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I am using QGIS 3.16.

I would like to create a custom CRS using the following projection parameters:

Namibia Schwarzeck Projection Parameters:

Semi-major axis:    6 377 483.86500
Semi-minor axis:    6 356 078.96325
e2  0.006674372231
Inverse flattening: 299.152812800000
Shift X:    -616.80000
Shift Y:    -103.30000
Shift Z:    256.90000
Scale correction:   0.00000
Origin longitude:   17.00000
Origin latitude:    -22.00000
Scale factor:   1.00000
False easting:  1.00000
False northing: 0.00000

How do I go about it?

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  • 1
    is that different from the EPSG:4293
    – nmtoken
    Commented Nov 18, 2020 at 12:31
  • Seems like it isn't. Will use it to project unprojected dfx.CAD drawings. Thank you for your feedback Commented Nov 18, 2020 at 13:03
  • @JacquesStrauss Hello! Do you know of a government website that has this information. I'd like to add it to the EPSG / IOGP registry but I would need more information like a reference, is it used onshore only, etc.
    – mkennedy
    Commented Nov 20, 2020 at 3:14
  • Hi @mkennedy. I'm not exactly sure. But I acquired the parameters from lucasmbise.com/the-namibian-lo-coordinate-system... The only other government's institution I am aware of that offers geospatial data is digitalnamibia.nsa.org.na Commented Nov 27, 2020 at 7:06
  • I think it would be a great idea to contact the guys from nsa.org.na/page/gis-services Commented Nov 27, 2020 at 7:09

1 Answer 1

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It looks like Schwarzeck Lo/22/17: https://epsg.io/29377

False Easting should be: 0 and unit: GLM (German Legal Meter). You can also use meter as unit and use a scale factor of 1/GLM =0.9999864037

Here are the published PROJ.4 settings: (+proj=tmerc +lat_0=-22 +lon_0=17 +k=1 +x_0=0 +y_0=0 +axis=wsu +ellps=bess_nam +towgs84=616,97,-251,0,0,0,0 +to_meter=1.0000135965 +no_defs)

It is a south-orientated coordinate system. If your CAD system isn't set up like this just use a normal north-orientated transverse mercator projection (then don't use '+axis=wsu')

To use different datum transformation parameters +towgs84 must be changed to '+towgs84=616.8,103.3,-256.9,0,0,0,0'.

Here is some more information regarding Namibian map systems: https://www.africangeomatics.com/namibian-map-system

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