[Proj] request help with Transverse_Mercator in proj

[Mikael Rittri]

Hello Rick,
I think you have just switched the values of x_0 and y_0, since x_0 should be False_Easting and y_0 should be False_Northing.

With Proj 4.8.0, I get

C:\Windows\System32>proj +proj=tmerc +lat_0=0 +lon_0=-90 +k=0.9996 +y_0=-4480000.0 +x_0=520000.0 -v

#Transverse Mercator
#       Cyl, Sph&Ell
# +proj=tmerc +lat_0=0 +lon_0=-90 +k=0.9996 +y_0=-4480000.0 +x_0=520000.0
# +ellps=WGS84

-92.88943290699996 45.64120292600006

294824.82       578245.14

which is at least near your expected result. (Maybe I made some other mistake.)

I would prefer to give the +ellps explicitly, but the default seems to be what you need, or nearly so.
(Not much difference between the WGS84 and the GRS_1980 ellipsoid.)

And I think +k_0 is now the recommended parameter name instead of +k, but it seems that +k still works.

Best regards,

Mikael Rittri
Carmenta
Sweden
http://www.carmenta.com

________________________________
From: proj-bounces at lists.maptools.org [mailto:proj-bounces at lists.maptools.org] On Behalf Of Rick Graves
Sent: Monday, August 13, 2012 3:42 AM
To: PROJ.4 Projections Discussions
Subject: [Proj] request help with Transverse_Mercator in proj

Hey,

Sorry to trouble you, but I still have a couple of states for which I need to get proj.4 working.  This time, it is Wisconsin.

I am starting with the Western most point in the state.  If you plug the following into maps.google.com, you will see it:

45.64120292600006, -92.88943290699996

I downloaded the shapefiles from the state web site.  In the shapefile, the minimum X point is this:

294822.7664999999, 578184.1052999999

Here is the metadata from the prj file:

PROJCS["NAD_1983_HARN_Wisconsin_TM",
GEOGCS["GCS_North_American_1983_HARN",
DATUM["D_North_American_1983_HARN",
SPHEROID["GRS_1980",6378137.0,298.257222101]],
PRIMEM["Greenwich",0.0],
UNIT["Degree",0.0174532925199433]],
PROJECTION["Transverse_Mercator"],
PARAMETER["False_Easting",520000.0],
PARAMETER["False_Northing",-4480000.0],
PARAMETER["Central_Meridian",-90.0],
PARAMETER["Scale_Factor",0.9996],
PARAMETER["Latitude_Of_Origin",0.0],
UNIT["Meter",1.0]]

I initialized proj as follows:

proj +proj=tmerc +lat_0=0.0 +lon_0=-90.0 +k=0.9996 +x_0=-4480000.0 +y_0=520000.0

When give proj this:

-92.88943290699996 45.64120292600006

I get this:

-4705175.18     5578245.14

But I am expecting this:

294822.7664999999, 578184.1052999999

I assume I am not initializing proj correctly.

If someone could spot my mistake, I would appreciate it.

Thanks,

Rick Graves

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