Trouble with Projection

[Shanton, James A]

Thank you very much for your help.   The county is now the correct size.
I did need to multiply the x_0 parameter by the feet conversion ratio.

Jim


-----Original Message-----
From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On
Behalf Of Ed McNierney
Sent: Friday, November 19, 2004 9:59 AM
To: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: Re: [UMN_MAPSERVER-USERS] Trouble with Projection

Jim -

Frank's making essentially the same suggestion I am, but I would recommend
you use his solution instead.  I had forgotten about that option and I
always think it's safer to use defined constants rather than numeric values
when you can - they're much less prone to typos!

        - Ed

-----Original Message-----
From: UMN MapServer Users List [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On
Behalf Of Frank Warmerdam
Sent: Friday, November 19, 2004 9:52 AM
To: MAPSERVER-USERS at LISTS.UMN.EDU
Subject: Re: [UMN_MAPSERVER-USERS] Trouble with Projection

Jim Shanton wrote:
> I'm trying to plot a property parcel shp file, and it keeps plotting
> in Pennsylvania instead of North Carolina.
...
>   PROJECTION
>
>      proj=lcc
>
>      lat_0=33.75              #Latitude of False Origin
>
>      lon_0=-79.0              #Longitude of Natural Origin (Central
> Meridian)
>
>      lat_1=34.33333333333334  #Latitude of First Standard Parallel
>
>      lat_2=36.16666666666666
>
>      x_0=2000000.002616666    # False Easting
>
>      y_0=0.0                  # False Northing
>
>      ellps=GRS80              # SPHEROID
>
>      a=6378137.0              # from SPHEROID
> ["GRS_1980",6378137,298.257222101]],
>
>      rf=298.257222101         #from SPHEROID
> ["GRS_1980",6378137,298.257222101]],
>
>      datum=NAD83
>
>   END
...
> UNIT["Foot_US",0.3048006096012192]]

Jim,

I think your main problem is the linear units.  The default units in
PROJ.4 is meters, but you need US feet.  Try adding a "units=us-ft"
in your PROJECTION declaration for the layer.  There is also some slight
chance you will need to alter the x_0 parameter by multiplying (or
dividing) by the meter/feet conversion ratio, but I doubt that will be
needed.

Good luck,

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