[GRASS-user] Feet-to-Meter Conversion

[Markus Metz]

On Mon, Jun 18, 2012 at 5:46 PM, Rich Shepard <rshepard at appl-ecosys.com> wrote:
>  The standard conversion factor from feet to meters is 1 ft = 0.3048 m.
> However, the conversion factor for US Survey Feet (frequently the distance
> unit in the US State Plane Coordinate System) is 1 US ft = 0.3600 m.

Are you sure? I thought 1 US survey foot is exactly 1200/3937 m, appr.
0.3048006 m, or the other way around 1 meter = 3.280833333 U.S. Survey
Feet [0].

Markus M

[0] http://www.ngs.noaa.gov/faq.shtml#Feet

>
>  I don't know the magnitude of the error when GRASS assumes international
> feet (0.3408) as the conversion factor. When I have a project location in
> SPCS is there any harm in manually changing the PROJ_UNITS from 0.3048 to
> 0.3600?
>
> Rich
>
>
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