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    EPSG reference

    EPSG:22991 — Egypt 1907 / Blue Belt

    Egypt 1907 / Blue Belt (EPSG:22991) — a Projected (metres) system on the helmert datum, used in Egypt. Parameters, proj4, WKT, accuracy ±4.3 m, plus a free converter to…

    At a glance

    EPSG
    22991
    Name
    Egypt 1907 / Blue Belt
    Kind
    Projected (metres)
    Family
    Transverse Mercator (belt)
    Ellipsoid
    helmert
    Accuracy
    ±4.3 m (vs PROJ)
    Countries
    Egypt
    Convert from this system now

    Area of use

    West33.00°
    South21.97°
    East36.95°
    North31.36°

    Projection parameters

    Projectiontmerc
    Latitude of origin30
    Central meridian35
    Scale factor1
    False easting300000
    False northing1100000
    Ellipsoidhelmert
    Unitsm
    Helmert shift to WGS84-130,110,-13,0,0,0,0
    proj4
    +proj=tmerc +lat_0=30 +lon_0=35 +k=1 +x_0=300000 +y_0=1100000 +ellps=helmert +units=m +no_defs +towgs84=-130,110,-13,0,0,0,0
    WKT (ESRI)
    PROJCS["Egypt 1907 / Blue Belt",GEOGCS["GCS_Egypt 1907 / Blue Belt",DATUM["D_Helmert_1906",SPHEROID["Helmert_1906",6378200,298.3],TOWGS84[-130,110,-13,0,0,0,0]],PRIMEM["Greenwich",0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",300000],PARAMETER["False_Northing",1100000],PARAMETER["Central_Meridian",35],PARAMETER["Scale_Factor",1],PARAMETER["Latitude_Of_Origin",30],UNIT["Meter",1],AUTHORITY["EPSG","22991"]]

    Sample conversion

    Centre of the area of use: WGS84 34.97500, 26.66500 → EPSG:22991 297346.638, 730384.811

    Values are within ±4.3 m at the test point.

    About the Transverse Mercator (belt) family

    Egypt 1907 / Blue Belt is a Transverse Mercator belt — a national or cadastral grid in metres, conformal (angles are preserved), with its own central meridian and scale factor. Egypt's Red/Purple/Blue belts, the Levant grids, and many Gulf cadastral systems are of this kind.

    Two things decide whether your coordinates land correctly: the exact belt (central meridian) and the datum. Mixing a coordinate from one belt into another, or ignoring the datum shift to WGS 84, is the usual cause of a systematic offset in imported survey data.

    Related systems

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    FAQ

    What is EPSG:22991?
    It is the coordinate system “Egypt 1907 / Blue Belt”, a Projected (metres) system in the Transverse Mercator (belt) family, identified worldwide by the code EPSG:22991.
    What datum does it use, and how accurate is it?
    It is based on the helmert ellipsoid and it carries Helmert parameters to WGS84. The residual at the test point is about ±4.3 m versus PROJ; for centimetre work use a geodetic adjustment service.
    Where is this system used?
    It is used in Egypt. This page shows its area of use as a coordinate rectangle above.
    How do I convert EPSG:22991 to WGS84?
    Use the free coordinate converter above (preloaded with this system) to convert to WGS84, UTM, or any other system, within a ±4.3 m residual.

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