CRS troubles (QGIS 3.6.3, Proj 6.1.0)

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CRS troubles (QGIS 3.6.3, Proj 6.1.0)

Hernán De Angelis-4
I am having difficulties using QGIS 3.6.3 with Proj 6.1.0. I wonder if
this can be a consequence of the recent integration with Proj 6 or may
be some other (local) problem.

The most striking issue after installing the new version is that many of
the usual projections are now either missing or have a different
authority name. The latter is not in itself a problem, but many of the
usual projections (EPSG:4326, EPSG:4258), including most of the ones I
used in my projects, are simply not present. Some of those  seem to have
been reinterpreted as user defined.

Has anyone experienced this?

Any hint will be appreciated.

Thanks

H.


For example, for EPSG 3006, used in some of these projects QGIS states:

Generated CRS (+proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0
+units=m +no_defs)

Extent

Extent not known

Proj4

+proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs


But doing ogrinfo about one of the layers in the project can be
retrieved correctly:

Layer SRS WKT:
PROJCS["SWEREF99 TM",
     GEOGCS["SWEREF99",
         DATUM["SWEREF99",
             SPHEROID["GRS 1980",6378137,298.257222101,
                 AUTHORITY["EPSG","7019"]],
             AUTHORITY["EPSG","6619"]],
         PRIMEM["Greenwich",0,
             AUTHORITY["EPSG","8901"]],
         UNIT["degree",0.0174532925199433,
             AUTHORITY["EPSG","9122"]],
         AUTHORITY["EPSG","4619"]],
     PROJECTION["Transverse_Mercator"],
     PARAMETER["latitude_of_origin",0],
     PARAMETER["central_meridian",15],
     PARAMETER["scale_factor",0.9996],
     PARAMETER["false_easting",500000],
     PARAMETER["false_northing",0],
     UNIT["metre",1,
         AUTHORITY["EPSG","9001"]],
     AXIS["Northing",NORTH],
     AXIS["Easting",EAST],
     AUTHORITY["EPSG","3006"]]


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proj 4 use degrees instead of grad

Julien_Guilloux
Hi list,

I would like to generate a polygon grid. The coordinate system i need is the old French NTF (with grad unit and Paris as first meridian).
No trouble, there is the espsg code: 4807. When looking description of 4807 in spatialrefsys, grad as unit are well indicate. So... all seem perfect.... but...

When i generate the shape grid, i notice that proj 4 consider the unit as degrees and not as grad !
That why the location of my generate shape is not good, with a difference exactly egal to a 0.9 factor (a circle in grad is 400g, a circle in degrees is 360°, so 1 grad = 0.9 degree)

Do proj 4 understand only degree coordinates ?
i try to make a personnal SRID but no success...

Thanks if you have any tip...

So long,
Julien

 
Julien-Pierre GUILLOUX

Parc national des Écrins
04 92 40 20 56 / 06 99 77 38 26
www.ecrins-parcnational.fr





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Re: proj 4 use degrees instead of grad

Kristian Evers-2

Julien,

 

Yes, PROJ 4 only understands degrees and radians (depending on how you interface with PROJ). However, PROJ 6 is also capable of understanding gradians. QGIS 3.8 is properly compatible with PROJ 6 so look out for that when it lands.

 

/Kristian

 

Fra: Qgis-user <[hidden email]> På vegne af Julien Guilloux
Sendt: 14. juni 2019 13:04
Til: qgis-user <[hidden email]>
Emne: [Qgis-user] proj 4 use degrees instead of grad

 

Hi list,

 

I would like to generate a polygon grid. The coordinate system i need is the old French NTF (with grad unit and Paris as first meridian).

No trouble, there is the espsg code: 4807. When looking description of 4807 in spatialrefsys, grad as unit are well indicate. So... all seem perfect.... but...

 

When i generate the shape grid, i notice that proj 4 consider the unit as degrees and not as grad !

That why the location of my generate shape is not good, with a difference exactly egal to a 0.9 factor (a circle in grad is 400g, a circle in degrees is 360°, so 1 grad = 0.9 degree)

 

Do proj 4 understand only degree coordinates ?

i try to make a personnal SRID but no success...

 

Thanks if you have any tip...

 

So long,

Julien


Billede fjernet af afsender.

  Billede fjernet af afsender.

Julien-Pierre GUILLOUX

Parc national des Écrins
04 92 40 20 56 / 06 99 77 38 26
www.ecrins-parcnational.fr

 

 


 


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Re: CRS troubles (QGIS 3.6.3, Proj 6.1.0)

Hernán De Angelis-4
In reply to this post by Hernán De Angelis-4
As a follow up on this I would like to add that this messsage:

proj_create: crs not found

pops up during both "make" and "make install".

This happens with both 3.6.2 and 3.6.3.


As before, any hint on what's going on and how to overcome it is welcome!

Thanks!

H.


