[OSRS-PROJ] Re: Older Stateplane Definitions

[Paul Ramsey]

Frank Warmerdam wrote:

> Note that what you found by trial and error is EPSG 32148 - Washington North
> NAD83!  I think the first problem is just that the data is in the NAD83
> stateplane zone coordinates, not the NAD27 coordinates.

I just realized that. They used the new definition, but with feet as the
units instead of metres. Fun.
 
> Second, the +x_0 and +y_0 false eastings and northings are always in meters
> regardless of the +to_meter or +units settings.  I verified this as follows:

This I did not know. I assumed my problem was due to misdefinitions in
the epsg file. Apparently the problem is more likely to be that people
are using the new NAD83 definitions frequently with feet as the units,
whereas the new definitions are in metres.
 
> In short, I think the definitions of the NAD27 state plane zones are correct in the epsg
> file.

OK, I'll accept that explanation :)
 
>  > BTW, I have also extended the epsg file to include the "bonus" IDs which ESRI defines.
>  > I generally just replace the default epsg file with my extended version when I do a
>  > new proj4 install, but perhaps the "enhanced" file could be included as part of the
>  > proj4 distro?
> 
> I would likely prefer to offer them as an "esri" lookup file along side the epsg file
> rather than include the "bonus" ones right in the epsg file since they don't really
> have anything to do with epsg.

The esri lookup file would have to include all the epsg definitions
which esri has duplicated. If that's OK, I'll submit an esri file for
inclusion based on their projected coordinate systems list.

Paul
 
> I really need to update this stuff some time soon!
> 
> Best regards,
> 
> --
> ---------------------------------------+--------------------------------------
> I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush    | Geospatial Programmer for Rent
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     | Refractions Research
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