Details Ticket 3673


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Serial Number 3673
Subject location setup: sterea yields 'invalid projection'
Area grass6
Queue grass
Requestors tutey@o2.pl
Owner none
Status open
Last User Contact Wed Jul 26 16:48:41 2006 (2 yr ago)
Current Priority 30
Final Priority 70
Due No date assigned
Last Action Wed Jul 26 16:48:41 2006 (2 yr ago)
Created Fri Sep 23 15:38:26 2005 (3 yr ago)

Transaction History Ticket 3673


Fri, Sep 23 2005 15:38:26    Request created by guest  
Subject: location setup: sterea yields 

Platform: GNU/Linux/i386
grass obtained from: CVS
grass binary for platform: Compiled from Sources
GRASS Version: cvs 07.09.2005

Although Grass supports sterea projection via PROJ.4 library, sterea is recognized
as an "invalid projection" at the location setup stage in Grass 6.1 cvs.

Maciek
Fri, Sep 23 2005 16:49:39    Mail sent by paul-grass@stjohnspoint.co.uk  
Return-Path <paul-grass@stjohnspoint.co.uk>
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Date Fri, 23 Sep 2005 15:49:23 +0100 (BST)
From Paul Kelly <paul-grass@stjohnspoint.co.uk>
To Request Tracker <grass-bugs@intevation.de>
Cc grass5@grass.itc.it
Subject Re: [GRASS5] [bug #3673] (grass) location setup: sterea yields
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On Fri, 23 Sep 2005, Request Tracker wrote:

> Although Grass supports sterea projection via PROJ.4 library, sterea is recognized
as an "invalid projection" at the location setup stage in Grass 6.1 cvs.

That would be because it isn't in the list in lib/gis/projections.
Has it been recently added to PROJ (i.e. the last 5 years ;) ) That might 
explain why it's not there. But adding support for it to g.setproj would 
probably involve changes to lib/gis/geo_init.c and maybe other files as 
well.

If you know the parameters there is no problem to manually set it up by 
editing the PROJ_INFO or even put it in with g.proj using EPSG codes or 
WKT files etc. All the g.setproj and G_geo_* stuff is just a bit of a hack 
to make up for the absence in PROJ of a specification of the parameters 
associated with each projection. It doesn't attempt to be definitive for 
all the projections supported and never will.

I asked the author of PROJ about this once but on a point of principle he 
doesn't want to produce such a definitive specification and prefers that
people read the PROJ documentation and understand the parameters they are
using, rather than answer a series of questions like g.setproj attempts to do.
Paul


Sat, Sep 24 2005 13:00:16    Mail sent by msieczka  
Paul wrote:

> Has it been recently added to PROJ (i.e. the last 5 years ;) )

Yes, few months ago.

> If you know the parameters there is no problem to manually set it up by 
> editing the PROJ_INFO

That's the way I'm doing it. (And I don't mean this entry as a support
request. It is a bug report.)

> or even put it in with g.proj using EPSG codes or 
> WKT files etc.

FYI - GDAL doesn't have any EPSG codes for sterea.

> I asked the author of PROJ about this once but on a point of principle he 
> doesn't want to produce such a definitive specification and prefers that
> people read the PROJ documentation and understand the parameters they are
> using

Kind of right. Still it is a bug(gy) in Grass and should be fixed, that's what
a simple Grass user says, ugh.

> rather than answer a series of questions like g.setproj attempts to
> do.

So, in it's current form g.setproj is buggy as it doesn't behave the way it is
supposed to when sterea is involved. No matter how tiny this bug is. I'll
leave this report open if you don't mind so we are aware that a problem exists.
Maciek
Wed, Jul 26 2006 15:02:47    User changed to tutey@o2.pl by msieczka  
Wed, Jul 26 2006 15:20:53    Subject changed to location setup: sterea yields 'invalid projection' by msieczka  
Wed, Jul 26 2006 16:48:41    Mail sent by msieczka  
msieczka wrote (Sat, Sep 24 2005 13:00:16):

Paul wrote:

>> Has it been recently added to PROJ (i.e. the last 5 years ;) )

Maciek wrote:

> Yes, few months ago.
 
>> If you know the parameters there is no problem to manually set it up by 
>> editing the PROJ_INFO or even put it in with g.proj using EPSG codes or 
>> WKT files etc.

> FYI - GDAL doesn't have any EPSG codes for sterea.

Update: now sterea is used in GDAL (1.3.2) and PROJ (4.5 beta) for 14 European
stereographic grids (18 listed below, but 4 are duplicate "deprecated"):

$ grep -B1 '+proj=sterea' /usr/local/share/proj/epsg | awk '/^#/ {print} /^</
{print $1" "$2}'

# NAD83(CSRS98) / New Brunswick Stereo (deprecated)
<2036> +proj=sterea
# Pulkovo 1942(58) / Poland zone I (deprecated)
<2171> +proj=sterea
# Pulkovo 1942(58) / Poland zone II
<2172> +proj=sterea
# Pulkovo 1942(58) / Poland zone III
<2173> +proj=sterea
# Pulkovo 1942(58) / Poland zone IV
<2174> +proj=sterea
# ATS77 / New Brunswick Stereographic (ATS77)
<2200> +proj=sterea
# ATS77 / Prince Edward Isl. Stereographic (ATS77)
<2290> +proj=sterea
# NAD83(CSRS98) / Prince Edward Isl. Stereographic (NAD83) (deprecated)
<2291> +proj=sterea
# NAD83(CSRS98) / Prince Edward Isl. Stereographic (NAD83) (deprecated)
<2292> +proj=sterea
# NAD83(CSRS) / New Brunswick Stereo
<2953> +proj=sterea
# NAD83(CSRS) / Prince Edward Isl. Stereographic (NAD83)
<2954> +proj=sterea
# Pulkovo 1942(58) / Poland zone I
<3120> +proj=sterea
# Pulkovo 1942(58) / GUGiK-80
<3328> +proj=sterea
# Deir ez Zor / Levant Stereographic
<22780> +proj=sterea
# Amersfoort / RD Old
<28991> +proj=sterea
# Amersfoort / RD New
<28992> +proj=sterea
# Dealul Piscului 1933/ Stereo 33
<31600> +proj=sterea
# Dealul Piscului 1970/ Stereo 70
<31700> +proj=sterea



g.setproj should support sterea.

Maciek
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