[GRASSLIST:7266] Re: m.cogo link broken

David Finlayson david.p.finlayson at gmail.com
Tue Jun 21 17:11:23 EDT 2005

A good map projection can limit the damage. In the US, State Plane
projections are designed for accurate surveying work for fairly large
parts of a state (that is 100+ km). If I recall correctly the
Washington State Plane North projection (my home state) has a maximum
error of only a few cm over its target domain.


On 6/21/05, Paulo Marcondes <paulomarcondes at gmail.com> wrote:
> 2005/6/21, Hamish <hamish_nospam at yahoo.com>:
> > Angle to point away loses
> > meaning after the distance grows big enough that the shape of the Earth
> > matters.. but I guess this isn't what the module is for?
> If I recall correctly from my surveying classes, the maximum distance
> one could consider a flat earth is around 12 or 16 km. I mean, the
> surveying validity (sp??) is a square with 12 (or 16) km sides.
> Maybe a warning could be added to m/v.cogo regarding these issues.
> --
> Paulo Marcondes
> zpaulomarcondesz at gmail period comz
> my email has no z

David Finlayson
Marine Geology & Geophysics
School of Oceanography
Box 357940
University of Washington
Seattle, WA  98195-7940

Office: Marine Sciences Building, Room 112
Phone: (206) 616-9407
Web: http://students.washington.edu/dfinlays

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