0

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?

Improve this question
5
  • 1
    is that different from the EPSG:4293
    – nmtoken
    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
    – Jacques Strauss
    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
    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
    – Jacques Strauss
    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
    – Jacques Strauss
    Nov 27, 2020 at 7:09

1 Answer 1

Reset to default
1

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

Improve this answer

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.