Info on proj4 formulas

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Info on proj4 formulas

Andrea Peri
Hi,

I'm just now subscribe to this MialingLIst so before all
My best wish to all the readers.
:)

I'm searching info about what formula is use in the proj4 to reproiect data.
There is a document where is describe the used formulas. ?

I need to understand how far is the proj4 results from other tools used in Italy

AFAIK in Italy is used a formula usually know as the "Formula's Bonifacino".

Thx,

--
-----------------
Andrea Peri
. . . . . . . . .
qwerty àèìòù
-----------------

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Re: Info on proj4 formulas

jmckenna
Administrator
Hi Andrea,

Have you reviewed the "Documentation" section of
http://trac.osgeo.org/proj/ ?

-jeff


--
Jeff McKenna
MapServer Consulting and Training Services
http://www.gatewaygeomatics.com/



On 2014-05-08, 2:27 PM, Andrea Peri wrote:

> Hi,
>
> I'm just now subscribe to this MialingLIst so before all
> My best wish to all the readers.
> :)
>
> I'm searching info about what formula is use in the proj4 to reproiect data.
> There is a document where is describe the used formulas. ?
>
> I need to understand how far is the proj4 results from other tools used
> in Italy
>
> AFAIK in Italy is used a formula usually know as the "Formula's Bonifacino".
>
> Thx,
>
> --
> -----------------
> Andrea Peri
> . . . . . . . . .
> qwerty àèìòù
> -----------------
>
>


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Re: Info on proj4 formulas

Andrea Peri
Hi Jeff,

I just this morning search in the 
OF90-284.pdf
but nothing found about the formulas.

I search better in other sections of documentation.

A.



2014-05-08 19:38 GMT+02:00 Jeff McKenna <[hidden email]>:
Hi Andrea,

Have you reviewed the "Documentation" section of
http://trac.osgeo.org/proj/ ?

-jeff


--
Jeff McKenna
MapServer Consulting and Training Services
http://www.gatewaygeomatics.com/



On 2014-05-08, 2:27 PM, Andrea Peri wrote:
> Hi,
>
> I'm just now subscribe to this MialingLIst so before all
> My best wish to all the readers.
> :)
>
> I'm searching info about what formula is use in the proj4 to reproiect data.
> There is a document where is describe the used formulas. ?
>
> I need to understand how far is the proj4 results from other tools used
> in Italy
>
> AFAIK in Italy is used a formula usually know as the "Formula's Bonifacino".
>
> Thx,
>
> --
> -----------------
> Andrea Peri
> . . . . . . . . .
> qwerty àèìòù
> -----------------
>
>


_______________________________________________
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--
-----------------
Andrea Peri
. . . . . . . . .
qwerty àèìòù
-----------------

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Re: Info on proj4 formulas

Andre Joost
In reply to this post by Andrea Peri
Am 08.05.2014 19:27, schrieb Andrea Peri:

>
> I'm searching info about what formula is use in the proj4 to reproiect data.
> There is a document where is describe the used formulas. ?
>

Look out for John P. Snyder, "Map Projections - A Working Manual". It is
almost the bible for projection calculations.

HTH,
André Joost

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Re: Info on proj4 formulas

support.mn
In reply to this post by Andrea Peri
Hello,

the exact formulas are in the source code..
the source code is the definition and
formula..

Regards: Janne.

---------------------------------------------------------


Andrea Peri [[hidden email]] kirjoitti:

