Help wit .prj file

[AlaskanTides]

I am trying to create a Local projection in US Survey Feet.

I have pulled out the parameters from Trimble Buisness Center ...


Coordinate System Definition



Projection:

Plane


Origin latitude:  N68°03'52.04629"
Origin longitude:  W162°50'03.47958"
False northing:  142169.282 ft
False easting:  586270.569 ft
Scale factor:  1.0000000000
Parallel 1:  ?
Parallel 2:  ?
Shift grid name:  None


Azimuth:


System:  North
Coordinate direction:  North-East


Datum Transformation (To WGS84):


Method:  None
Translation X:  ?
Translation Y:  ?
Translation Z:  ?
Rotation X:  ?
Rotation Y:  ?
Rotation Z:  ?
Scale factor:  ?
Ellipsoid:  World Geodetic System 1984
Semi major axis:  20925604.474 ft
Flattening:  1 / 298.2572229329
Datum grid name:  None
Latitude grid file name:  None
Longitude grid file name:  None
Height grid file name:  None


Local site settings:


Project latitude:  ?
Project longitude:  ?
Project height:  0.000 ft
Ground scale factor:  1.0000000000
False northing offset:  0.000 ft
False easting offset:  0.000 ft


Geoid Model:


Name:  None
File:  None



Horizontal Site Calibration:


Translation north:  58.703 ft
Translation east:  -47.026 ft
Rotation:  0°46'36"
Origin north:  138673.296 ft
Origin east:  581961.364 ft
Scale factor:  1.0000000000


Vertical Site Calibration:


Shift at origin:  -0.063 ft
Slope North:  2.146 ppm
Slope East:  1.866 ppm
Origin north:  142169.253 ft
Origin east:  586270.535 ft


GNSS Vector Transformation Parameters:


Latitude deflection:  N0°00'00.00000"
Longitude deflection:  E0°00'00.00000"
Azimuth rotation:  0°00'00"
Scale factor:  1.0000000000


I have no experiance with creating a .prj so if you guys can help I would greatly appreciate it.

Pat

[AlaskanTides]

I am just trying to give this post a bump...... I know that there are a lot of gurus in here that can help me turn those parameters into a .prj. 

[AlaskanTides]

Ok I am bumping this Post again...... Here is the History of the projection I am fooling with. This Projection Started out as NAD27 ALASKA Zone 7 as obviously it predates 1983. Unfortunately This local system predates GPS Therefore This local Coordinate System I am working with is very similar to NAD27 but it missed the mark there by a bit as well... Im assuming this is because over the years error has been induced to the network ... For All I know the original survey was wrong...

Regardless What im trying to do is create a .prj file as close as i can to a site calibration that was done with my Trimble GPS.... The Parameters I posted above is what im shooting far.

This is my first attempt..... Any advice is appreciated. 

PROJCS["RED DOG MINE",GEOGCS["GCS_North_American_1927",DATUM["D_North_American_1927",SPHEROID["Clarke_1866",6378206.4,294.9786982]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",68.064457303],PARAMETER["Central_Meridian",-162.834299883],PARAMETER["scale_factor",1.0000],PARAMETER["false_easting",586270.569],PARAMETER["false_northing",142169.282],UNIT["Foot_US",0.30480060960121924]]

[AlaskanTides]

Updated to more Closely Match Trimble Site Calibration



PROJCS["RED DOG MINE",GEOGCS[""GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137,298.257223563]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",68.064457303],PARAMETER["Central_Meridian",-162.834299883],PARAMETER["scale_factor",1.0000],PARAMETER["false_easting",586270.569],PARAMETER["false_northing",142169.282],UNIT["Foot_US",0.30480060960121924]]


Im bumbling through this slowly but surely.... I hope its not a blunder that I listed the Semi Major Axis of the spheroid in meters as opposed to feet.

Since WGS_1984 is a standard perhaps it is looking for it that way. However I did not put an authority tag on it so im not sure.

[Alexey Pasumansky]

Hello Pat,

It seems that the initial information is not sufficient. Have you tried to modify the EPSG::26737 (NAD27 / Alaska zone 7) according to the parameters that you've got?

Code: [Select]

'PROJCS["NAD27 / Alaska zone 7 modified",
GEOGCS["NAD27",
DATUM["North American Datum 1927",
SPHEROID["Clarke 1866",6378206.4,294.978698213898,AUTHORITY["EPSG","7008"]],
TOWGS84[0,0,0,0,0,0,0],
AUTHORITY["EPSG","6267"]],
PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],
UNIT["degree",0.01745329251994328,AUTHORITY["EPSG","9102"]],
AUTHORITY["EPSG","4267"]],
PROJECTION["Transverse_Mercator",AUTHORITY["EPSG","9807"]],
PARAMETER["latitude_of_origin",68.064457303],
PARAMETER["central_meridian",-162.834299883],
PARAMETER["scale_factor",1],
PARAMETER["false_easting",586270.569],
PARAMETER["false_northing",142169.282],
UNIT["US survey foot",0.3048006096012192,AUTHORITY["EPSG","9003"]]]'

[ruyi7952]

This is a local coordinate system based on the TBC site calibration function.

use of the software's built-in local coordinate system, no need to define Prj elements...

If you must define it as a PRJ file, try the seven parameters [TOWGS84] or [FROMWGS84]. You need to use TGO v1.63 or other tools do it.

The main reason is that the Prj file can not well express the transformation relationship of TBC.

and

The frustrating thing is that often these coordinate systems, plane and elevation, are completely different coordinate systems.

I don't think Prj is a good idea.