Costa Rica Norte in nad/world definition...

[Carl Godkin-2]

Hi,

The PROJ.4 file nad/world contains a definition for the "Costa Rica Norte" coordinate

system (costa-n) that may have a typo.

The false northing is listed in this file (in current SVN) with 

   y_0=217820.522 

but I believe that it's really supposed to be y_0=271820.522 instead.

We received some data for this coordinate system from a customer and it uses

this definition.  With the "corrected" numbers, the customer's locations in

geographic and projected coordinates match when converted using "proj."

However, I can't find another source for it on the web anywhere to confirm.

Does someone have a way to check this out?

Thanks,

carl

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[Clifford J Mugnier]

Some javascript/style in this post has been disabled (why?)

April 2008 issue of my Grids and Datums column is on Costa Rica.  It can be downloaded from:

 

www.ASPRS.org/resources/grids

 

C. Mugnier

LOUISIANA STATE UNIVERSITY

---

From: [hidden email] on behalf of Carl Godkin
Sent: Fri 10-Jul-09 13:07
To: [hidden email]
Subject: [Proj] Costa Rica Norte in nad/world definition...

Hi,

The PROJ.4 file nad/world contains a definition for the "Costa Rica Norte" coordinate

system (costa-n) that may have a typo.

The false northing is listed in this file (in current SVN) with 

   y_0=217820.522 

but I believe that it's really supposed to be y_0=271820.522 instead.

We received some data for this coordinate system from a customer and it uses

this definition.  With the "corrected" numbers, the customer's locations in

geographic and projected coordinates match when converted using "proj."

However, I can't find another source for it on the web anywhere to confirm.

Does someone have a way to check this out?

Thanks,

carl

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[Carl Godkin-2]

On Fri, Jul 10, 2009 at 12:26 PM, Clifford J Mugnier <[hidden email]> wrote:

April 2008 issue of my Grids and Datums column is on Costa Rica.  It can be downloaded from:

 

www.ASPRS.org/resources/grids

 

Dr. Mugnier's paper uses  False Easting = 271,820.522 as well, so I believe

this is a bug in the PROJ.4 nad/world file. 

Thanks,

carl

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[Hermann Peifer]

Carl Godkin wrote:

> On Fri, Jul 10, 2009 at 12:26 PM, Clifford J Mugnier <[hidden email]> wrote:
>
>>  April 2008 issue of my *Grids and Datums* column is on *Costa Rica*.  It
>> can be downloaded from:
>>
>> www.ASPRS.org/resources/grids
>>
>>
>
>
> Dr. Mugnier's paper uses  False Easting = 271,820.522 as well, so I believe
> this is a bug in the PROJ.4 nad/world file.
>
> Thanks,
>

BTW: most results from a random Internet search on 'costa rica norte 271820.522' indicate that this is the False Northing, rather than the False Easting value.

The country's Instituto Geográfico Nacional also mentions 271820.522 as the FN value, see page 3 at http://www.mopt.go.cr/ign/documentos/Lambert.pdf

Hermann
 

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[Carl Godkin-2]

On Sat, Jul 11, 2009 at 3:28 AM, Hermann Peifer <[hidden email]> wrote:

Carl Godkin wrote:
> On Fri, Jul 10, 2009 at 12:26 PM, Clifford J Mugnier <[hidden email]> wrote:
>
>>  April 2008 issue of my *Grids and Datums* column is on *Costa Rica*.  It
>> can be downloaded from:
>>
>> www.ASPRS.org/resources/grids
>>
>>
>
>
> Dr. Mugnier's paper uses  False Easting = 271,820.522 as well, so I believe
> this is a bug in the PROJ.4 nad/world file.
>
> Thanks,
>

BTW: most results from a random Internet search on 'costa rica norte 271820.522' indicate that this is the False Northing, rather than the False Easting value.

The country's Instituto Geográfico Nacional also mentions 271820.522 as the FN value, see page 3 at http://www.mopt.go.cr/ign/documentos/Lambert.pdf

Yes, you're right.  I just copied a typo out of Dr Mugnier's paper without thinking about

it.  This value is apparently very slippery.  Our customer had this as FN also.

Thanks for pointing that out,

carl 

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