[Proj] wgs84 northings and eastings

Roger Oberholtzer roger at opq.se
Thu May 26 09:58:22 EST 2011

On Thu, 2011-05-26 at 13:27 +0000, Mikael Rittri wrote:

> You write "transverse mercator", but it seems you mean 
> ordinary mercator (Web Mercator, to be specific). 

My mistake. I was doing other work at the same time with transverse
mercator. Parallel work is not always a good thing.

> So, you have to use a trick: use 
>    +nadgrids=@null 

I remember the discussion a while back. Would I then remove the
+towgs84=0,0,0,0,0,0,0 as well? Or do I need both?

> instead. See 
> http://trac.osgeo.org/proj/wiki/FAQ#ChangingEllipsoidWhycantIconvertfromWGS84toGoogleEarthVirtualGlobeMercator

Following that link eventually led me to:

which it calls World Mercator. The definition is:

	+proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs

Since my source data is defined as:

	+proj=latlong +datum=WGS84

perhaps this more suited to my original goal?

Yours sincerely,

Roger Oberholtzer

OPQ Systems / Ramböll RST

Office: Int +46 10-615 60 20
Mobile: Int +46 70-815 1696
roger.oberholtzer at ramboll.se

Ramböll Sverige AB
Krukmakargatan 21
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SE-104 62 Stockholm, Sweden

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