> Hi Jeff,
>
> I just this morning search in the
> OF90-284.pdf
> but nothing found about the formulas.
>
> I search better in other sections of documentation.
>
> A.
>
>
>
> 2014-05-08 19:38 GMT+02:00 Jeff McKenna <[hidden email]>:
>
> > Hi Andrea,
> >
> > Have you reviewed the "Documentation" section of
> > http://trac.osgeo.org/proj/ ?
> >
> > -jeff
> >
> >
> > --
> > Jeff McKenna
> > MapServer Consulting and Training Services
> > http://www.gatewaygeomatics.com/
> >
> >
> >
> > On 2014-05-08, 2:27 PM, Andrea Peri wrote:
> > > Hi,
> > >
> > > I'm just now subscribe to this MialingLIst so before all
> > > My best wish to all the readers.
> > > :)
> > >
> > > I'm searching info about what formula is use in the proj4 to reproiect
> > data.
> > > There is a document where is describe the used formulas. ?
> > >
> > > I need to understand how far is the proj4 results from other tools used
> > > in Italy
> > >
> > > AFAIK in Italy is used a formula usually know as the "Formula's
> > Bonifacino".
> > >
> > > Thx,
> > >
> > > --
> > > -----------------
> > > Andrea Peri
> > > . . . . . . . . .
> > > qwerty àèìòù
> > > -----------------
> > >
> > >
> >
> >
> > _______________________________________________
> > Proj mailing list
> > [hidden email]
> > http://lists.maptools.org/mailman/listinfo/proj
> >
>
>
>
> --
> -----------------
> Andrea Peri
> . . . . . . . . .
> qwerty àèìòù
> -----------------
>
> _______________________________________________
> Proj mailing list
> [hidden email]
> http://lists.maptools.org/mailman/listinfo/proj


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Re: Info on proj4 formulas

Andrea Peri

Hi,
You have right.
I can read and try to understand the code but i don't know the PROJ lib.  There is a specific file source dedicate to the reprojection functions ?

Thx,
Andrea


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Re: Info on proj4 formulas

Norman Vine

On May 9, 2014, at 10:05 AM, Andrea Peri <[hidden email]> wrote:

Hi,
You have right.
I can read and try to understand the code but i don't know the PROJ lib.  There is a specific file source dedicate to the reprojection functions ?



Each projection has its own file these are named  "PJ_XXXX"
where XXXX is an abbreviation of the projection's name

Proj4 is the codification of Snyder's "Map Projections: A Working Manual"
Where the derivation of the projections are discussed
this is available as a pdf from
http://pubs.er.usgs.gov/publication/pp1395


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Re: Info on proj4 formulas

Nikolaos Ves
Intresting,

But now I'm wondering if the OGP's "Geomatics Guidance Note Number 7,
part 2 Coordinate Conversions and Transformations including Formulas"
[0] has been taken into account in the realizations of the formulas.

[0] http://www.ogp.org.uk/pubs/373-07-2.pdf

On Fri, May 9, 2014 at 5:19 PM, Norman Vine <[hidden email]> wrote:

>
> On May 9, 2014, at 10:05 AM, Andrea Peri <[hidden email]> wrote:
>
> Hi,
> You have right.
> I can read and try to understand the code but i don't know the PROJ lib.
> There is a specific file source dedicate to the reprojection functions ?
>
>
>
> Each projection has its own file these are named  "PJ_XXXX"
> where XXXX is an abbreviation of the projection's name
>
> Proj4 is the codification of Snyder's "Map Projections: A Working Manual"
> Where the derivation of the projections are discussed
> this is available as a pdf from
> http://pubs.er.usgs.gov/publication/pp1395
>
>
> _______________________________________________
> Proj mailing list
> [hidden email]
> http://lists.maptools.org/mailman/listinfo/proj
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Re: Info on proj4 formulas

Finn, Michael
Thanks for posting this!



On Fri, May 9, 2014 at 8:31 AM, Nick Ves <[hidden email]> wrote:
Intresting,

But now I'm wondering if the OGP's "Geomatics Guidance Note Number 7,
part 2 Coordinate Conversions and Transformations including Formulas"
[0] has been taken into account in the realizations of the formulas.

[0] http://www.ogp.org.uk/pubs/373-07-2.pdf

On Fri, May 9, 2014 at 5:19 PM, Norman Vine <[hidden email]> wrote:
>
> On May 9, 2014, at 10:05 AM, Andrea Peri <[hidden email]> wrote:
>
> Hi,
> You have right.
> I can read and try to understand the code but i don't know the PROJ lib.
> There is a specific file source dedicate to the reprojection functions ?
>
>
>
> Each projection has its own file these are named  "PJ_XXXX"
> where XXXX is an abbreviation of the projection's name
>
> Proj4 is the codification of Snyder's "Map Projections: A Working Manual"
> Where the derivation of the projections are discussed
> this is available as a pdf from
> http://pubs.er.usgs.gov/publication/pp1395
>
>
> _______________________________________________
> Proj mailing list
> [hidden email]
> http://lists.maptools.org/mailman/listinfo/proj
_______________________________________________
Proj mailing list
[hidden email]
http://lists.maptools.org/mailman/listinfo/proj


