[GRASSLIST:10320] Re: robinson (winkel) projection

[Ian MacMillan]

Otto, I have made some robinson locations for my work, and the process 
is pretty straight forward.  After selecting 'create new location' when 
first opening grass, select that you would like to use 'Other 
Projection' when asked for your coord. system.  When asked to specify 
your projection name, just use 'robin'.  Select your datum as usual.  
You will then have to input your central parallel, central meridian, 
and preferred units.  For most robinson projections that you see in 
atlases, the central parallel is the equator (0), and the central 
meridian is the Greenwich meridian (also 0).  I usually use meters as 
my preferred units.

Degrees would be really nice as a standard unit for these kinds of 
projections, but since their absolute length varies depending on your 
location on the earth, they can't be used in grass.  My workaround to 
this has been to make a vector grid in a latlong location that is 
spaced about ten or fifteen degrees apart for the entire earth.  I then 
project (with v.proj) that vector file into my robinson location as a 
first step so that I can see where I am in the world.

Once you are done with all of that, use r.proj and v.proj at your 
leisure in your new location.

Hope this helps,
Ian

On Feb 15, 2006, at 4:25 AM, Otto Dassau wrote:

> Hi,
>
> I would like to convert a lat/lon map into a robinson (winkel) 
> projection.
>
> does anybody has experience with the creation of a robinson (winkel)
> projektion in GRASS? It seems to be supported (robin, winkel,...) but I
> haven't found out, how to create a robin location in GRASS and which
> parameters a normaly used.
>
> thanks
>   Otto
>
>
>
>
 >
 >
What happens if a big asteroid hits Earth? Judging from realistic 
simulations involving a sledge hammer and a common laboratory frog, we 
can assume it will be pretty bad.
  - Dave Barry


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