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Subject: Re: [boost] geodetic library
From: Barend Gehrels (barend_at_[hidden])
Date: 2009-08-28 04:38:13

Michael Fawcett wrote:
> On Thu, Aug 27, 2009 at 3:55 PM, DE<satan66613_at_[hidden]> wrote:
>> i implemented very accurate direct and inverse geodetic problem
>> routines (as well as geocentric (X, Y, Z) to geodetic (B, L, H) conversion)
>> i used bessel's method to derive the formulas
>> 6 iterations for both direct and inverse routines is enough to
>> converge to full double precision (16 digits)
>> however the formulas themselves provide 9 significant digits
>> that is 1cm accuracy regardless of range (i.e. range = 1m..20000km)
>> to get acceptable accuracy, say, 2 iterations is enough (or even 1)
Do you mean transformations or projections? Our library GGL (Generic
Geometry Library), aimed for Boost, has (about 100) projections
(converted from Proj4). But proj4 datum transformations are not yet
converted. So it might be useful to see if your transformations would
fit into our library. There were already questions about transformations.

By the way:
GGL has an own mailing list which can be found here:, a wiki and ticket system
which be found here: . Sources are at boost
(Preview 4): and the latest
version is still hosted at Geodan SVN (interested people can have
access; it will be also moved to Boost sandbox in ~ october).

>> however there are several other aspects uncovered (area and perimeter,
>> projections, etc.)
> Do you have plans to support WGS84? What about Vincenty?
> --Michael Fawcett

GGL has Vincenty distance calculations but you probably mean
transformations here?

Regards, Barend

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