[Qgis-user] matching .prj (ArcGIS) with CRS in QGIS

[Andre Joost]

Am 31.05.2015 um 16:33 schrieb K Imran M:
> Dear Andre,
>
> Is it possible, because of the different WKT string specification, my shape
> files was misaligned for about 200 meters to 300 meters when I chose Kertau
> (RSO)/RSO Malaya (m) (EPSG:3168) as the projection (OTF)?

I have not tested the two versions to measure the offset, but generally 
the epsg and WKT definitions have no datum shift parameters. See this 
mailing list entry for possible values and background:

http://lists.maptools.org/pipermail/proj/2011-April/005656.html

> In view of that issue, can you advise me if I
> 1) can I still use the Kertau (RSO)/RSO Malaya (m) (EPSG:3168) projection?
> Or

This will not solve the datum shift issue.

> 2) should I transform the projection to any other projection?


Not a good idea, because the hotine oblique mercator is the right 
mathematical model for the projection.

  Or
> 3) should I use the User-define CRS? If yes, how can I do that?

This seems to be the best way:
- Copy the proj.4 string definition of EPSG:3168 to the clipboard
- Under Settings -> Custom CRS, fill in the string at the bottom
- add the datum shift +towgs84=-11,851,5,0,0,0,0
- give the CRS a good name
- click on the green to add it to the list
- delete the empty "new CRS" entry from the list
- click on Ok
- Rightclick on your layer, Set CRS for layer
- scroll to the bottom to get your custom CRS

HTH,
André Joost