What geographic projection is used in GREAT-ER

[Jan-Oliver Wagner]

Hi Johan,

On Thu, Jun 12, 2003 at 11:30:09AM +0100, Johan Olanders wrote:
> I wonder what geographic projection is used in GREAT-ER.

GREAT-ER uses geographic coordinates as a basis.
This is acutally no projection but really the raw data.
Decimal degrees is the unit.

> I understand that I need to have the coordinates expressed as longitude and
> latitude in decimal degrees, but what geographic projection is used. The
> formula I'm planning to use for converting from UK national grid references
> to longitude latitude needs information such as:

Your GIS should be able to perform the transformation from UK National
Grid to geographic coordinates quite easily. I recommend not to
develop your own algorithm (too much work and error-prone).

You may use the Free Software tool PROJ as a command line tool
	http://www.remotesensing.org/proj

You may want to try to install a rpm of proj:
ftp://ftp.intevation.de/freegis/gnu-linux-i586/freegis-1.2.3/i386/PROJ-4.4.7-1.i386.rpm

> I guess that this information is available somewhere as soon as I know what
> projection is used. I want "my" catchment to show up at the right place!

Hope my hints help to get the catchment done soon :-)

Best

	Jan
-- 
Jan-Oliver Wagner               http://intevation.de/~jan/

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