[R-sig-Geo] Dividing World Map

Massimiliano Ruocco ruocco at idi.ntnu.no
Mon Oct 1 10:11:22 CEST 2012

Thanks for the answer
Yes, should be fine for me. I don't need polar areas. So shoud be fine 
to go from -80 to 80 for lat.
So an approximative idea to proceed could be the following:

1) scan all the UTM zone
2) divide the utm zone in quad of 10kmX10km

Just a question...i am not sure i really understand the UTM coord. Is 
each zone a 500kmX500km quad?

THanks again

On 10/01/2012 10:05 AM, Barry Rowlingson wrote:
> On Mon, Oct 1, 2012 at 8:09 AM, Massimiliano Ruocco <ruocco at idi.ntnu.no> wrote:
>> Dear all,
>> i would like to divide the world map in grid of equal dimension (example
>> quad of 10kmx10km). Is it correct to use the UTM coord instead of
>> lat/lon ones? Is there any drawback on doing that?
>> IS there any existing routine doing it?
>   Since we figured out that the earth isn't flat we've known its
> impossible. You can't divide a sphere into a grid like that - what are
> you going to do at the poles?
>   You can project small parts to coordinates such as UTM and divide
> into a regular square grid in those coordinates, but even those aren't
> perfect, and get less perfect nearer the poles, at which point they
> are completely wrong...
> I think UTM zones typically have a max latitude they should be used
> at, so as long as you don't care about polar bears and penguins you
> should be okay...
> Barry

Massimiliano Ruocco
PhD Student
Department of Computer and Information Science (IDI), NTNU
Office: 260  IT-bygget
Phone:(+47) 735 94168
Email:ruocco at idi.ntnu.no
Website: http://www.idi.ntnu.no/~ruocco/

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