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    EPSG reference

    EPSG:4700 — IGN Astro 1960

    IGN Astro 1960 (EPSG:4700) — a Geographic (degrees) system on the a=6378249.145 datum, used in Mauritania. Parameters, proj4, WKT, accuracy ±0.1 m, plus a free converter…

    At a glance

    EPSG
    4700
    Name
    IGN Astro 1960
    Kind
    Geographic (degrees)
    Family
    Geographic (longitude/latitude)
    Ellipsoid
    a=6378249.145
    Accuracy
    ±0.1 m (vs PROJ)
    Countries
    Mauritania
    Convert from this system now

    Area of use

    West-17.08°
    South14.72°
    East-4.80°
    North27.30°

    Projection parameters

    Projectionlonglat
    Semi-major axis6378249.145
    Inverse flattening293.465
    proj4
    +proj=longlat +a=6378249.145 +rf=293.465 +no_defs
    WKT (ESRI)
    GEOGCS["GCS_IGN Astro 1960",DATUM["D_Custom_6378249.145",SPHEROID["Custom_6378249.145",6378249.145,293.465]],PRIMEM["Greenwich",0],UNIT["Degree",0.0174532925199433],AUTHORITY["EPSG","4700"]]

    Sample conversion

    Mauritania capital: WGS84 -15.95820, 18.07350 → EPSG:4700 -15.9582000, 18.0735000

    Values are within ±0.1 m at the test point.

    About the Geographic (longitude/latitude) family

    IGN Astro 1960 is a geographic coordinate system: positions are longitude and latitude in degrees on its reference ellipsoid, not metres on a plane. It is the datum layer that projected grids (UTM, national belts) are built upon.

    Because it is unprojected, distances and areas cannot be measured directly from its degrees — convert to a metric projected system (or use a geodesic calculation) first. This page's converter does exactly that.

    Related systems

    Useful links: Converter · Batch converter · File converter · Country page

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    FAQ

    What is EPSG:4700?
    It is the coordinate system “IGN Astro 1960”, a Geographic (degrees) system in the Geographic (longitude/latitude) family, identified worldwide by the code EPSG:4700.
    What datum does it use, and how accurate is it?
    It is based on the a=6378249.145 ellipsoid with no default transform to WGS84 (ballpark). The residual at the test point is about ±0.1 m versus PROJ; for centimetre work use a geodetic adjustment service.
    Where is this system used?
    It is used in Mauritania. This page shows its area of use as a coordinate rectangle above.
    How do I convert EPSG:4700 to WGS84?
    Use the free coordinate converter above (preloaded with this system) to convert to WGS84, UTM, or any other system, within a ±0.1 m residual.

    You may also need: Arab-world coordinate converter · Surveying file format converter · Batch coordinate file converter