# [Proj] State Plane Coordinate Zone 6 Conversion Help

Matt Bartolome mattxbart at gmail.com
Fri Feb 23 16:54:52 EST 2007

```Thanks Ed,
Ok. Specifying the wrong method was my first mistake. Now I've got:

\$ echo "6293409 1793361" | proj -I -f %.4f +proj=lcc +zone=26946
48.4666 0.5464

Spelling it out:
\$ echo "6262009 1854017" | proj -I -f %.4f +proj=lcc
+lat_1=33.88333333333333 +lat_2=32.78333333333333
+lat_0=32.16666666666666 +lon_0=-116.25 +x_0=2000000 +y_0=500000
-67.7015        35.2628

So something is still very wrong with what I'm doing. The agency I got
the data from confirmed it is the Lambert Method, GRS80 Spheroid,
NAD83 so I'm not sure what else to do.

-Matt

On 2/23/07, Ed McNierney <ed at topozone.com> wrote:
> Matt -
>
> You say you have "State Plane Zone 6" coordinates, but you're telling PROJ
> that they're UTM Zone 6 coordinates, and that's not at all the same thing.
> The California State Plane NAD83 projections are Lambert Conformal Conic
> projections, not UTM.
>
> I expect in your second example the lat_0 and lon_0 parameters are being
> ignored, since the UTM projection does not use those parameters.
>
> The EPSG code for NAD83 California Zone 6 is 26946, so you may want to just
> specify that as your input projection defintion, or spell it out:
>
> +proj=lcc +lat_1=33.88333333333333 +lat_2=32.78333333333333
> +lat_0=32.16666666666666 +lon_0=-116.25 +x_0=2000000 +y_0=500000
>
>      - Ed
>
> --
> Ed McNierney
> President and Chief Mapmaker
> Maps a la carte, Inc. / TopoZone.com
> 73 Princeton Street, Suite 305
> North Chelmsford, MA  01863
> Phone: (978) 251-4242
> Fax: (978) 251-1396
> ed at topozone.com
>
> > From: Matt Bartolome <mattxbart at gmail.com>
> > Reply-To: "PROJ.4 and general Projections Discussions"
> > <proj at lists.maptools.org>
> > Date: Fri, 23 Feb 2007 11:33:51 -0800
> > To: <proj at lists.maptools.org>
> > Subject: [Proj] State Plane Coordinate Zone 6 Conversion Help
> >
> > Hello list,
> >
> > I'm trying to convert state plane coordinates from zone 6 (san diego
> > county, california)  to latitude longitude and I'm having trouble.
> >
> > \$ echo "6262009 1854017" | proj -I -f %.4f +proj=utm +zone=6
> >
> > -100.1078       11.6424
> >
> > I've also tried plugging in some computed constants I found but I'm
> > not sure if they are accurate.
> >
> > \$ echo "6262009 1854017" | proj -I -f %.4f +proj=utm +ellps=GRS80
> > +zone=6 +lat_0=32.166667 +lon_0=-116.25 +datum=NAD83 +k=0.999954142490
> >
> > -100.1078       11.6424
> >
> > I'm pretty sure the datum NAD83 is correct, as well as the GRS80
> > ellipsoid. The values should be close to -116, 32.
> >
> > Thank you,
> > Matt
> > _______________________________________________
> > Proj mailing list
> > Proj at lists.maptools.org
> > http://lists.maptools.org/mailman/listinfo/proj
>
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```