[QGIS-ZA-user] Coordinate conversion from Cape Datum Lo27? to EGS 84

[Gavin Fleming]

Hi Jordan and thanks FC

I’m not sure how FC did the projection / transformation but you can use QGIS, proj or a number of other tools.

An issue to be aware of is that no GIS will do an accurate datum transformation from Cape to WGS84/Hartebeeshoek94 since there are different errors all over the country, as much as 300m. If you need accuracy, rather speak to a land surveyor, who can do a local transformation taking into account the known errors. 

Gavin

> On 22 Mar 2024, at 09:25, Jordaan Fouche via qgis-za-user <qgis-za-user at lists.osgeo.org> wrote:
> 
> Thank you FC, what software did you use to do the transformation?
>  
> Could you explain in a bit more detail?
>  
> Jordaan Fouche
> Portion 11
> Van Reenen Country Estate
> Van Reenen
> 3372
> Republic of South Africa
>  
> Tel: +27 (0)82 555 4227
>  
> From: FC Basson <FC.Basson at westerncape.gov.za <mailto:FC.Basson at westerncape.gov.za>> 
> Sent: Thursday, March 21, 2024 8:26 PM
> To: qgis-za-user at lists.osgeo.org <mailto:qgis-za-user at lists.osgeo.org>
> Cc: j.fouche9 at gmail.com <mailto:j.fouche9 at gmail.com>
> Subject: Re: [QGIS-ZA-user] Coordinate conversion from Cape Datum Lo27? to EGS 84
>  
> Just a slight edit to the Google Maps link:
> https://maps.app.goo.gl/VVS9XDfhjp88dXw97 <https://maps.app.goo.gl/VVS9XDfhjp88dXw97>
>  
> And if you prefer OSM:
> https://www.openstreetmap.org/?mlat=-26.82808180999955&mlon=28.591287809999518#map=12/-26.8281/28.5913 <https://www.openstreetmap.org/?mlat=-26.82808180999955&mlon=28.591287809999518#map=12/-26.8281/28.5913>
>  
>  
> From: qgis-za-user <qgis-za-user-bounces at lists.osgeo.org <mailto:qgis-za-user-bounces at lists.osgeo.org>> on behalf of FC Basson via qgis-za-user <qgis-za-user at lists.osgeo.org <mailto:qgis-za-user at lists.osgeo.org>>
> Sent: 21 March 2024 20:09
> To: qgis-za-user at lists.osgeo.org <mailto:qgis-za-user at lists.osgeo.org> <qgis-za-user at lists.osgeo.org <mailto:qgis-za-user at lists.osgeo.org>>
> Cc: FC Basson <FC.Basson at westerncape.gov.za <mailto:FC.Basson at westerncape.gov.za>>; j.fouche9 at gmail.com <mailto:j.fouche9 at gmail.com> <j.fouche9 at gmail.com <mailto:j.fouche9 at gmail.com>>
> Subject: Re: [QGIS-ZA-user] Coordinate conversion from Cape Datum Lo27? to EGS 84
>  
> I was able to locate the farm and can confirm that the coordinate should be in LO 29.  
> <image001.png>
> For GIS purposes, we use the rotated coordinate system, so the coordinates should be X: -40600, Y: -2968350, which converts to geographic coordinate of Lat: -26.828082, Lon: 28.591288, if you assume the input datum is Cape.  And here is a link to the location in Google Maps: https://maps.app.goo.gl/bEwU4pMa35Db2gpNA <https://maps.app.goo.gl/bEwU4pMa35Db2gpNA>
>  
> Regards
>  
> FC Basson
>  
>  
> From: qgis-za-user <qgis-za-user-bounces at lists.osgeo.org <mailto:qgis-za-user-bounces at lists.osgeo.org>> on behalf of Jordaan Fouche via qgis-za-user <qgis-za-user at lists.osgeo.org <mailto:qgis-za-user at lists.osgeo.org>>
> Sent: 21 March 2024 17:14
> To: qgis-za-user at lists.osgeo.org <mailto:qgis-za-user at lists.osgeo.org> <qgis-za-user at lists.osgeo.org <mailto:qgis-za-user at lists.osgeo.org>>
> Cc: j.fouche9 at gmail.com <mailto:j.fouche9 at gmail.com> <j.fouche9 at gmail.com <mailto:j.fouche9 at gmail.com>>
> Subject: [QGIS-ZA-user] Coordinate conversion from Cape Datum Lo27? to EGS 84
>  
> Have a set of old borehole data that I wish to plot in QGIS.
>  
> They were clearly drilled pre 1994 (Hartebeesthoek) and I am really struggling to plot them on QGIS. I suspect they may be Cape Datum.
>  
> The example that I am including is on the farm Rietvley 600 in the Balfour district.
>  
> The coordinates are legible as X:2968350;Y: 40600.
>  
> Can somebody please help me.
>  
>  
> Jordaan Fouche
> Portion 11
> Van Reenen Country Estate
> Van Reenen
> 3372
> Republic of South Africa
>  
> Tel: +27 (0)82 555 4227
>  
> "All views or opinions expressed in this electronic message and its attachments are the view of the sender and do not necessarily reflect the views and opinions of the Western Cape Government (the WCG). No employee of the WCG is entitled to conclude a binding contract on behalf of the WCG unless he/she is an accounting officer of the WCG, or his or her authorised representative.
> The information contained in this message and its attachments may be confidential or privileged and is for the use of the named recipient only, except where the sender specifically states otherwise.
> If you are not the intended recipient you may not copy or deliver this message to anyone."
> "All views or opinions expressed in this electronic message and its attachments are the view of the sender and do not necessarily reflect the views and opinions of the Western Cape Government (the WCG). No employee of the WCG is entitled to conclude a binding contract on behalf of the WCG unless he/she is an accounting officer of the WCG, or his or her authorised representative. 
> The information contained in this message and its attachments may be confidential or privileged and is for the use of the named recipient only, except where the sender specifically states otherwise. 
> If you are not the intended recipient you may not copy or deliver this message to anyone."
> _______________________________________________
> qgis-za-user mailing list
> qgis-za-user at lists.osgeo.org <mailto:qgis-za-user at lists.osgeo.org>
> https://lists.osgeo.org/mailman/listinfo/qgis-za-user <https://lists.osgeo.org/mailman/listinfo/qgis-za-user>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-za-user/attachments/20240402/584dbd7f/attachment-0001.htm>