[Gvsig_english] Problems with EPSG.21781

Benjamin Ducke benjamin.ducke at oxfordarch.co.uk
Wed Nov 4 12:12:30 CET 2009


The error message comes directly from the PROJ4 library which
gvSIG uses to reproject from one SRS into another.
Unfortunately, PROJ4 documentation is quite horrible and fragmentary,
so I could not get down to the root of this issues.
There are, however some notes on the Swiss Mercator projection:

ftp://ftp.remotesensing.org/proj/swiss.pdf

It seems that +init=world:CH1903 is needed to initialize PROJ4
with that projection? Perhaps there is something that was overlooked
when rewriting the SRS engine for 1.9? I think this needs fixing
by the developers.

In the meantime, you could use the new tools in gvSIG 1.9 to define
a custom SRS. Just use the same parameters as EPSG 21781, expect
that you need to set azimuth to something very close to 90.0
(like 89.9999, as suggested in the link you mentioned).

Ben

----- Original Message -----
From: "FANGER Lorenz" <L.Fanger at csd.ch>
To: "gvsig internacional" <gvsig_internacional at listserv.gva.es>
Sent: Wednesday, November 4, 2009 11:31:22 AM GMT +01:00 Amsterdam / Berlin / Bern / Rome / Stockholm / Vienna
Subject: [Gvsig_english] Problems with EPSG.21781

Hello List

I visited a course about gvSIG in Munich and was quite impressed how far the development of gvSIG has evolved. With 1.9 it wll be defenetly intersting for our company to use gvSIG insted of a closed source Desktop-GIS.

How ever courrently the mayor problem with 1.9 (Build 1250) for us as a company based in switzerland is that the support of the swiss CRS is not given.

Defining the CRS of a view with EPSG:21781 fails and returns the Error "java.lang.Exception: In proj4 Projection Oblique Mercator not admit azimut close to 90". Also loading data with defined CRS of EPSG:21781 into a view with CRS EPSG:4326 returns a "User error"

If I remember well the 1.1 Versions once also had problems with swiss CRS. There the problem seems to be solved as the current stable versions do support swiss CRS

Does anybody knows a feasable work arround for common user? Is it planed to solve that bug? How can we supoort a solution of that problem (without experiences in programming and projections)?

I found a similar Mail in the List [1] from early this year but could not follow the mentioned "ugly hack".

[1] http://n2.nabble.com/libJCRS-Error-while-choosing-EPSG-21781-CRS-CH1903-LV03-td2186767.html#a2186767

Freundliche Grüsse
Lorenz Fanger
 
---------------------------------------------------------
Lorenz Fanger
Dipl. Natw. ETH & MSc (GIS)
 
CSD Ingenieure und Geologen AG
Rathaus, Postfach 34
7430 Thusis
Tel. +41 (0)81 632 15 00
Fax +41 (0)81 632 15 01
e-mail: l.fanger at csd.ch   www.csd.ch
 
 
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