[OSGeo Africa] Identify coordinate system

Fri Jul 12 02:07:00 PDT 2019

Hi Zoltan.

Do you know approximately where  the shape file is supposed to be relative to other datasets?  Can you find common points between this unknown dataset and the others you have in that area?  If there is common data, you could try a helmert transformation which should give you all the various parameters (e.g. scale swing rotation…..) and you could manually input these for your data and see where it plots. If it matches your data, then you could just manually define it using your known dataset.  I assume there’s no metadata/xml file associated with the shapefile that can give a hint as to its origin also…?

If not, then happy hunting ☺

Regards
Abraham Parbhunath

[cid:imagef01a7a.JPG at d236f831.46a6b63d]<http://www.eskom.co.za/sites/idm/Residential/Pages/Residential0602-4556.aspx>
[cid:image380443.JPG at 81ec27f6.4fb748d0]<http://www.eskom.co.za> [cid:image4ba5a8.JPG at d88a807a.4eb92dc4] <http://www.facebook.com/EskomSouthAfrica>      [cid:image2c0a61.JPG at 63ad5af0.439f0677] <http://twitter.com/Eskom_SA>   [cid:imagef03896.JPG at 09ed4a42.4390579a] <http://www.instagram.com/eskom_hld_soc_ltd/>   [cid:imagedfe85b.JPG at 57a0c08b.47a07736] <http://www.youtube.com/user/EskomOfficialSite>

From: Africa <africa-bounces at lists.osgeo.org> On Behalf Of Zoltan Szecsei
Sent: Friday, 12 July 2019 09:12
To: africa at lists.osgeo.org
Subject: Re: [OSGeo Africa] Identify coordinate system

Hmmm....Ja.
But querying the source of the data might save all of us from getting a hard-earned 'Sherlock Holmes' badge :-)
On 2019/07/12 10:02, Hermanus Brynard wrote:
Zoltan
You mention 500k makes me think there could be a UTM transformation which usully adds a 500000m easting or westing and 10 000 000m northing to avoid negative numbers.

Can you send me the shapefile.
Manie

On Fri, Jul 12, 2019 at 8:57 AM Zoltan Szecsei <zoltans at geograph.co.za<mailto:zoltans at geograph.co.za>> wrote:
Hi Manie,
Thanks for the idea.

The current system in use is QND95 - the one you are suggesting  (I see) is from 1976, and its origin is "too close".
(Yes, I still tried it)

Looking at the numeric values of the coords, I am expecting something with an origin some 500Km West of Doha, and on the Equator.

And then of course I also need to consider the possibility that the coords in the shapefile are non-sensical, so I'm trying to find out its source....

Thanks and keep well,
Zoltan
On 2019/07/12 09:23, Hermanus Brynard wrote:
Zoltan
Have you tired the

Quatar National Grid <https://epsg.io/28600>
EPSG:28600<https://epsg.io/28600>

Manie Brynard

On Thu, Jul 11, 2019 at 6:33 PM Zoltan Szecsei <zoltans at geograph.co.za<mailto:zoltans at geograph.co.za>> wrote:
Hi Listers,
I've been asked o help a school-going daughter of a friend of mine in Doha (yes, this is "AfricaList" :-/  )
She has been given a shapefile without a projection file. The area is Al Wakrah, just South of Doha airport.

The numeric values of the geometry coords are around 560000, 2782000 - the second value looked like a distance from the Equator, so I tried UTM 39N
The scaling seems wrong, and it does not align with the coastline (QND95) shapefile I have.
(I also tried EPSG:27039)

As you can see, projection-sleuthing is not one of my strengths.
Can anyone point me in a direction to try and solve this?

Thanks in advance.

Kind regards,
Zoltan

--

=============================================

Zoltan Szecsei GPrGISc 0031

Geograph (Pty) Ltd.

GIS and Photogrammetric Services

P.O. Box 7, Muizenberg 7950, South Africa.

Mobile: +27-83-6004028

Qatar:  +974 5083 2722     www.geograph.co.za<http://www.geograph.co.za>

=============================================
_______________________________________________
Africa mailing list
Africa at lists.osgeo.org<mailto:Africa at lists.osgeo.org>
You can UNSUBSCRIBE at https://lists.osgeo.org/mailman/listinfo/africa

_______________________________________________

Africa mailing list

Africa at lists.osgeo.org<mailto:Africa at lists.osgeo.org>

You can UNSUBSCRIBE at https://lists.osgeo.org/mailman/listinfo/africa

--

=============================================

Zoltan Szecsei GPrGISc 0031

Geograph (Pty) Ltd.

GIS and Photogrammetric Services

P.O. Box 7, Muizenberg 7950, South Africa.

Mobile: +27-83-6004028

Qatar:  +974 5083 2722     www.geograph.co.za<http://www.geograph.co.za>

=============================================
_______________________________________________
Africa mailing list
Africa at lists.osgeo.org<mailto:Africa at lists.osgeo.org>
You can UNSUBSCRIBE at https://lists.osgeo.org/mailman/listinfo/africa

_______________________________________________

Africa mailing list

Africa at lists.osgeo.org<mailto:Africa at lists.osgeo.org>

You can UNSUBSCRIBE at https://lists.osgeo.org/mailman/listinfo/africa

--

=============================================

Zoltan Szecsei GPrGISc 0031

Geograph (Pty) Ltd.

GIS and Photogrammetric Services

P.O. Box 7, Muizenberg 7950, South Africa.

Mobile: +27-83-6004028

Qatar:  +974 5083 2722     www.geograph.co.za<http://www.geograph.co.za>

=============================================

Signature Version dd/mm/yyyy hh:mm
NB: This Email and its contents are subject to the Eskom Holdings SOC Ltd EMAIL LEGAL NOTICE which can be viewed at http://www.eskom.co.za/Pages/Email_Legal_Spam_Disclaimer.aspx
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/africa/attachments/20190712/b986adb8/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: imagef01a7a.JPG
Type: image/jpeg
Size: 71405 bytes
Desc: imagef01a7a.JPG
URL: <http://lists.osgeo.org/pipermail/africa/attachments/20190712/b986adb8/attachment-0006.jpe>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image380443.JPG
Type: image/jpeg
Size: 15193 bytes
Desc: image380443.JPG
URL: <http://lists.osgeo.org/pipermail/africa/attachments/20190712/b986adb8/attachment-0007.jpe>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image4ba5a8.JPG
Type: image/jpeg
Size: 11589 bytes
Desc: image4ba5a8.JPG
URL: <http://lists.osgeo.org/pipermail/africa/attachments/20190712/b986adb8/attachment-0008.jpe>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image2c0a61.JPG
Type: image/jpeg
Size: 12068 bytes
Desc: image2c0a61.JPG
URL: <http://lists.osgeo.org/pipermail/africa/attachments/20190712/b986adb8/attachment-0009.jpe>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: imagef03896.JPG
Type: image/jpeg
Size: 12420 bytes
Desc: imagef03896.JPG
URL: <http://lists.osgeo.org/pipermail/africa/attachments/20190712/b986adb8/attachment-0010.jpe>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: imagedfe85b.JPG
Type: image/jpeg
Size: 12621 bytes
Desc: imagedfe85b.JPG
URL: <http://lists.osgeo.org/pipermail/africa/attachments/20190712/b986adb8/attachment-0011.jpe>