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Re: Info on proj4 formulas

Antti Castrén-2
In reply to this post by Nikolaos Ves
Hi,

It seems that they differ at least on Transverse Mercator. OGP
Guidance currently recommends so called JHS formulas which are
satisfactory within +/-40 degrees from central meridian compared to
Snyder's +/-4 degrees. Snyder's formulas seem to be coded in proj.4
PJ_tmerc if I have read the current version correctly.

For more information read OGP document pages 48...53


Cheers,

  Antti

FYI: The so called JHS formulas were actually created by prof R A
Hirvonen and published (in Finnish) already back in 1972.
http://en.wikipedia.org/wiki/Reino_Antero_Hirvonen


2014-05-09 17:31 GMT+03:00 Nick Ves <[hidden email]>:

> Intresting,
>
> But now I'm wondering if the OGP's "Geomatics Guidance Note Number 7,
> part 2 Coordinate Conversions and Transformations including Formulas"
> [0] has been taken into account in the realizations of the formulas.
>
> [0] http://www.ogp.org.uk/pubs/373-07-2.pdf
>
> On Fri, May 9, 2014 at 5:19 PM, Norman Vine <[hidden email]> wrote:
>>
>> On May 9, 2014, at 10:05 AM, Andrea Peri <[hidden email]> wrote:
>>
>> Hi,
>> You have right.
>> I can read and try to understand the code but i don't know the PROJ lib.
>> There is a specific file source dedicate to the reprojection functions ?
>>
>>
>>
>> Each projection has its own file these are named  "PJ_XXXX"
>> where XXXX is an abbreviation of the projection's name
>>
>> Proj4 is the codification of Snyder's "Map Projections: A Working Manual"
>> Where the derivation of the projections are discussed
>> this is available as a pdf from
>> http://pubs.er.usgs.gov/publication/pp1395
>>
>>
>> _______________________________________________
>> Proj mailing list
>> [hidden email]
>> http://lists.maptools.org/mailman/listinfo/proj
> _______________________________________________
> Proj mailing list
> [hidden email]
> http://lists.maptools.org/mailman/listinfo/proj
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Re: Info on proj4 formulas

Charles Karney
The JHS formulas (extended to 6th order) are proj.4's etmerc projection
(e = "extended").  The 4th-order series in JHS were first given by
Krueger in 1912.  The same formulas (at 6th order) are now recommended
by NGA for UTM (see my posting of 2014-04-29).

   --Charles

On 2014-05-09 13:36, Antti Castrén wrote:

> Hi,
>
> It seems that they differ at least on Transverse Mercator. OGP
> Guidance currently recommends so called JHS formulas which are
> satisfactory within +/-40 degrees from central meridian compared to
> Snyder's +/-4 degrees. Snyder's formulas seem to be coded in proj.4
> PJ_tmerc if I have read the current version correctly.
>
> For more information read OGP document pages 48...53
>
>
> Cheers,
>
>    Antti
>
> FYI: The so called JHS formulas were actually created by prof R A
> Hirvonen and published (in Finnish) already back in 1972.
> http://en.wikipedia.org/wiki/Reino_Antero_Hirvonen
>
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Re: Info on proj4 formulas

peifer
In reply to this post by Nikolaos Ves
On 2014-05-09 16:31, Nick Ves wrote:
> Intresting,
>
> But now I'm wondering if the OGP's "Geomatics Guidance Note Number 7,
> part 2 Coordinate Conversions and Transformations including Formulas"
> [0] has been taken into account in the realizations of the formulas.
>
> [0] http://www.ogp.org.uk/pubs/373-07-2.pdf
>

At least Thomas Flemming mentions an earlier version of the guidance
note, see http://trac.osgeo.org/proj/browser/trunk/proj/src/PJ_krovak.c

Hermann



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Re: Info on proj4 formulas

Clifford J Mugnier
Variations in projection formulae can be an academic exercise or a catastrophe, depending on the application.  Most GIS applications can use practically any truncation of the infinite series (4th order, 5th order, 6th order, etc.) with little to no effect to day-to-day work.  There are two exceptions:

1.) Military.  Always use whatever is currently promulgated by NGA for NATO/SEATO applications.  This helps avoid “friendly fire” incidents among units that provide indirect fire support.
 
