Downloading GIS Guiana Layers

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WARNING:

Most of the GIS Guiana layers are available and can be downloaded from this site ; new information layers will be put at disposal as the project will progress.

Downloadable information layers are linked with the themes tackled on this website and are a product of BRGM R&D activity: geochemistry, geophysics, mineral deposits, hydrography, etc. These information layers can be downloaded as ZIP files containing:

  • the files needed for a use with MapInfo® and ArcGIS® -V8 ;
  • an eventual short explanatory note and, when useful, a legend file.

    The access to some of the layers presented in this site is however restricted. This concerns:

  • layers/data which have not been initially generated by BRGM and for which a contract or license has been signed up with the supplier and
  • data which are usually sold by geological surveys throughout the world, being the result of their fundamental activity, such as geological mapping. In this case an hypertext link will redraw the visitor to the appropriate person to contact, either to buy the data or to negociate its use in a specific frame (e.g. research project with no commercial finality).

    Some of the layers, not generated by BRGM but freely accessible through the Web, have been put at disposal in order to help the visitor: e.g. DEM with various resolution from the NASA or the USGS. Satellites images presented on this site were also in free access on the Web. However, due to the huge size of the files, it was decided just to indicate the link towards the site where they can be downloaded.

    Some datafiles are may be too large to be downloaded by some users with low-rate Internet connection. Please note that file-size and date of creation or update are accessible by opening the zip file prior to download.

    The projection system is Universal Transverse Mercator - Zone 22N, for which the :
    - Reference meridian = - 51
    - Scale Factor = 0.99960
    - Reference Latitude = 0
    - False Easting = 500,000
    - False Northing = 0

    Datum CSG67, defined with the international ellipsoid of Hayford 1909:
    - great axis = 6,378,388 m
    - small axis = 6,356,911.9 m
    - f = 1/297
    with an offset of CSG67 compared to WGS84 of:
    - dX = -186 m
    - dY = 230 m
    - dZ = 110 m

    Data are provided in two formats, (1) MapInfo (.TAB) and (2) ESRI ArcGIS (.SHP). Vector layers contain associated tables from which information can be extracted (e.g. analytical results from geochemical prospecting). This allows users to process original data with their own parameters / software. Please note that georeferenced images available for download, have been processed with parameters which are not necessarily those convenient for you.