid convergence are also shown. Assuming that the true values of the TM coordinates are given by conveniently truncated Gauss-Kruger series expansions, we use the maximum norm of the absolute error to
measure globally the accuracy of the approximation. For a Universal Transverse Mercator (UTM) zone the accuracy equals 0.21 mm, whereas for the region of the ellipsoid bounded by the meridians +/- 20A degrees the accuracy is equal to 0.3 mm. Our approach is based on a four-term perturbation series approximation to the radius r(q) of the parallel q, with a maximum absolute deviation of 0.43 mm. The small parameter of the power series expansion is the square of the eccentricity of the ellipsoid. This closed approximation to r(q) is obtained by solving a regularly perturbed Cauchy problem with the Poincar, method of the small parameter.
Departamento: Biblioteca de la Universidad Complutense de Madrid - Biblioteca Histórica Marqués de Valdecilla
CDU: 912
Notas: Ilustraciones calcográficas, principalmente mapas, planos dobles con texto impreso en el recto, algunos fechados en el último tercio del S. XVI y otros firmados, entre otros por Mercator y el propio Ortelio y además un retrato del autor en B4 v.: "Papius" y un plano, de Ortelio, del monasterio de El Escorial
Resumen: In the comparison of light pollution between two countries, there are some difficulties because of geographical, cultural and economical differences. The trouble is even worse considering all different systems of outdoor lighting.
As first step, to contrast light pollution between countries, a group of close nations have been chosen with different population densities, size, built surface, etc.
As a parameter to compare the emission of each country,
the NOAA’s images (DMSP Satellite, OLS “VIS” band 0.40-1.10 um) flux were used and NASA’s software World Wind were employed to solve distortion problem of the Mercator projection.
This software allow to draw frontiers over countries, so it is possible to make a particular study of them. In these images all illuminated regions are saturated, so the number of counts don’t represent the flux emitted from that region, although that number is proportional to region’s area.
As it is known the area of each country it is possible to calculate the density of illuminated area per person and proportion of illuminated territory. These parameters allow to compare the aspect of the country from space.
This parameter is very influenced by population’s density, so it is interesting to compare it with other parameters as urban surface, population density, street lamp density. etc.
In this study we show some conclusions of the possible roots of the differences found between countries’ illumination.
