MERCURY - A NEW MAP WITHIN THE SERIES OF MULTILINGUAL RELIEF MAPS OF THE TERRESTRIAL PLANETS AND THEIR MOONS Shingareva, K.B.1, Krasnopevtseva, B.V.1, Leonenko, S.M.1, Buchroithner, M.F.2 and Waelder, O.2 1Moscow State University for Geodesy and Cartography. 4 Gorokhovsky per, Moscow 103064, Russia. E-mail: [email protected] 2Dresden University of Technology. Momsenstr.13, Dresden 01187, Germany. E-mail: [email protected] ABSTRACT Under the guidance of the ICA Commission on Planetary Cartography a preliminary version of a Mercury Map was published. It belongs to a series of multilingual relief maps of terrestrial planets and their moons. The idea to compile such a series was first discussed in Barcelona during the ICA Congress in 1995. Subsequently the preliminary version of the Mars Map was exhibited at the ICC 1995 in Stockholm. Based on the input from this congress some corrections and improvements were made. As the first official map of the series it was presented at the ICA Congress in Ottawa, Canada, in August 1999. Its scale amounts to 1:25 000 000. As the next map sheets of this series, the Venus and Moon Maps were planned later compiled and printed. Besides the shaded relief representation a request was that each map has to include information about various astrophysical, geodetic etc. parameters of the respective celestial body, a list of Latin terms for relief feature designation and a list of relevant space missions to this planet or the planet's moon. Due to format restrictions this information has to be printed on the back side of the map, and that in 5 languages, namely German, Russian, English, French and Spanish. Hence, the production of these maps can be considered as the first attempt to create multilingual planetary maps. The “Atlas of Terrestrial Planets and their Moons” published by the Moscow State University for Geodesy and Cartography in 1992 was chosen as a base for the map series. The next map prepared within this series is the Mercury Map. Two Mercury maps from the above mentioned atlas were used: the Mercury Albedo Map and the Mercury Shaded Relief Map, both at a scale of 1:35 000 000. Considering the fact that that relief information exists only for about 40% of the planet’s surface, the new Mercury Map was compiled as a combination of these two maps. The surface is presented in two hemispheres at a final scale of 1:17 800 000. The paper format of the sheet is the same as those of the previous planetary maps of this series. 1. INTRODUCTION In the new millennium space activities will increase significantly. Evidence for this is given by the manned flight of the International Space Station (ISS) and regular launches of automatic probes and stations to Mars, asteroids etc. Within the last few years it became quite obvious that in the future more and more planetary lander and surrounder missions will be carried out. On the other hand, the average citizen’s knowledge about the atmospheres, shapes and reliefs of the planets is still rather meager. In order to supply the interested public as well as experts with information about the "extraterrestrial geography", in particular the relief of planets, a new series of relief maps has been launched with the publication of the Mars, Venus, and Moon Maps during last five years, the map of Mercury representing the continuation of this series now. The demonstration of the Mars Map at the 1999 ICA Congress in Ottawa [1], the Venus Map at 2001 ICA Conference in Beijing [2], and the Moon Map at the 2002 Interkarto 8 Conference in St.Petersburg [3] made it clear that the eager international interest in such a map series certainly justifies its production efforts. Moreover, the maps of this series are also used as a base for the new series of multilingual planetary maps prepared at Eotvos University in Budapest. The maps of this new series are compiled on the other languages, namely for the use in Hungary, Poland, the Czech Republic, Bulgaria and Croatia. The authors of this paper decided to proceed in the same way as for the compilation of the other maps in this series, namely to display preliminary version of the Mercury Map at a scale 1: 17 800 000 during the 2003 Durban ICA Congress. After some discussion of the map contents (and hopefully supply of additional information!), they envisage to produce a map of increased quality. Proceedings of the 21st International Cartographic Conference (ICC) Durban, South Africa, 10 – 16 August 2003 ‘Cartographic Renaissance’ Hosted by The International Cartographic Association (ICA) ISBN: 0-958-46093-0 Produced by: Document Transformation Technologies The “preprint” has a format of 55 cm x 84 cm, the two hemispheres covering a printing area of 47 cm x 78 cm. In addition to the map proper, collateral information concerning the map production is also printed on the background of the map in five languages. The color of the hemispheric map fields is a combination of a bright light yellow and light grey/green, all the lettering being black. 