[vtk-developers] Geocoordinate System Filter, 2D Text Manager, 2D Text Preformance, and Buffered Hardware Picking

Philip Schuchardt ohc at vt.edu
Sat Dec 22 11:32:15 EST 2007

Sweet.  This is exactly what I was looking for.  I'm going to have to  
play around with it.

On Dec 20, 2007, at 5:50 AM, Thompson, David C wrote:

> I had a quick glance at vtkGeography and it looks like it just uses  
> PROJ.4 under the hood. I don't know of any Swiss datums for PROJ.4  
> but I'll keep my eyes open. I'll also see if I can't find a home for  
> the OSGB36->WGS84 code as I'm a pack rat with code... I just *know*  
> I'll find a use for it sooner or later. :-)
> David
> ________________________________________
> From: vtk-developers-bounces+dcthomp=sandia.gov at vtk.org [vtk-developers-bounces+dcthomp=sandia.gov at vtk.org 
> ] On Behalf Of John Biddiscombe [biddisco at cscs.ch]
> Sent: Thursday, December 20, 2007 02:09
> To: Thompson, David C
> Cc: vtkdev; a.maclean at cas.edu.au
> Subject: Re: [vtk-developers] Geocoordinate System Filter, 2D Text  
> Manager, 2D Text Preformance, and Buffered Hardware Picking
> I was (naively?) hoping to hide all the different coordinate systems  
> in
> a utility library like PROJ.4 instead of implementing each one  
> (there are
> *tons* of them) as its own distinct subclass of vtkCoordinateSystem  
> the
> Absolutely. I made the class that I referred to because we needed to  
> drive around in a van with a GPS receiver and display the map data  
> around us, including the 3D buildings etc for measurements - where  
> all was specified in OSGB coords. The UK transformation is annoying  
> because the 1997 version includes special 'lookuptables' which  
> correct for errors which were made in the 1936 'official' mapping  
> where grids were not completely regular. This kind of 'exception' to  
> the standard projection/ellipsoid/nonsense makes it hard to create a  
> very general purpose any to any coordinate transformation.
> My experience with proj.4 is limited I remember reviewing it in the  
> late 1990s when I was working in that field - I suspect it can do  
> most stuff that the majority of users need. If you poke around with  
> any of these vtkGeography classes etc and there is a swiss grid  
> transformation implemented, please let me know. We have terrain data  
> and climate stuff that would look good blended.
> cheers
> JB
> way vtkGeography appears to. My (to date cursory) review of PROJ.4
> made me think that many of these datums can be compiled into the  
> library
> but perhaps it doesn't choose the most numerically stable way to  
> transform
> coordinates from one system to another?
>  David
> --
> John Biddiscombe,                            email:biddisco @ cscs.ch
> http://www.cscs.ch/about/BJohn.php
> CSCS, Swiss National Supercomputing Centre  | Tel:  +41 (91) 610.82.07
> Via Cantonale, 6928 Manno, Switzerland      | Fax:  +41 (91) 610.82.82
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