[Proj] request help with Lambert Conic Conformal (2SP)

[Rick Graves]

Mikael and Carl,

From the correct shape file, the point touching the bounding box on the Eastern side is 2345137.5423228294, 1430204.1095800549.  Comparing these with numbers from proj with the lat/long inputs, the easting is within 0.1%, and the northing is within 1%, which I believe is close enough (for points picked from on line maps).

Mikael wrote:

> you could try this Proj.4 definition: +init=epsg:2992

The following two return the exactly same numbers when I input -116.463726 45.614818:

proj +proj=lcc +lon_0=-120.5 +lat_0=41.75 +lat_1=43.0 +lat_2=45.5 +x_0=400000 +y_0=0.0 +units=ft

proj +init=epsg:2992

Now I have to figure out how to merge the change file coordinates into the original file!

Thanks for solving the Lambert Conic Conformal (2SP) problem!

Rick



________________________________
 From: Mikael Rittri <Mikael.Rittri at carmenta.com>
To: PROJ.4 and general Projections Discussions <proj at lists.maptools.org> 
Sent: Thursday, August 16, 2012 6:42 PM
Subject: Re: [Proj] request help with Lambert Conic Conformal (2SP)
 

Carl,
In fact, I don't think you are missing anything. 

I made a quick back-of-an-envelope calculation - not using
proj, just a plain calculator - starting with the projection
origin, assuming 111120 meters per degree of latitude,
and 111120 * cos(lat) meters per degree of longitude.  

For the test point, I got 

Easting = 1408985 ft
Northing = 2341613 ft. 

That's close enough to your (Carl's) result, with my simple method. 

I may have made a mistake, but Rick: could you double-check your expected coordinates - I am pretty sure they are wrong. 

Regards,

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

16 aug 2012 kl. 05:30 skrev "Carl Godkin" <cgodkin at gmail.com>:



>
>
>On Wed, Aug 15, 2012 at 8:00 PM, Rick Graves <gravesricharde at yahoo.com> wrote:
>
>Hey,
>>
>>
>>The good news is that Oregon is the last one I need to get working.  The bad news is I do not have it working yet.
>>
>>
>>Here is the metadata from the .prj that I got from the state:
>>
>>
>>PROJCS["NAD_1983_Oregon_Statewide_Lambert_Feet_Intl",
>>GEOGCS["GCS_North_American_1983",
>>DATUM["D_North_American_1983",
>>SPHEROID["GRS_1980",6378137.0,298.257222101]],
>>PRIMEM["Greenwich",0.0],
>>UNIT["Degree",0.0174532925199433]],
>>PROJECTION["Lambert_Conformal_Conic"],
>>PARAMETER["False_Easting",1312335.958005249],
>>PARAMETER["False_Northing",0.0],
>>PARAMETER["Central_Meridian",-120.5],
>>PARAMETER["Standard_Parallel_1",43.0],
>>PARAMETER["Standard_Parallel_2",45.5],
>>PARAMETER["Latitude_Of_Origin",41.75],
>>UNIT["Foot",0.3048]],
>>VERTCS["NAD_1983",
>>DATUM["D_North_American_1983",
>>SPHEROID["GRS_1980",6378137.0,298.257222101]],
>>PARAMETER["Vertical_Shift",0.0],
>>PARAMETER["Direction",1.0],
>>
>>
>>I initialized proj as follows:
>>
>>
>>proj +proj=lcc +lon_0=-120.5 +lat_0=41.75 +lat_1=43.0 +lat_2=45.5 +x_0=1312335.958005249 +y_0=0.0 +units=ft
>>
>>
>>I assume something is not right.
>>
>>
>>
>>
>
>
>I think there are two things wrong:  
>1. Your false easting is here given in feet while I believe proj always wants meters.  The number is about 400000m.  (See http://trac.osgeo.org/proj/wiki/GenParms).
>2. You didn't include an ellipsoid or datum so I'm surprised that proj worked at all since I get an error without +datum=NAD83 or +ellps=GRS80.
>
>
>However, correcting both of those, I get  X=2344859.57 ft, Y=1434192.31 ft, which isn't what you want either.  
>
>
>Now I want to know what I am missing!  Let's hope someone cleverer than me answers.
>
>
>carl
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