[mapserver-users] Google Mercator and +nadgrids=@null

[Rahkonen Jukka]

Hi,

I have in my epsg file the following line for Google Mercator
projection:

<900913> +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0
+x_0=0.0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +no_defs

I have copied the definitions from somewhere, I do not remember where.
Now I noticed that http://spatialreference.org/ref/epsg/3785/proj4/
gives this proj4 string:

+proj=merc +lon_0=0 +k=1 +x_0=0 +y_0=0 +a=6378137 +b=6378137
+towgs84=0,0,0,0,0,0,0 +units=m +no_defs 

There seems to be one difference: my line has +nadgrids=@null while the
Spatialreference one has +towgs84=0,0,0,0,0,0,0 instead. Do they mean
just the same thing?

-Jukka Rahkonen-