[Xastir] Converting State GIS Maps

[Gerry Creager N5JXS]

If you look in the proj4 directory, you will find and EPSG file.  If you 
use +init=<appropriate epsg variable for datum> you'll get to the 
expected point.  NAD83 (2001 adjustment) is a datum, not a projection, 
as Tom indicated.

Gerry

Tom Russo wrote:
> On Wed, Mar 31, 2004 at 04:26:20PM -0500, a Mr. Richard Feyler of Fort Lee, New Jersey <dpg at coe.neu.edu> writes 'Dear Rosanne Rosannadanna':
> 
>>I know this is a little off topic, but with all this discussion about
>>maps, maybe the answer will be helpful for somebody else.
>>
>>I am trying to use the lovely, free ESRI maps from the Massachusetts GIS.
>>(www.state.ma.us/mgis). These are in MA State Plane coordinate system
>>(FIPS 2001), so I need to convert them using the shpcs2cs utility.
>>However, the syntax that I have been using is not working:
>>
>>shpcs2cs +proj=nad83:2001 +datum+nad83 +to +proj=latlong +datum=nad83
> 
> 
> I believe, but cannot be sure, that you need to use "+init=nad83:2001"
> and not "+proj=".  At least, if I use the normal cs2cs program that
> comes with proj4 that particular combination lets me enter data and
> does some kind of conversion.
> 
> Unfortunately, I've never used a shapefile in a state plane system, and don't 
> have a way of verifying that it's the right way to go.  But you might try
> 
>   shpcs2cs inshape outshape +init=nad83:2001 +to +proj=latlong +datum=WGS84
> 
> and see if it produces a shapefile that, for example, lines features
> up correctly with terraserver images or something.
> 
> I'd say you might be better off trying to use ogr2ogr for this
> purpose, but for the life of me I have no idea what WKT to use (don't
> see an obvious EPSG number for that transformation).  Gerry might know?
> 

-- 
Gerry Creager -- gerry.creager at tamu.edu
Network Engineering -- AATLT, Texas A&M University	
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