[Proj] Re: Extracting the to_meter parameter from a projection

Frank Warmerdam warmerdam at pobox.com
Tue Nov 15 18:38:10 EST 2005

On 11/15/05, Hearne, Michael  (US SSA) <michael.hearne at baesystems.com> wrote:
> Frank - Thanks for your quick response.  I searched through my copy of
> the proj4 source and couldn't find a function called pj_get_units_ref().
> Is this defined in a relatively recent version of proj4?  My copy is
> perhaps a couple of years old.  I do have the pj_units table defined in
> "pj_units.c".


Yes, pj_get_units_ref() is relatively new.  It, and some similar functions,
were added to give access to internal tables needed for "smart" applications
that need to know more about coordinate system options.

> Also, we tested pj_get_def() for a fairly exhaustive list of
> projections, and none of them returned a "+unit=" string token (list at
> bottom of email.)  Does this mean that all of these projections are in
> units of meters?

All projections methods have an implicit unit type of meters unless
otherwise set.  Try a definition like Arizona East NAD27 (+init=epsg:26748).

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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