EPSG Library · North Africa

EPSG:30791 — Nord Sahara 1959 / Nord Algerie

Source: EPSG Dataset via PROJ 9.5.1 · Updated 2026-10-05

Summary

EPSG:30791 (Nord Sahara 1959 / Nord Algerie) is a projected coordinate reference system on the Nord Sahara 1959 datum using the Lambert Conic Conformal (1SP) method, with coordinates in metres. Area of use: Algeria - onshore north of 38.

Type: projected
Datum: Nord Sahara 1959
Units: metre
Axes: X, Y

Definition

EPSG:30791 as published in the EPSG Dataset (PROJ 9.5.1).
Property	Value
EPSG code	EPSG:30791
Name	Nord Sahara 1959 / Nord Algerie
Type	Projected CRS
Datum	Nord Sahara 1959
Ellipsoid	Clarke 1880 (RGS) (a = 6,378,249.145 m, 1/f = 293.465)
Prime meridian	Greenwich
Projection method	Lambert Conic Conformal (1SP)
Axes	Easting (X, east, metre); Northing (Y, north, metre)
Scope	Engineering survey, topographic mapping.
Bounding box	-2.22° to 8.64° longitude, 34.64° to 37.14° latitude

Area of use

Algeria - onshore north of 38.5 grads North (34°39'N).

Projection parameters

Lambert Conic Conformal (1SP) parameters.
Parameter	Value	Unit
Latitude of natural origin	40	grad
Longitude of natural origin	3	grad
Scale factor at natural origin	0.999625544	unity
False easting	500,135	metre
False northing	300,090	metre

Example coordinates

A WGS 84 point at longitude 3.21°, latitude 35.89° (inside the area of use) has these coordinates in EPSG:30791:

Computed with PROJ using the EPSG default operation: unavailable until proj_trans is called.
Axis	Value	Unit
X	546,233.083	m
Y	287,994.766	m

At this point the projection scale factor is 0.99962738 and the grid convergence is +0.299770°.

Open this conversion in the coordinate converter

Transformations to WGS 84

Candidate operations from the EPSG Dataset, best first as ranked by PROJ.
Operation	Accuracy	Area of use
axis order change (2D) + Nord Sahara 1959 to WGS 84 (11) + axis order change (2D)	1 m	Algeria - onshore and offshore.
axis order change (2D) + Nord Sahara 1959 to WGS 84 (1) + axis order change (2D)	44 m	Algeria - onshore.
axis order change (2D) + Nord Sahara 1959 to WGS 84 (2) + axis order change (2D)	44 m	Algeria - onshore north of 32°N.
axis order change (2D) + Nord Sahara 1959 to WGS 84 (4) + axis order change (2D)	5 m	Algeria - District 3 (In Salah).
axis order change (2D) + Nord Sahara 1959 to WGS 84 (8) + axis order change (2D)	5 m	Algeria - Ahnet licence area.
axis order change (2D) + Nord Sahara 1959 to WGS 84 (7) + axis order change (2D)	5 m	Algeria - Hassi Mouina licence area.
axis order change (2D) + Nord Sahara 1959 to WGS 84 (5) + axis order change (2D)	100 m	Algeria - In Amenas block.
axis order change (2D) + Nord Sahara 1959 to WGS 84 (6) + axis order change (2D)	100 m	Algeria - Hassi Bir Reikaz.

Transformations change the datum, so each has an accuracy and an area of use. Choose the most accurate one that covers your data and record its name. See datum transformations.

Definitions and downloads

PROJ string

+proj=lcc +lat_1=36 +lat_0=36 +lon_0=2.7 +k_0=0.999625544 +x_0=500135 +y_0=300090 +a=6378249.145 +rf=293.465 +units=m +no_defs +type=crs

A PROJ string cannot carry every EPSG detail (axis order, datum ensemble, transformations). Prefer WKT2 or the EPSG code itself.

Proj4js definition used by the converter

+proj=lcc +lat_1=36 +lat_0=36 +lon_0=2.7 +k_0=0.999625544 +x_0=500135 +y_0=300090 +a=6378249.145 +rf=293.465 +units=m +towgs84=-267.407,-47.068,446.357,-0.179423,5.577661,-1.27762,1.204866 +no_defs

Datum shift from Nord Sahara 1959 to WGS 84 (11) (EPSG accuracy 1 m), the best single Helmert operation for this area of use. Where PROJ prefers a grid-based or multi-step operation (see the table above), results can differ by up to that operation's accuracy.

WKT2:2019

PROJCRS["Nord Sahara 1959 / Nord Algerie", BASEGEOGCRS["Nord Sahara 1959", DATUM["Nord Sahara 1959", ELLIPSOID["Clarke 1880 (RGS)",6378249.145,293.465, LENGTHUNIT["metre",1]]], PRIMEM["Greenwich",0, ANGLEUNIT["degree",0.0174532925199433]], ID["EPSG",4307]], CONVERSION["Nord Algerie", METHOD["Lambert Conic Conformal (1SP)", ID["EPSG",9801]], PARAMETER["Latitude of natural origin",40, ANGLEUNIT["grad",0.0157079632679489], ID["EPSG",8801]], PARAMETER["Longitude of natural origin",3, ANGLEUNIT["grad",0.0157079632679489], ID["EPSG",8802]], PARAMETER["Scale factor at natural origin",0.999625544, SCALEUNIT["unity",1], ID["EPSG",8805]], PARAMETER["False easting",500135, LENGTHUNIT["metre",1], ID["EPSG",8806]], PARAMETER["False northing",300090, LENGTHUNIT["metre",1], ID["EPSG",8807]]], CS[Cartesian,2], AXIS["easting (X)",east, ORDER[1], LENGTHUNIT["metre",1]], AXIS["northing (Y)",north, ORDER[2], LENGTHUNIT["metre",1]], USAGE[ SCOPE["Engineering survey, topographic mapping."], AREA["Algeria - onshore north of 38.5 grads North (34°39'N)."], BBOX[34.64,-2.22,37.14,8.64]], ID["EPSG",30791]]

Downloads

30791.prj — ESRI WKT for shapefiles
30791.wkt — OGC WKT2:2019

FAQ

What is EPSG:30791?

Where can EPSG:30791 be used?

Its area of use is: Algeria - onshore north of 38.5 grads North (34°39'N).

Is EPSG:30791 in metres or degrees?

EPSG:30791 is projected, so coordinates are easting and northing in metres, not degrees.

How do I convert EPSG:30791 to latitude and longitude?

Transform from EPSG:30791 to EPSG:4326 (WGS 84). In GeoCAD Bridge open the coordinate converter with EPSG:30791 preselected, enter easting and northing, and choose WGS 84 as the target.

How accurate is the transformation from EPSG:30791 to WGS 84?

The most accurate EPSG transformation listed here is “axis order change (2D) + Nord Sahara 1959 to WGS 84 (11) + axis order change (2D)”, with a stated accuracy of 1 m for Algeria - onshore and offshore.. Always check the area of use before applying it.

Coordinate systems

Articles

Tools

References

IOGP. EPSG Geodetic Parameter Dataset, epsg.org/crs_30791.
PROJ 9.5.1 / pyproj 3.7.2, used to compute every value on this page.

Cite this page

GeoCAD Bridge. “EPSG:30791 — Nord Sahara 1959 / Nord Algerie.” GeoCAD Bridge EPSG Library, updated 2026-10-05. https://www.geocadbridge.com/epsg/30791/