2.) Oil and Gas.  Exploration and Production concessions leased by national governments use map projections for Grid Systems as legal coordinate systems sometimes based on specific truncations.  When that is in effect, the use of other truncations (especially in offshore areas) can produce catastrophic errors in positioning.  

Sometimes, mathematical distortions at various distances from the projection origin are on purpose!

Cliff Mugnier
LOUISIANA STATE UNIVERSITY
________________________________________
From: [hidden email] <[hidden email]> on behalf of Hermann Peifer <[hidden email]>
Sent: Friday, May 9, 2014 12:47 PM
To: PROJ.4 and general Projections Discussions
Subject: Re: [Proj] Info on proj4 formulas

On 2014-05-09 16:31, Nick Ves wrote:
> Intresting,
>
> But now I'm wondering if the OGP's "Geomatics Guidance Note Number 7,
> part 2 Coordinate Conversions and Transformations including Formulas"
> [0] has been taken into account in the realizations of the formulas.
>
> [0] http://www.ogp.org.uk/pubs/373-07-2.pdf
>

At least Thomas Flemming mentions an earlier version of the guidance
note, see http://trac.osgeo.org/proj/browser/trunk/proj/src/PJ_krovak.c

Hermann



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Re: Info on proj4 formulas

Mikhail
Well, it seems to me first part of your letter contradicts (1) and (2).

Anyway, if there is negligible difference (say in order of cm) than what
could come wrong friendly fire or drilling?

But I have to admit that consequences could be severe for surveyor in
two cases:

1. there is a legal requirement to use specific formulas.  In this case
we are in trouble
even the formulas yield exactly the same results but not recommended
ones were used.

2. If required formulas were distorted on purpose.   Then this is just a
case of classified information.


Best Regards,
Mikhail

On 5/9/2014 10:59 AM, Clifford J Mugnier wrote:

> Variations in projection formulae can be an academic exercise or a catastrophe, depending on the application.  Most GIS applications can use practically any truncation of the infinite series (4th order, 5th order, 6th order, etc.) with little to no effect to day-to-day work.  There are two exceptions:
>
> 1.) Military.  Always use whatever is currently promulgated by NGA for NATO/SEATO applications.  This helps avoid “friendly fire” incidents among units that provide indirect fire support.
>    
> 2.) Oil and Gas.  Exploration and Production concessions leased by national governments use map projections for Grid Systems as legal coordinate systems sometimes based on specific truncations.  When that is in effect, the use of other truncations (especially in offshore areas) can produce catastrophic errors in positioning.
>
> Sometimes, mathematical distortions at various distances from the projection origin are on purpose!
>
> Cliff Mugnier
> LOUISIANA STATE UNIVERSITY
> ________________________________________
> From: [hidden email] <[hidden email]> on behalf of Hermann Peifer <[hidden email]>
> Sent: Friday, May 9, 2014 12:47 PM
> To: PROJ.4 and general Projections Discussions
> Subject: Re: [Proj] Info on proj4 formulas
>
> On 2014-05-09 16:31, Nick Ves wrote:
>> Intresting,
>>
>> But now I'm wondering if the OGP's "Geomatics Guidance Note Number 7,
>> part 2 Coordinate Conversions and Transformations including Formulas"
>> [0] has been taken into account in the realizations of the formulas.
>>
>> [0] http://www.ogp.org.uk/pubs/373-07-2.pdf
>>
> At least Thomas Flemming mentions an earlier version of the guidance
> note, see http://trac.osgeo.org/proj/browser/trunk/proj/src/PJ_krovak.c
>
> Hermann
>
>
>
> _______________________________________________
> Proj mailing list
> [hidden email]
> http://lists.maptools.org/mailman/listinfo/proj
> _______________________________________________
> Proj mailing list
> [hidden email]
> http://lists.maptools.org/mailman/listinfo/proj




PLEASE NOTE: This message, including any attachments, may include privileged,
confidential and/or inside information. Any dissemination, distribution or copy
of this communication by   anyone other than the intended recipient is strictly
prohibited. If you are not the intended recipient, please notify the sender by
replying to this message and then delete it from your system. Information
provided via electronic media is not guaranteed against defects including
translation and transmission errors. The company accepts no liability for any
damage caused by any virus transmitted by this email.

