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    EPSG reference

    EPSG:30491 — Voirol 1875 / Nord Algerie (ancienne)

    Voirol 1875 / Nord Algerie (ancienne) (EPSG:30491) — a Projected (metres) system on the clrk80ign datum, used in Algeria. Parameters, proj4, WKT, accuracy ±0.1 m, plus a…

    At a glance

    EPSG
    30491
    Name
    Voirol 1875 / Nord Algerie (ancienne)
    Kind
    Projected (metres)
    Family
    Lambert Conformal Conic
    Ellipsoid
    clrk80ign
    Accuracy
    ±0.1 m (vs PROJ)
    Countries
    Algeria
    Convert from this system now

    Area of use

    West-2.22°
    South34.64°
    East8.64°
    North37.14°

    Projection parameters

    Projectionlcc
    Standard parallel 136
    Latitude of origin36
    Central meridian2.7
    Scale factor0.999625544
    False easting500000
    False northing300000
    Ellipsoidclrk80ign
    Unitsm
    Helmert shift to WGS84-73,-247,227,0,0,0,0
    proj4
    +proj=lcc +lat_1=36 +lat_0=36 +lon_0=2.7 +k_0=0.999625544 +x_0=500000 +y_0=300000 +ellps=clrk80ign +units=m +no_defs +towgs84=-73,-247,227,0,0,0,0
    WKT (ESRI)
    PROJCS["Voirol 1875 / Nord Algerie (ancienne)",GEOGCS["GCS_Voirol 1875 / Nord Algerie (ancienne)",DATUM["D_Clarke_1880_IGN",SPHEROID["Clarke_1880_IGN",6378249.2,293.4660212936269],TOWGS84[-73,-247,227,0,0,0,0]],PRIMEM["Greenwich",0],UNIT["Degree",0.0174532925199433]],PROJECTION["Lambert_Conformal_Conic"],PARAMETER["False_Easting",500000],PARAMETER["False_Northing",300000],PARAMETER["Central_Meridian",2.7],PARAMETER["Standard_Parallel_1",36],PARAMETER["Scale_Factor",0.999625544],PARAMETER["Latitude_Of_Origin",36],UNIT["Meter",1],AUTHORITY["EPSG","30491"]]

    Sample conversion

    Algeria capital: WGS84 3.05880, 36.75380 → EPSG:30491 532274.263, 383775.619

    Values are within ±0.1 m at the test point.

    About the Lambert Conformal Conic family

    Voirol 1875 / Nord Algerie (ancienne) uses the Lambert Conformal Conic projection — a cone-based, angle-preserving grid well suited to territories that stretch east–west, defined by one or two standard parallels. It is common for national mapping and for oil-and-gas grids across North Africa and Arabia.

    Scale is true along the standard parallel(s) and grows away from them; for precise distance work reduce ground distances to grid using the point scale factor. Confirm both standard parallels and the datum before trusting imported coordinates.

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    FAQ

    It is the coordinate system “Voirol 1875 / Nord Algerie (ancienne)”, a Projected (metres) system in the Lambert Conformal Conic family, identified worldwide by the code EPSG:30491.

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