Issue with geographic to topocetric projection

[yuvalg1987]

Hi,
I'm trying to move from a geographic projection into a topocentric one. I found the following proj4 line that does the trick but can't seem to get it running using pyproj. What am I missing? how should I create this new CRS?

BTW I'm new to proj4/pyproj so I might just misunderstanding the basic concept. I'm trying to use geopandas to_crs() method using the proj4 line for the ocnversion.

+proj=pipeline \
    +step +proj=cart +ellps=WGS84 \
    +step +proj=topocentric +ellps=WGS84 +lon_0=5 +lat_0=55 +h_0=200

Thanks
Yuval

[snowman2]

See: OSGeo/PROJ#2444

Do you have PROJ 8+?

[yuvalg1987]

Thanks for the suggestion. I'll try it asap. What alternative to geopandas do I have for reading a .shp file and performing this type of operation?

[yuvalg1987]

Ok, using the Transformer seems to work correctly and you're probably right regarding geopandas/geopandas#1175 so I guess geopandas is not the way to go for this. Thanks for the help!

[snowman2]

@yuvalg1987 does this work with geopandas?

src_crs = CRS("+proj=cart +ellps=WGS84")
dst_crs = CRS("+proj=topocentric +ellps=WGS84 +lon_0=5 +lat_0=55 +h_0=200")
gdf.set_crs(src_crs)
gdf2 = gdf.to_crs(dst_crs)

[yuvalg1987]

No, Didn't work. I think it has to do with the fact that this is a custom combination that cannot be solved by the default configuration of PROJ4.

[snowman2]

That's unfortunate. Good luck 👍

[stefangachter]

Dear all, I am also stuck with the topocentric conversion. I am using pyproj version 3.1.0, assuming that the above mentioned pull request #2444 is included. If I follow the example, https://proj.org/operations/conversions/topocentric.html,

import pyproj
pipe_trans = pyproj.Transformer.from_pipeline("+proj=pipeline +step +proj=cart +ellps=WGS84 +step +proj=topocentric +ellps=WGS84 +lon_0=5 +lat_0=55 +h_0=200")

then I get an error
ProjError("Invalid projection b'+proj=pipeline +step +proj=cart +ellps=WGS84 +step +proj=topocentric +ellps=WGS84 +lon_0=5 +lat_0=55 +h_0=200'.: (Internal Proj Error: proj_create: Error -5 (unknown projection id): Pipeline: Bad step definition: proj=topocentric (unknown projection id))")
indicating that topocentric conversion is unknown as a projection. Do I have to define it not as a transformation? If yes, can you provide and example?

[stefangachter]

Do you mean that it is an issue of pyproj under Windows? If yes, how much time does it take to fix it? No, I haven’t tested with conda. Guidelines how to that?

[snowman2]

Do you mean that it is an issue of pyproj under Windows?

It means that the Windows wheels have an older version of PROJ packaged inside. The easiest solution would be to wait for the next release coming soon.

For conda, see: https://pyproj4.github.io/pyproj/stable/installation.html

[stefangachter]

Thanks. I followed the instruction. I installed miniconda and pyproj with
conda install -c conda-forge pyproj
But then I run Anaconda's python, then I run into the following problem:

>>> import pyproj
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "D:\Documents\Programs\Miniconda3\lib\site-packages\pyproj\__init__.py", line 49, in <module>
    import pyproj.network
  File "D:\Documents\Programs\Miniconda3\lib\site-packages\pyproj\network.py", line 10, in <module>
    from pyproj._network import (  # noqa: F401
ImportError: DLL load failed while importing _network: 指定されたモジュールが見つかりません。

I followed the instructions at #770 but installing the Microsoft Visual C++ Redistributables did not solve my issue.

[stefangachter]

Ah, it is about settings. If I using anaconda's python from within Visual Studio, then it cannot find the DLLs, but the using it from within Anaconda's power shell, then it is fine:

(base) PS C:\Users\gstef> python
Python 3.9.5 (default, May 18 2021, 14:42:02) [MSC v.1916 64 bit (AMD64)] :: Anaconda, Inc. on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import pyproj
>>> pyproj.__proj_version__
'8.1.0'
>>> pipe_trans = pyproj.Transformer.from_pipeline("+proj=pipeline +step +proj=cart +ellps=WGS84 +step +proj=topocentric +ellps=WGS84 +lon_0=5 +lat_0=55 +h_0=200")
>>> pipe_trans
<Other Coordinate Operation Transformer: pipeline>
Description: PROJ-based coordinate operation
Area of Use:
- undefined
>>>

Thus, with package from conda, the version is correct.

[stefangachter]

Ok, I could make it run with miniconda and Visual Studio 2019. Finally....

>>> import pyproj
>>> pyproj.__proj_version__
'8.1.0'
>>> pipe_trans = pyproj.Transformer.from_pipeline("+proj=pipeline +step +proj=cart +ellps=WGS84 +step +proj=topocentric +ellps=WGS84 +lon_0=5 +lat_0=55 +h_0=200")
>>> pipe_trans
<Other Coordinate Operation Transformer: pipeline>
Description: PROJ-based coordinate operation
Area of Use:
- undefined
>>>