Bookmark and Share

Notice: On March 31, it was announced that Statalist is moving from an email list to a forum. The old list will shut down at the end of May, and its replacement, statalist.org is already up and running.


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: st: Gen Randomized geo coordinates within a range


From   Maarten Buis <maartenlbuis@gmail.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Gen Randomized geo coordinates within a range
Date   Fri, 19 Aug 2011 12:36:25 +0200

On Fri, Aug 19, 2011 at 11:17 AM,  <graupel75@gmail.com> wrote:
> I need to generate a set of random geographic coordinates (x,y) given
> a central point, within a given range.

Alternatively, if you want your range to be a circle with radius .5
you can do so as below

*-------------- begin example --------------
clear
input x y
1 1
5 5
1 5
end

forvalues i = 1/30 {
	local phi = 2*runiform()*_pi
	local r = .5*runiform()
	gen xran`i' = `r'*cos(`phi') + x
	gen yran`i' = `r'*sin(`phi') + y
	local gr `"`gr' || scatter yran`i' xran`i'"'
}
scatter y x, aspect(1) `gr'
*-------------- end example -----------------
(For more on examples I sent to the Statalist see:
http://www.maartenbuis.nl/example_faq )

Hope this helps,
Maarten

--------------------------
Maarten L. Buis
Institut fuer Soziologie
Universitaet Tuebingen
Wilhelmstrasse 36
72074 Tuebingen
Germany


http://www.maartenbuis.nl
--------------------------
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/


© Copyright 1996–2014 StataCorp LP   |   Terms of use   |   Privacy   |   Contact us   |   Site index