[OSRS-PROJ] Lambert Conformal Conic 1SP

[Gerald I. Evenden]

Aye!  That was a nasty one.  One suggestion that might have helped
is to try the -V option and look at the final list of options
that proj decides to use.

I reiterate that this problem shows the need for certification
tables usable in testing projection programs.  That is, a list of
geographic coordinates and their corresponding cartesian space
values for the worlds grid systems.  How this list can be used
with individual projection packages will, of course, vary, but
at least a list would be available and individual software can
can be constructed to use the definition data to test the
software.

As for testing the PROJ.4 system I would be glad to assist in
any way.

On Sat, 2003-02-08 at 23:52, Frank Warmerdam wrote:
> Gerald I. Evenden wrote:
> > I compiled and loaded PROJ on my RedHat Linux system, edited your
> > email into a script and executed it:
> > 
> > proj +proj=lcc +lat_1=18 +lat_0=18 +lon_0=-77 +k_0=1 +x_0=250000
> > +y_0=150000 +ellps=clrk66 +units=m <<EOF
> > 76d56'37.26"W 17d55'55.80"N
> > EOF
> > 
> > produces:
> > 
> > 255966.58       142493.51
> > 
> > These numbers seem to match the JAD69 / Jamaica National Grid
> > numbers in the referred to web page.
> > 
> > You seem to have a flawed version of proj.
> 
> Gerald,
> 
> Thanks for trying this out.  Seeing that you were getting the
> correct results I was able to dig in deeper and figure out what
> was happening differently.  It turns out that if proj finds the
> proj_def.dat file, then it will pick up a default lat_2 value
> of 45 from it, and this is what screws up the results.
> 
> The proj_def.dat file contains:
> 
> <lcc> # Conterminous U.S. map
> lat_1=33
> lat_2=45
> <>
> 
> For my purposes it is sufficient to add the +no_defs item on
> the commandline to supress the default values.
> 
> So in summary, for LCC1SP  use +lat_0 and +lat_1, and make sure that
> the no_defs flag is used to avoid including any default parameters.
> 
> Best regards,


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