[ncl-install] Installation of PROJ.4 and GDAL libraries

[Arturo Fernandez]

Hi Dave,
Sorry that I forgot to follow up as several things required my attention 
over the weekend. I had no problem building PROJ. as static & dynamic 
libraries, and after it GDAL and NCL. Everything looked fine. However, I 
cannot guaranteed that this NCL feature is working because I haven't tested 
it. It was more about including this feature during the system 
configuration in case someone is interested in it than an actual need. Next 
month I'll perform more testing on graphic environments and will let you 
know if the tests exhibit any problem or potential enhancement.
Thanks,
Arturo 
Dave Allured - NOAA Affiliate wrote:
Arturo, I think it will be okay to build PROJ.4 as shared/dynamic, rather 
than static.
Now I see another problem with proj. GDAL 3.2.1 wants to use proj 7, but I 
think that NCL 6.6.2 has a fixed dependency on proj.4. It appears to be a 
single dependency in ncarg/ni/src/lib/nfp/TransformCoordinate.c. It is 
possible that proj 7 will satisfy this dependency without any changes, but 
I have not verified that. This would be worth testing, and let us know if 
it works.
If not, then you might need to install two proj versions together, and deal 
with possible conflicts in some way. If proj 7 can satisfy that single 
dependency, then you will need only proj 7, and there will be no conflicts. 
So that would be best if you can get it to work. I think this proj version 
problem is already solved by other packagers such as epel and macports, but 
I do not know how they did it.
GDAL version 3 reduced the number of external libraries required by 
default. Therefore I think you can remove many of those --without flags if 
you want to. NCL uses GDAL to read only a limited subset of file formats, 
such as shapefiles, so only a limited set of --with flags are needed. NCL 
contains its own drivers for popular formats like netcdf, hdf4/5, and grib; 
these are not wanted from GDAL.
On Wed, Feb 24, 2021 at 10:55 AM Arturo Fernandez via ncl-install 
<ncl-install at mailman.ucar.edu <mailto:ncl-install at mailman.ucar.edu> > 
wrote:
Hello,
The NCL guide instruct to build the PROJ.4 ibraries as static and, after 
it, configure GDAL with "--with-static-proj4=/usr/local". Just for 
clarification, I'm using versions 7.2.1 and 3.2.1, respectively (using the 
master branches would also be feasible). Anyway, my questions are:
1) Is building PROJ.4 as a static library still mandatory?
2) Are there any changes in the flags to build GDAS? I would guess not but 
want to double check.
Thanks.
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