[Proj] Proj Digest, Vol 157, Issue 4

[Chris Marsh]

Hi,

With +datum=wgs84 cs2cs does not work, regardless of the inclusion of +towgs

./cs2cs +proj=latlon +datum=WGS84 +to +proj=aea +lat_1=20 +lat_2=60
+lat_0=40 +lon_0=-96 +datum=wgs84 +units=m +no_defs
Using to definition: proj=aea lat_1=20 lat_2=60 lat_0=40 lon_0=-96
datum=wgs84 units=m no_defs
Rel. 4.9.3, 15 August 2016
<cs2cs>:
projection initialization failure
cause: unknown elliptical parameter name
program abnormally terminated

./cs2cs +proj=latlon +datum=WGS84 +to +proj=aea +lat_1=20 +lat_2=60
+lat_0=40 +lon_0=-96 +datum=wgs84 +units=m +no_defs +towgs84=0,0,0,0,0,0,0
Using to definition: proj=aea lat_1=20 lat_2=60 lat_0=40 lon_0=-96
datum=wgs84 units=m no_defs towgs84=0,0,0,0,0,0,0
Rel. 4.9.3, 15 August 2016
<cs2cs>:
projection initialization failure
cause: unknown elliptical parameter name
program abnormally terminated

Adding +towgs to the cs2cs works correctly:

./cs2cs +proj=latlon +datum=WGS84 +to +proj=aea +lat_1=20 +lat_2=60
+lat_0=40 +lon_0=-96 +ellps=GRS80 +units=m +no_defs +towgs84=0,0,0,0,0,0,0
-135.197151 60.52163
-2102114.41 2828965.44 0.00

Cheers
Chris


On 13 October 2017 at 17:17, Melita Kennedy <mkennedy2 at earthlink.net> wrote:

>
> Chris,
>
> Do you still get the error message if you change the output '+ellps=grs80'
> to '+datum=wgs84'? You also omitted the '+towgs84' parameter when you
> tested using cs2cs. The grs80 and wgs84 flattening are almost equal so I
> wonder if GDAL is doing some calculation connected to the '+towgs84'
> parameter using the grs80 and wgs84 ellipsoids incorrectly.
>
> Melita
>
> -----Original Message-----
>
> >Date: Fri, 13 Oct 2017 22:00:22 +0000
> >From: Chris Marsh <chris.marsh at usask.ca>
> >Subject: Re: [Proj] Failed to initialize PROJ.4 with "..."
> >To: PROJ.4 and general Projections Discussions
> >       <proj at lists.maptools.org>
> >
> >Hi,
> >
> >Thanks for the thoughts.
> >Yes ERROR 6 is the GDAL wrapper error.
> >
> >
> >On the computer that 'works':
> >cs2cs +proj=latlon +datum=WGS84 +to +proj=aea +lat_1=20 +lat_2=60
> +lat_0=40
> >+lon_0=-96 +ellps=GRS80 +units=m +no_defs
> >-135.197151 60.52163
> >-2102114.41 2828965.44 0.00
> >
> >On the computer that doesn't
> >
> >./cs2cs +proj=latlon +datum=WGS84 +to +proj=aea +lat_1=20 +lat_2=60
> >+lat_0=40 +lon_0=-96 +ellps=GRS80 +units=m +no_defs
> >-135.197151 60.52163
> >-2102114.41 2828965.44 0.00
> >
> >So that seems like that works....
> >
> >Would this point to GDAL being 100% the culprit?
> >
> >Cheers
> >Chris
> >
> >On 13 October 2017 at 21:23, Kristian Evers <kreve at sdfe.dk> wrote:
> >
> >> Chris,
> >>
> >> The "ERROR: 6" is GDAL. I am not sure if GDAL is forwarding the error
> code
> >> from PROJ.4, although I don't think so since PROJ.4 error codes are
> >> negative. This is why I want you to reproduce the problem just by using
> >> PROJ.4.
> >> Try running "cs2cs +proj=latlon +datum=WGS84 +to +proj=aea +lat_1=20
> >> +lat_2=60 +lat_0=40 +lon_0=-96 +ellps=GRS80 +units=m +no_defs" on the
> >> computer in question. If it fails the problem is definitely related to
> >> PROJ.4.
> >>
> >> Kristian
> >>
> >> ________________________________________
> >> Fra: proj-bounces at lists.maptools.org [proj-bounces at lists.maptools.org]
> >> p&#229; vegne af stevejking [stevejking at talktalk.net]
> >> Sendt: 13. oktober 2017 22:41
> >> Til: proj at lists.maptools.org
> >> Emne: Re: [Proj] Failed to initialize PROJ.4 with "..."
> >>
> >> Kristian,
> >> Is that a Proj4 error code?
> >>
> >> The Proj4 codes seem more specific. My reference says code 6 is
> "effective
> >> eccentricity = 1."
> >>
> >> Is it even a GDAL error code?
> >>
> >> Steve
> >>
> >>
> >> Kristian Evers-2 wrote
> >> > Chris,
> >> >
> >> > It would be beneficial if you could try to reproduce this problem just
> >> > using PROJ.4 and a few simple coordinates. Either on the command line
> >> with
> >> > a call to cs2cs or by a small C program. I tried initialising the
> >> > projection with a recent version of PROJ.4 without problems and I
> can't
> >> > see any obvious problem in the proj string. It is likely that if this
> >> > indeed is a bug in PROJ.4 that it has already been fixed.
> >> >
> >> > /Kristian
> >> >
> >> > ________________________________
> >> > Fra:
> >>
> >> > proj-bounces at .maptools
> >>
> >> >  [
> >>
> >> > proj-bounces at .maptools
> >>
> >> > ] p? vegne af Chris Marsh [
> >>
> >> > chris.marsh@
> >>
> >> > ]
> >> > Sendt: 13. oktober 2017 17:56
> >> > Til:
> >>
> >> > proj at .maptools
> >>
> >> > Emne: [Proj] Failed to initialize PROJ.4 with "..."
> >> >
> >> > Hi,
> >> >
> >> > ...
> >> >
> >> > ERROR 6: Failed to initialize PROJ.4 with `+proj=aea +lat_1=20
> +lat_2=60
> >> > +lat_0=40 +lon_0=-96 +x_0=0 +y_0=0 +ellps=GRS80 +towgs84=0,0,0,0,0,0,0
> >> > +units=m +no_defs'.
> >> >
> >> > ...Cheers
> >> > Chris
> >> >
> >> >
> >> >
> >> > _______________________________________________
> >> > Proj mailing list
> >>
> >> > Proj at .maptools
> >>
> >> > http://lists.maptools.org/mailman/listinfo/proj
>
>
>
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