[QGIS-ZA-user] CRS Trouble - EPSG:4326 -->EPSG:2048

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[QGIS-ZA-user] CRS Trouble - EPSG:4326 -->EPSG:2048

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Hi List

This is not really a QGIS specific question/ issue, just that I am trying to achieve something within QGIS.

The Case:
I have data (geopackage attached) with crs WGS84, EPSG:2643 which I have gone through hoops and loops to no avail, to re-project to EPSG:2048. The result I am getting is to the effect that the data is flipped over the equator.

An workarounds/ methodology / pointers to something I am missing?

PS: I have worked through shapefiles, geopackage and PostGIS...same result.

Thanks
Erick.

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| @erickndava | http://erickndava.github.io/ |

Thou art my hiding place; thou shalt preserve me from trouble; thou shalt compass me about with songs of deliverance. Selah. Psalm 32:7

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Re: CRS Trouble - EPSG:4326 -->EPSG:2048

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Hi Erick,
The CRS of the data is currently EPSG:4326 ie WGS84 Decimal Degrees.

If you Use the Export --> Save Feature As... option and from the CRS options select ZANGI HBKNO19, it ought to solve the problem.
EPSG 2048 is the conventional South Oriented projection system. There has been some recent discussion on the forum on this.topic and one needs to first analyse the projection information for any data one receives (it should be standard practice to do this in any case to confirm that the CRS of any data does indeed appear to be what has been defined.

Trust this helps
Regards
Neil Falconer

On Wed, Mar 27, 2019 at 1:10 AM E. Ndava via qgis-za-user <[hidden email]> wrote:
Hi List

This is not really a QGIS specific question/ issue, just that I am trying to achieve something within QGIS.

The Case:
I have data (geopackage attached) with crs WGS84, EPSG:2643 which I have gone through hoops and loops to no avail, to re-project to EPSG:2048. The result I am getting is to the effect that the data is flipped over the equator.

An workarounds/ methodology / pointers to something I am missing?

PS: I have worked through shapefiles, geopackage and PostGIS...same result.

Thanks
Erick.

--
----------------------------------------------------------------------------------------------------------------------------------------
| @erickndava | http://erickndava.github.io/ |

Thou art my hiding place; thou shalt preserve me from trouble; thou shalt compass me about with songs of deliverance. Selah. Psalm 32:7
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Re: CRS Trouble - EPSG:4326 -->EPSG:2048

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Hi Erick

On 27 Mar 2019, at 01:09, E. Ndava via qgis-za-user <[hidden email]> wrote:

Hi List

This is not really a QGIS specific question/ issue, just that I am trying to achieve something within QGIS.

The Case:
I have data (geopackage attached) with crs WGS84, EPSG:2643

you mean 4326

which I have gone through hoops and loops to no avail, to re-project to EPSG:2048. The result I am getting is to the effect that the data is flipped over the equator.

That’s perfectly correct and to be expected. 2048 is south-facing (wsu or west south up). If you want a north-facing or east north up one use ‘ZANGI HBKNO19’.

There are a bunch of new SA CRSs in the latest EPSG database that duplicate the south facing ones that were already there and add north facing variants (so the ZANGI ones can be retired). However they have issues: 102482 (should match 2048 but it doesn’t. It uses k=-1 which does the wrong thing and is deprecated) and 102562 (same effect as ZANGI HBKNO19 except 102562 uses k=1 which does nothing and is deprecated). So I would avoid using the new ones.

Gavin



An workarounds/ methodology / pointers to something I am missing?

PS: I have worked through shapefiles, geopackage and PostGIS...same result.

Thanks
Erick.

--
----------------------------------------------------------------------------------------------------------------------------------------
| @erickndava | http://erickndava.github.io/ |

Thou art my hiding place; thou shalt preserve me from trouble; thou shalt compass me about with songs of deliverance. Selah. Psalm 32:7
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Re: CRS Trouble - EPSG:4326 -->EPSG:2048

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Erick, further to my previous response

On 27 Mar 2019, at 01:09, E. Ndava via qgis-za-user <[hidden email]> wrote:

The result I am getting is to the effect that the data is flipped over the equator.

The data are not flipping over the equator. Instead, the axes are flipping (so N and S are swapped)


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Re: CRS Trouble - EPSG:4326 -->EPSG:2048

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Thanks Neil and Gavin.

Will give the ZANGI HBKNO19 a go once I get to my machine. 

Actually saw an earlier thread on ZANGI HBKNO19 but the content/ scope flew over my head. This problem is motivation to delve CRSs further. 

Thanks for this explanation "
The data are not flipping over the equator. Instead, the axes are flipping (so N and S are swapped)".

Thanks again. 
Erick. 

On Wed, 27 Mar 2019, 09:47 Gavin Fleming via qgis-za-user, <[hidden email]> wrote:
Erick, further to my previous response

On 27 Mar 2019, at 01:09, E. Ndava via qgis-za-user <[hidden email]> wrote:

The result I am getting is to the effect that the data is flipped over the equator.

The data are not flipping over the equator. Instead, the axes are flipping (so N and S are swapped)

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