On 2019-06-14 12:06, Hernán De Angelis wrote:

> I am having difficulties using QGIS 3.6.3 with Proj 6.1.0. I wonder if
> this can be a consequence of the recent integration with Proj 6 or may
> be some other (local) problem.
>
> The most striking issue after installing the new version is that many
> of the usual projections are now either missing or have a different
> authority name. The latter is not in itself a problem, but many of the
> usual projections (EPSG:4326, EPSG:4258), including most of the ones I
> used in my projects, are simply not present. Some of those  seem to
> have been reinterpreted as user defined.
>
> Has anyone experienced this?
>
> Any hint will be appreciated.
>
> Thanks
>
> H.
>
>
> For example, for EPSG 3006, used in some of these projects QGIS states:
>
> Generated CRS (+proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0
> +units=m +no_defs)
>
> Extent
>
> Extent not known
>
> Proj4
>
> +proj=utm +zone=33 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0 +units=m +no_defs
>
>
> But doing ogrinfo about one of the layers in the project can be
> retrieved correctly:
>
> Layer SRS WKT:
> PROJCS["SWEREF99 TM",
>     GEOGCS["SWEREF99",
>         DATUM["SWEREF99",
>             SPHEROID["GRS 1980",6378137,298.257222101,
>                 AUTHORITY["EPSG","7019"]],
>             AUTHORITY["EPSG","6619"]],
>         PRIMEM["Greenwich",0,
>             AUTHORITY["EPSG","8901"]],
>         UNIT["degree",0.0174532925199433,
>             AUTHORITY["EPSG","9122"]],
>         AUTHORITY["EPSG","4619"]],
>     PROJECTION["Transverse_Mercator"],
>     PARAMETER["latitude_of_origin",0],
>     PARAMETER["central_meridian",15],
>     PARAMETER["scale_factor",0.9996],
>     PARAMETER["false_easting",500000],
>     PARAMETER["false_northing",0],
>     UNIT["metre",1,
>         AUTHORITY["EPSG","9001"]],
>     AXIS["Northing",NORTH],
>     AXIS["Easting",EAST],
>     AUTHORITY["EPSG","3006"]]
>
>
> _______________________________________________
> Qgis-user mailing list
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> List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
> Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
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Re: CRS troubles (QGIS 3.6.3, Proj 6.1.0)

Nyall Dawson
In reply to this post by Hernán De Angelis-4
On Fri, 14 Jun 2019 at 20:06, Hernán De Angelis <[hidden email]> wrote:

>
> I am having difficulties using QGIS 3.6.3 with Proj 6.1.0. I wonder if
> this can be a consequence of the recent integration with Proj 6 or may
> be some other (local) problem.
>
> The most striking issue after installing the new version is that many of
> the usual projections are now either missing or have a different
> authority name. The latter is not in itself a problem, but many of the
> usual projections (EPSG:4326, EPSG:4258), including most of the ones I
> used in my projects, are simply not present. Some of those  seem to have
> been reinterpreted as user defined.
>
> Has anyone experienced this?

Looks like you've already solved your issue by moving to 3.8, but to
explain: QGIS 3.6 (and <= 3.4.8) have NO support for proj 6/GDAL 3.
Those combinations just won't work. 3.4.9 will run on proj 6/gdal 3,
but still uses the outdated proj 4 api calls.

For best results, use proj 6.1 and gdal 3.0 with QGIS master only
(3.8.0). It is fully supported, including all the wonderful
transformation improvements which Proj 6 brings.

Nyall
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Re: CRS troubles (QGIS 3.6.3, Proj 6.1.0)

Hernán De Angelis-4
On 2019-06-15 00:42, Nyall Dawson wrote:

> On Fri, 14 Jun 2019 at 20:06, Hernán De Angelis <[hidden email]> wrote:
>> I am having difficulties using QGIS 3.6.3 with Proj 6.1.0. I wonder if
>> this can be a consequence of the recent integration with Proj 6 or may
>> be some other (local) problem.
>>
>> The most striking issue after installing the new version is that many of
>> the usual projections are now either missing or have a different
>> authority name. The latter is not in itself a problem, but many of the
>> usual projections (EPSG:4326, EPSG:4258), including most of the ones I
>> used in my projects, are simply not present. Some of those  seem to have
>> been reinterpreted as user defined.
>>
>> Has anyone experienced this?
> Looks like you've already solved your issue by moving to 3.8, but to
> explain: QGIS 3.6 (and <= 3.4.8) have NO support for proj 6/GDAL 3.
> Those combinations just won't work. 3.4.9 will run on proj 6/gdal 3,
> but still uses the outdated proj 4 api calls.
>
> For best results, use proj 6.1 and gdal 3.0 with QGIS master only
> (3.8.0). It is fully supported, including all the wonderful
> transformation improvements which Proj 6 brings.

Thanks for your answer. Yes, I realized that afterwards nad just
installed master (3.8.0). It works very well.

Thanks for the great work!

/H.

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