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Re: Info on proj4 formulas

Clifford J Mugnier

In Southern Algeria, it's tens of meters.  

Truncations were common in the 19th century, and were used to minimize the computational load to develop projection tables.  As welding technology advanced and stiff-leg platforms got further out offshore, the old projection tables produced highly distorted non-conformal errors.  Since the projection and the tables were legislated, that was the basis for the concession block coordinates.  Some areas like North Africa have experienced the same problems on land rather than offshore.

This affects warfighters and surveyors.  Not often, but it happens and not just in North Africa.  OGP uses the French Army Truncated Cubic Lambert specifically for this application.  Similar variations occur with the transverse Mercator.

Cliff Mugnier
LOUISIANA STATE UNIVERSITY
________________________________________
From: [hidden email] <[hidden email]> on behalf of Mikhail Tchernychev <[hidden email]>
Sent: Friday, May 9, 2014 1:28 PM
To: PROJ.4 and general Projections Discussions
Subject: Re: [Proj] Info on proj4 formulas

Well, it seems to me first part of your letter contradicts (1) and (2).

Anyway, if there is negligible difference (say in order of cm) than what
could come wrong friendly fire or drilling?

But I have to admit that consequences could be severe for surveyor in
two cases:

1. there is a legal requirement to use specific formulas.  In this case
we are in trouble
even the formulas yield exactly the same results but not recommended
ones were used.

2. If required formulas were distorted on purpose.   Then this is just a
case of classified information.


Best Regards,
Mikhail

On 5/9/2014 10:59 AM, Clifford J Mugnier wrote:

> Variations in projection formulae can be an academic exercise or a catastrophe, depending on the application.  Most GIS applications can use practically any truncation of the infinite series (4th order, 5th order, 6th order, etc.) with little to no effect to day-to-day work.  There are two exceptions:
>
> 1.)   Military.  Always use whatever is currently promulgated by NGA for NATO/SEATO applications.  This helps avoid “friendly fire” incidents among units that provide indirect fire support.
>
> 2.)   Oil and Gas.  Exploration and Production concessions leased by national governments use map projections for Grid Systems as legal coordinate systems sometimes based on specific truncations.  When that is in effect, the use of other truncations (especially in offshore areas) can produce catastrophic errors in positioning.
>
> Sometimes, mathematical distortions at various distances from the projection origin are on purpose!
>
> Cliff Mugnier
> LOUISIANA STATE UNIVERSITY
> ________________________________________
> From: [hidden email] <[hidden email]> on behalf of Hermann Peifer <[hidden email]>
> Sent: Friday, May 9, 2014 12:47 PM
> To: PROJ.4 and general Projections Discussions
> Subject: Re: [Proj] Info on proj4 formulas
>
> On 2014-05-09 16:31, Nick Ves wrote:
>> Intresting,
>>
>> But now I'm wondering if the OGP's "Geomatics Guidance Note Number 7,
>> part 2 Coordinate Conversions and Transformations including Formulas"
>> [0] has been taken into account in the realizations of the formulas.
>>
>> [0] http://www.ogp.org.uk/pubs/373-07-2.pdf
>>
> At least Thomas Flemming mentions an earlier version of the guidance
> note, see http://trac.osgeo.org/proj/browser/trunk/proj/src/PJ_krovak.c
>
> Hermann
>
>
>
> _______________________________________________
> Proj mailing list
> [hidden email]
> http://lists.maptools.org/mailman/listinfo/proj
> _______________________________________________
> Proj mailing list
> [hidden email]
> http://lists.maptools.org/mailman/listinfo/proj




PLEASE NOTE: This message, including any attachments, may include privileged,
confidential and/or inside information. Any dissemination, distribution or copy
of this communication by   anyone other than the intended recipient is strictly
prohibited. If you are not the intended recipient, please notify the sender by
replying to this message and then delete it from your system. Information
provided via electronic media is not guaranteed against defects including
translation and transmission errors. The company accepts no liability for any
damage caused by any virus transmitted by this email.

