[GRASSLIST:3309] Re: [GRASS5] Re: National British Grid

[Markus Neteler]

Hi again,

I have update the CVS to also query for false northing in
transverse mercator:

E.g.:
[...]
    Enter Central Parallel [lat_0] (23N) :0N
 
    Enter Central Meridian [lon_0] (96W) :9E
 
Enter Scale Factor at the Central Meridian [k_0]  [1.0000000000]:
 
Enter False Easting [x_0]  [0.0000000000]:
 
Enter False Northing [y_0]  [0.0000000000]:
Enter plural form of units [meters]:
[...]

Now it should be easy to define the British NG.

Cheers

 Markus

PS: Recompile libgis and the modules in src/general/



On Wed, Mar 06, 2002 at 06:45:25PM +0000, David D Gray wrote:
> Markus Neteler wrote:
> 
> > Hi,
> > 
> > I have a question if we want to extend the Transverse Mercator
> > definition mode (g.setproj etc.) by false northing?
> > It seem that the UK needs the x_0 to be defined:
> > 
> 
> 
> Do you mean y_0?
> 
> It is x_0 : +400000
>        y_0 : -100000
> 
> for BNG. So yes that would be handy.
> 
> David
> 
> 
> > http://www.geocities.com/mapref/prj/uk/uk_osbg36.html
> > 
> > Also strange local map projections as found in Bolzano, Italy,
> > need false northing for Transverse Mercator.
> > 
> > If there are no objections, I would add it to
> > src/libes/gis/geo_init.c 
> > 
> > Markus
> > 
> > _______________________________________________
> > grass5 mailing list
> > grass5 at grass.itc.it
> > http://grass.itc.it/mailman/listinfo/grass5
> > 
> > 
> 
> 
> 
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