[OSGeo Africa] Kathu coordinate system

[Frank Sokolic]

Hi Hanlie,

If the survey was done in 1968 is it not possible that the units are in 
Cape feet? Not sure when surveyors switched to using metres. Are you 
able to post a scanned copy of the survey diagram?

Regards, Frank.

On 31/01/2014 09:58, Walter Smit wrote:
> OK, Gavin and I must have read the numbers too quickly...we were wrong.
>
> I have made some enquiries and apparently the mine surveyors in the area
> know of this system, but nobody is able to give its actual details. Waiting
> on some more replies from surveyors, who might have more details.
>
> Is it really necessary to convert the coordinates? Can you not rather "warp"
> the diagram itself to other known boundaries? I did this pretty successfully
> with diagrams from the 1830s using the georeferencing toolbar in "that other
> GIS package" and shapefiles of Farm Portions from the Surveyor General.
>
> -----Original Message-----
> From: africa-bounces at lists.osgeo.org [mailto:africa-bounces at lists.osgeo.org]
> On Behalf Of Walter Smit
> Sent: 30 January 2014 03:00 PM
> To: 'Africa local chapter discussions'
> Subject: Re: [OSGeo Africa] Kathu coordinate system
>
> I agree with Gavin...since it is from a surveyor and from pre-1999...
>
> -----Original Message-----
> From: africa-bounces at lists.osgeo.org [mailto:africa-bounces at lists.osgeo.org]
> On Behalf Of Gavin Fleming
> Sent: 30 January 2014 02:18 PM
> To: africa at lists.osgeo.org
> Subject: Re: [OSGeo Africa] Kathu coordinate system
>
> Looks like it's south-oriented transverse mercator with a central meridian
> of 23 and an offset of some nice round number > 3000000 on the SO x axis (or
> a local reference latitude) and it would likely be on the Cape datum. A bit
> of playing around these parameters will hopefully position it right.
>
> Does searching on the khathu system not turn up anything?
>
> On 30/01/2014 13:56, Hanlie Pretorius wrote:
>> Hi,
>>
>> I a hand-drawn survey diagram that I need to reproduce in QGIS. The
>> area is in the Northen Cape, close to the 23° E longitude.
>>
>> The diagram was done in 1968 and its coordinate system is specified as
>> 'Kathu System'. The y coordinates are given first, are all positive
>> and they range from about 23 000 to 49 000. The x coordinates are
>> given second and they range from +31 000 to -153 000.
>>
>> Can anyone tell me what the specifications for this coordinate system
>> would be? I.e. the information I would need to create a WKT or proj4
>> specification for the CRS.
>>
>> Thanks
>> Hanlie
>> _______________________________________________
>> Africa mailing list
>> Africa at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/africa
>
>
> --
> regards
>
> Gavin
>
> Gavin Fleming
> http://afrispatial.co.za
> t: 0218630660
> c: 0845965680
> f: 0866164820
>