MAPS SHOWING GEOLOGY, OIL AND GAS FIELDS, AND GEOLOGICAL 
   PROVINCES OF AFRICA - GEOGRAPHIC COORDINATES 
   (AVAILABLE ONLINE AT GREENWOOD.CR.USGS.GOV)"

1. Reason for this publication

   Original CD-ROM (OF 97-470A) users have found the mismatch between  
Robinson projection in ARC/INFO and both ARCVEW and MAPINFO
(equal to scale factor of  about 1.16). 
By the time of publication we could not find that mismatch since there was
no 'Projector' extension in ARCVIEW and we were not MAPINFO users. 
That is why we have selected Robinson as the world projection for our data.

ARC/INFO itself correctly projects Robinson data to any other projection. 
Therefore there is no any problems to use original data for ARC/INFO users.
To resolve mismatch for ARCVIEW and MAPINFO users we have
decided to provide them with the same data set in Geographic coordinates.


2. Data set contains seven coverages in ARC/INFO export format without
  compression.  These are:
     2.1 geo2_7g   - Surficial geology. Item "glg" in Feature Attribute
     2.2 prov2_7g - Geological Provinces that outline areas with
                             common geological structures and petroleum systems.
                             There are two additional items in FAT:
                            "code" - Geologic Province code and
                            "name" - Geologic Province name.
      2.3 fld2_7     - Centerpoints of Oil and Gas fields.
      2.4 pol2_7    - Country boundaries.
      2.5 llf2_7      - Latitude/Longitude grid with cell size 4 * 6 degree.
      2.6 reg_2_7  - Boundary between region 2 (Middle East/North Africa
                              and 7 (Sub Saharan Africa).
      2.7 anno2_7 - annotations for Ocean names.

3. Covert any of these files to ARCVIEW shape files by IMPORT utility.
    Add legend files afr_age.avl from CD-ROM.

3. Please, use original metadata file on CD-ROM for further information.