[GRASSLIST:5752] Re: mercator coordinates

[Ivan Teliatnikov]

On Thu, 6 Mar 2003, Glynn Clements wrote:

Glynn,

Could you please repost this message, I only got half of your message.

Thank you,

Ivan.

> 
> grass grass wrote:
> 
> > > We are brand new grass users and we would like some advice on how to open a
> > > mercator map in grass (if it is not a UTM) with longitude and latitude
> > > coordinates instead of this weird easting and northing stuff that seems to
> > > come up when you use d.where.
> 
> It can't be done.
> 
> GRASS uses linear coordinates but, for the Mercator projection,
> degrees of latitude get further apart the further you get from the
> equator (y is proportional to log(tan(latitude))).
> 
> AFAIK, the only projection for which projected coordinates have a
> linear relationship to lat-lon coordinates is Equidistant Cylindrical
> (Plate Car

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Ivan Teliatnikov

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