[OSGeo Africa] Getting ancient SG diagrams into GIS

[Aslam Parker]

Hi 

The 1904 and 1912 diagrams will be in local coordinate systems. You need to identify the accuracy of the coordinates that is required in GIS. 

I would advise you to get the spatial data from the SG and see if you can relate the diagrams to that. It would be a good initial approximation of the property of the dimensions of the SG spatial data corresponds to the diagrams

If you require very accurate, you need to employ the services of a Land Surveyor who will search adjacent properties or the e-records of the Surveyor General for modern coordinates in the national control survey network.

-----Original Message-----
From: Africa [mailto:africa-bounces at lists.osgeo.org] On Behalf Of Sindile Bidla
Sent: 18 November 2015 12:43 PM
To: Africa local chapter discussions
Cc: Hanlie Pretorius
Subject: Re: [OSGeo Africa] Getting ancient SG diagrams into GIS

Dear Henlie,

What I sometimes do is to see if I can relate an old diagram to its adjacent properties and perform geo-referencing  - but obviously this is also dependent on your use case. I would then make a note of such on my data.

Please also do send the diagrams.

Sindile Bidla

On 2015/11/18 12:26 PM, Hanlie Pretorius wrote:
> Hi,
>
> A client of mine has sent me 6 SG diagrams dating from 1904 to 1912 
> and wants me to get them into GIS.
>
>  From my previous experience these will be using a local coordinate 
> system that needs to be converted to a modern coordinate system that 
> GIS and I understand. Since I'm not trained as a surveyor, this is 
> beyond my capabilities.
>
> One of the diagrams has a note that refers to a 1998 consolidation 
> diagram that I found on the SG site, but it doesn't help me at all, 
> looking at the 2014 farm data that I have.
>
> Is anyone on the list perhaps willing to help me with this? If so, I 
> can send you the diagrams and the coordinates on them in Excel format.
>
> Thanks
> Hanlie
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