any know how to convert

New York Long Island State Plane Coordinate System (FIPS 3104) Feet,
North American Datum 1983 (NAD83). The approximate ranges of coordinate
values for the City are:

X-coordinate (East-West): minimum: 909900; maximum: 1067600
Y-coordinate (North-South): minimum: 117500; maximum: 275000

to longitude and latitude?

i need exact step by step formula or a written PHP function/library
that take in the x,y coordinate and outputs the lat/long

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Request for Question Clarification by pafalafa-ga on 20 Jul 2005 12:49 PDT

Phew!

I'm moderately semi-literatre in GIS matters, but you've really posed a toughie.

The Army Corps of Engineers makes available a free software package
that will supposedly make just the sort of conversion you're asking
for:


http://crunch.tec.army.mil/software/corpscon/corpscon.html


Even if the software can crank out your conversions, it still would
leave open the question of exactly what algorithm was used to
translate coordinates.

Note that there's a link to a FAQs page, and some discussion there of
lat/long (including some odd sign reversal cautions).

Hope it's of some help.  Let me know if it looks useful.


pafalafa-ga

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Clarification of Question by realestate_guru-ga on 20 Jul 2005 13:35 PDT

i am actually aware of that however we are looking either

1. the exact step by step formula so we can implement it in PHP
2. the exact php implementtation in a function of library

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Request for Question Clarification by pafalafa-ga on 01 Aug 2005 07:19 PDT

I have located some resources that I believe will provide you the
information you need to either use and existing program or create a
new program for the conversion you need.

However, given the inherent complexity of the task, I thought I would
post the resources here for your review before providing a final
answer.

Please have a look at these links, and let me know if they do the trick:


An article from 2004 describing the State Plane system, and coversion
tools that are available:

http://web.archive.org/web/20040328045921/http://www.profsurv.com/ps_scripts/article.idc?id=1180
NGS Geodetic Toolkit, Part 7: Computing State Plane Coordinates




Numerous detailed publications on State Plane conversions are available here:


http://www.ngs.noaa.gov/PUBS_LIB/pub_index.html
National Spatial Reference System: Datums, Networks, Coordinate Systems 



the above site includes links to:


State Plane Coordinate System of 1983 - NOAA Manual NOS NGS 5 
http://www.ngs.noaa.gov/PUBS_LIB/ManualNOSNGS5.pdf


Understanding the State Plane Coordinate Systems
http://www.ngs.noaa.gov/PUBS_LIB/UnderstandingSPC.pdf


The State Coordinate Systems (A Manual for Surveyors) SP 235
http://www.ngs.noaa.gov/PUBS_LIB/publication235.pdf


State Plane Coordinates by Automatic Data Processing SP 62-4
http://www.ngs.noaa.gov/PUBS_LIB/publication62-4.pdf
[NOTE:  this is a giant document -- 60+ Mb -- and provides the
equations and constants needed for converting from State Plane to
Lat/Long.  Actual state-by-state parameters are included in a table at
the back of the document.  If you want to work directly from
conversion formulas, this is the reference you will need]



As far as actual programs, there is both an online conversion program
as well as downloadable source code available:


The "Tools" page here:

http://www.ngs.noaa.gov/TOOLS/spc.shtml
State Plane Coordinates


includes:


Interactive Conversions 
SPC -> Latitude/Longitude 
http://www.ngs.noaa.gov/cgi-bin/spc_getgp.prl

and


PC Program 
SPCS83 
http://www.ngs.noaa.gov/PC_PROD/SPCS83/


which leads to the following options:


==========
http://www.ngs.noaa.gov/PC_PROD/SPCS83/

PC Software Download - SPCS83

Converts NAD 83 state plane coordinates to NAD 83 geographic positions
and conversely. Includes defining constants for NAD 83 coordinate
zones. State plane coordinates are entered or computed to 1 mm
accuracy, while the latitudes and longitudes entered or computed
correspond to approximately 0.3 mm accuracy.


An on-line interactive version is also available from the Geodetic Tool Kit. 

Download the PC executable

View the User's Guide.

Download a ZIP'ed archive of the SPCS83 executable, FORTRAN source,
and user's guide.
==========



Another program which seems to more directly target Lat/Long conversions is here:


==========
http://www.ngs.noaa.gov/PC_PROD/GPPCGP/

PC Software Download - GPPCGP

Converts NAD 27 State plane coordinates to NAD 27 geographic positions
(latitudes and longitudes) and conversely. Includes defining constants
for all NAD 27 plane coordinate zones.

Download the PC executable

View the program documentation.

Download a ZIP'ed archive of the GPPCGP FORTRAN source code, and
sample files.[24.7 KB].

Download a ZIP'ed archive of the GPPCGP executable, FORTRAN source,
and sample files.[96.3 KB].
==========




I am quite certain that you can either use these tools directly to
make the conversions you need, or alternatively, use them to write a
program to make the conversions.


Please review these links and let me know how well they meet your
needs, and what other sort of information you need to make for a
complete answer to your question.

Thanks...and best of luck.


pafalafa-ga

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Request for Question Clarification by pafalafa-ga on 01 Aug 2005 07:37 PDT

Forgot to mention that the "Tools" page also includes this helpful tidbit:


For more information about the State Plane Coordinate System contact:
The National Geodetic Survey Information Services Branch
phone: (301) 713-3242; Fax:(301) 713-4172 


They might be able to assist you with any programming challenges that arise.

I think your answer is on the following link:
http://www.uwgb.edu/dutchs/UsefulData/UTMFormulas.HTM

HTH