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<div class="moz-cite-prefix">Hi Gavin,<br>
<br>
Your point 1 below<br>
The only time I have ever seen TMSO as per "1d" below (ie: the
actual numeric columns of a coordinate list swopped) is in the
early days of ReGIS .<br>
This caused havoc, and I presumed that the reason the ReGIS guys
did it, was a confusion of the Survey coordinate naming
convention.<br>
<br>
To put it in the simplest terms:<br>
Cartesian 'okes called it XY and survey 'okes call it YX - but in
a coordinate list format, the 1st column is East/West, and the
second column is North/South - regardless of whether that column
is called X or Y.<br>
<br>
Point 2 - no idea what form ArcGIS uses<br>
<br>
Point 3 - Surveyor conventions:<br>
It would be better to simply look at the coordinate lists printed
on any SG General Plan or Diagram.<br>
Such coordinates from a surveyor, in electronic form, might
already have been altered to suit some software package.<br>
The coordinates printed on a survey diagram are the definitive
ways surveyors use their coordinates. ie:<br>
<br>
<table width="75%" border="1" cellpadding="2" cellspacing="2">
<tbody>
<tr>
<td valign="top">Name<br>
</td>
<td valign="top">Y<br>
</td>
<td valign="top">X<br>
</td>
</tr>
<tr>
<td valign="top">A<br>
</td>
<td valign="top">0.0000000003128453</td>
<td valign="top">3098441.7473872434347868</td>
</tr>
<tr>
<td valign="top"><br>
</td>
<td valign="top"><br>
</td>
<td valign="top"><br>
</td>
</tr>
</tbody>
</table>
<br>
(without as many decimal places)<br>
<br>
As you can see: 1st column for "left-right" value, and second
column for "up-down" value.<br>
<br>
Hope this helps, and that my point of view is correct.<br>
<br>
Regards,<br>
Zol<br>
<br>
<br>
<br>
On 2013/09/03 14:16, Gavin Fleming wrote:<br>
</div>
<blockquote cite="mid:5225D32A.50502@afrispatial.co.za" type="cite">Hi
all
<br>
<br>
We are adding some predefined north-oriented SACRS definitions to
QGIS so that we can all easily use the normal "LO" GIS data and
not have to 'roll our own' custom CRS definitions, which should
make everyone's lives easier.
<br>
<br>
The proj4 South-oriented (TMSO) definitions from the EPSG that are
in QGIS 2 (all the 'Lo' Hartebeesthoek and Cape ones) are correct
according to the EPSG but I would like to establish whether
everyone follows the EPSG axis-order convention in South Africa.
If the norm is to NOT follow the axis order conventions, then the
proj4 definitions need to be altered.
<br>
<br>
1. Look at the alternatives for the point below. Say whether you
consider c or d to represent how you obtain and use TMSO
coordinates:
<br>
<br>
a. Here is a WKT point in EPSG:4326
<br>
<br>
POINT(23 -28) Axis order is x,y
<br>
<br>
b. This is the same point in what we GIS users in SA would call
colloquially 'LO23' (i.e. north facing SACRS)
<br>
<br>
POINT(-0.0000000003128453 -3098441.7473872434347868) Axis order
is x,y
<br>
<br>
c. This is the same point in EPSG:2050 (SACRS) with EPSG
axis-order convention (y,x)
<br>
<br>
POINT(0.0000000003128453 3098441.7473872434347868) Axis order is
y,x
<br>
<br>
d. This is the same point in EPSG:2050 (SACRS) with what I think
is South African axis-order convention (x,y)
<br>
<br>
<font color="#cc0000">POINT(3098441.7473872434347868
0.0000000003128453) Axis order is x,y
<br>
</font><br>
2. Can anyone tell me what axis order ArcGIS expects TMSO
coordinates to be in?
<br>
<br>
3. Please send a small sample of data that you *know* is in TMSO.
e.g. some raw land surveyors data.
<br>
<br>
If you've read this far I'd be grateful for a quick response to 1,
2 and 3.
<br>
<br>
</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
===========================================
Zoltan Szecsei PrGISc [PGP0031]
Geograph (Pty) Ltd.
P.O. Box 7, Muizenberg 7950, South Africa.
65 Main Road, Muizenberg 7945
Western Cape, South Africa.
34° 6'16.35"S 18°28'5.62"E
Tel: +27-21-7884897 Mobile: +27-83-6004028
Fax: +27-86-6115323 <a class="moz-txt-link-abbreviated" href="http://www.geograph.co.za">www.geograph.co.za</a>
===========================================</pre>
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