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considered. For this purpose booklets, placards, 
calendars, separate photos and brochures should 
be used. 
The scheme marks out three levels of 
cartographic information support. They are 
related first of all to the area of coverage and 
namely global, regional and local. The first level 
includes small-scale mapping, the second - 
mapping of separate regions and the third one - 
mapping of separate local sites on large scales. 
Consequently we relate the creation of globes 
and demonstration wall maps to the first level, 
and complex mapping and surface modeling - to 
the second and third ones. We consider the 
scales of 1:2,000,000, 1:500,000, 1:100,000 and 
1:25,000 to be the major scales. Mapping on a 
scale of 1:2,000,000 provides for the updating 
of the already compiled map. 
It should be reminded that the updating of this 
map in particular was among the tasks of the 
surveys planned for the Mars Observer station. 
As it is known, its flight has not provided the 
expected results, however, it will be possibly 
repeated in 1996. Regarding the MARS-96 
mission, its information is also supposed to be 
used for updating the map on a scale of 
1:2,000,000. In addition these data are 
considered for regional mapping on scales of 
1:500,000 and 1:100,000 and for thematic 
mapping as well. 
The Atlas of Mars is included at every level. We 
consider this publication to consist of three 
parts. The first part is the review containing the 
general information about the planet and small- 
scale maps. The second part should be dedicated 
to the information about the regions and the 
third one - to separate local sites (both reference 
and anomalous). 
We have begun to create the Atlas of Mars, Part 
I. The maps will be plotted in separate sheets 
collected in a portfolio. Numbering of sections 
allows adding sheets in a section as far as new 
information becomes available. That is of 
especial importance for the sections containing 
various thematic maps. Preliminary the 
following sections will be included in this Part: 
479 
introduction, geographical maps (surface map, 
basic map for thematic mapping and 
hypsometric map), geophysical, geochemical, 
geological, morphological and climatological 
maps, maps of the surface physical properties 
and others. 
The first Part of the Atlas presents various 
thematic information characterizing the planet as 
a whole. This data is given in a small-scale map 
chosen as a unique basic map to show the entire 
planetary surface in a single sheet without 
breaks. The scale of 1:40,000,000 has been 
specified for the basic map. Choice of this scale 
is explained by the aspect that a scale of 
1:20,000,000 was used for an analogous basic 
map in the prepared for publication "Complex 
Atlas of the Moon". Consequently comparison 
of certain characteristics becomes easier, 
because these maps have the same dimensions. 
Additionally the scale chosen is convenient for 
the reference desktop usage. 
Regarding the projection, the equivalent elliptic- 
al Mollweide projection was chosen. Also the 
same choice as for the Atlas of the Moon. 
In general to present the surface of a celestial 
body as a whole in small-scale maps we usually 
use classic pseudocylindrical equivalent projec- 
tions. The Sanson (sinusoidal) projection and 
the  Mollweide (elliptical) projection are 
concerned first of all. The Sanson projection 
preserves length along the mean meridian and 
along all parallels. The other meridians of this 
projection's normal grid excluding the rectilinear 
mean one, are sinusoids. For Mollweide 
projection it is typical to preserve length along 
the equator. The meridians at +90° from the 
mean one are shown by a circle. The other 
meridians are presented by ellipses with one 
constant semi-axis and the other semi-axes 
varying (Gazetteer..., 1988). The latter depends 
on the longitude. Both projections are 
symmetrical. 
The Sanson sinusoidal projection and its 
modification (the Ekkert projection) are 
convenient for the presentation of the near- 
equatorial zones. However, from the +60° lati- 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996