Geometrics Inc. | 2190 Fortune Drive | San Jose, CA 95131 USA
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Re: Info on proj4 formulas

Mikhail
Thank you for interesting information! I did not come to me that
projection tables are still in use,
and new methods should match old ones :)

Best Regards
Mikhail

On 5/9/2014 12:14 PM, Clifford J Mugnier wrote:

> In Southern Algeria, it's tens of meters.
>
> Truncations were common in the 19th century, and were used to minimize the computational load to develop projection tables.  As welding technology advanced and stiff-leg platforms got further out offshore, the old projection tables produced highly distorted non-conformal errors.  Since the projection and the tables were legislated, that was the basis for the concession block coordinates.  Some areas like North Africa have experienced the same problems on land rather than offshore.
>
> This affects warfighters and surveyors.  Not often, but it happens and not just in North Africa.  OGP uses the French Army Truncated Cubic Lambert specifically for this application.  Similar variations occur with the transverse Mercator.
>
> Cliff Mugnier
> LOUISIANA STATE UNIVERSITY
> ________________________________________
> From: [hidden email] <[hidden email]> on behalf of Mikhail Tchernychev <[hidden email]>
> Sent: Friday, May 9, 2014 1:28 PM
> To: PROJ.4 and general Projections Discussions
> Subject: Re: [Proj] Info on proj4 formulas
>
> Well, it seems to me first part of your letter contradicts (1) and (2).
>
> Anyway, if there is negligible difference (say in order of cm) than what
> could come wrong friendly fire or drilling?
>
> But I have to admit that consequences could be severe for surveyor in
> two cases:
>
> 1. there is a legal requirement to use specific formulas.  In this case
> we are in trouble
> even the formulas yield exactly the same results but not recommended
> ones were used.
>
> 2. If required formulas were distorted on purpose.   Then this is just a
> case of classified information.
>
>
> Best Regards,
> Mikhail
>
> On 5/9/2014 10:59 AM, Clifford J Mugnier wrote:
>> Variations in projection formulae can be an academic exercise or a catastrophe, depending on the application.  Most GIS applications can use practically any truncation of the infinite series (4th order, 5th order, 6th order, etc.) with little to no effect to day-to-day work.  There are two exceptions:
>>
>> 1.)   Military.  Always use whatever is currently promulgated by NGA for NATO/SEATO applications.  This helps avoid “friendly fire” incidents among units that provide indirect fire support.
>>
>> 2.)   Oil and Gas.  Exploration and Production concessions leased by national governments use map projections for Grid Systems as legal coordinate systems sometimes based on specific truncations.  When that is in effect, the use of other truncations (especially in offshore areas) can produce catastrophic errors in positioning.
>>
>> Sometimes, mathematical distortions at various distances from the projection origin are on purpose!
>>
>> Cliff Mugnier
>> LOUISIANA STATE UNIVERSITY
>> ________________________________________
>> From: [hidden email] <[hidden email]> on behalf of Hermann Peifer <[hidden email]>
>> Sent: Friday, May 9, 2014 12:47 PM
>> To: PROJ.4 and general Projections Discussions
>> Subject: Re: [Proj] Info on proj4 formulas
>>
>> On 2014-05-09 16:31, Nick Ves wrote:
>>> Intresting,
>>>
>>> But now I'm wondering if the OGP's "Geomatics Guidance Note Number 7,
>>> part 2 Coordinate Conversions and Transformations including Formulas"
>>> [0] has been taken into account in the realizations of the formulas.
>>>
>>> [0] http://www.ogp.org.uk/pubs/373-07-2.pdf
>>>
>> At least Thomas Flemming mentions an earlier version of the guidance
>> note, see http://trac.osgeo.org/proj/browser/trunk/proj/src/PJ_krovak.c
>>
>> Hermann
>>
>>
>>
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