2. PRODUCTION BASIS The Mercury Map project continued the close scientific cooperation between the Moscow State University for Geodesy and Cartography (MIIGAiK), Russia, and the Institute for Cartography of the Dresden University of Technology (TUD), Germany. Since the main purpose of the maps of this series is the high-accuracy depiction of its overall relief, we were looking for an adequate representation. A "classical" shaded-relief representation was chosen like the one already used for the other maps of the series. At MIIGAiK a pencil-made manual hill-shaded Mercury relief was prepared. It assumes an illumination from the west with an elevation angle equal/smaller to 400. So far, this pencil drawing appears to be the most impressive depiction of the geomorphologic features of the planet: highlands and lowlands, mountains and valleys etc. are very clearly and spontaneously perceivable. Thus one can obtain a good impression of relief details of the entire planet Mercury, and, hence, simultaneously get an idea of its physiognomy as a whole. The overall drawing quality, the richness in detail and the original size of the shading suggested a final map scale of 1: 17 800 000. It was, however, not possible to use the relief drawing at once without some additional work because of its smaller scale, plus/minus 1000 in longitude and various compositions of chosen maps. This original depiction was part of the "Atlas of Terrestrial Planets and their Moons" published in 1992 [4]. Still today there exists no relief information about approximately 60% of Mercury’s surface. In this connection, the only evidence for this part of the planet surface are the Albedo features [5] displayed in the Mercury Albedo Map (Figure 1). Figure 1. Mercury Albedo Map (taken from the “Atlas of Terrestrial Planets and their Moons”) The other difference consists of shaded relief shown on one hemisphere only. The reasons mentioned above suggest that the cartographic depiction has to be separated in such a way. This means that on each hemisphere we have about a quarter of the planet’s area covered by a shaded-relief representation (Figure 2). Figure 2. Mercury: areas with shaded-relief depiction It was necessary to recompile the available maps, then to divide the shaded-relief information into two hemispheres and finally “recover” them by the Albedo layer. This layer displays three intensity classes. All these operations were accomplished by the program "GeoGraph, 2.0". (License number 003932). 3. MAP DESIGN AND PRODUCTION The discussion about the map scale was a lengthy and difficult one. Based on the final decision that the final map scale had to be “unround” - which resulted in a diameter of the two hemispheres of approx. 40 cm - a first general map layout was made. Soon it became clear that it would be advisable to print all the collateral information about the planet Mercury not on the front side but rather put it into text blocks in the back. For the production process conventional reprographic methods were applied, using a repro screen of 54 points/cm for the relief shading original. Some attempts were made in order to optimise the reproduction of the relief representation, in particular to balance between the bright tones of the highlands and the darker tones of the lowlands. The coordinate grid of the map whose geometry is based on the Transversal Equivalent Azimuth Projection of Lambert shows every twentieth parallel and meridian. The lettering displays different fonts: for craters 7-point Arial, capital letters; for mountain ranges 7-point Arial Italic, capital letters; for plains 7-point Arial, wide spacing, capital letters; for landing sites 7-point, Arial. Thus, it gives explanations on all known and named geographic features. The type of lettering allows deducing the geomorphological categories. Below the title "Mercury", between the two hemispheres, one finds the astronomical/astrological symbol for this planet. For the printing three colours have been used. All letterings have been printed in black. The background of the whole is kept in "night-blue", representing the darkness of the outer space and using special printing ink. The paper format of the map is 55 cm x 84 cm, the format of the printed area being 47 cm x 78 cm which corresponds to the hemisphere diameter. The printed area in the back amounts to 43 cm x 81.5 cm. This is the size of a frame which contains explanatory texts about the map and the planet. The front side also comprehends collateral information about map designer, printer, editor, cartographers and consultants.