Re: [R-sig-Geo] generating coordinates at equal geographical distances

2013-09-15 Thread Robert J. Hijmans
And you can compare the results with those of the 'regularCoordinates' function in geosphere. Robert On Sat, Aug 31, 2013 at 1:05 PM, Edzer Pebesma wrote: > -BEGIN PGP SIGNED MESSAGE- > Hash: SHA1 > > John, as an alternative you may want to look into sp::spsample, using > type "Fibonacci

Re: [R-sig-Geo] generating coordinates at equal geographical distances

2013-08-31 Thread Edzer Pebesma
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 John, as an alternative you may want to look into sp::spsample, using type "Fibonacci"; the paper describing this is Alvaro Gonzalez, 2010. Measurement of Areas on a Sphere Using Fibonacci and Latitude-Longitude Lattices. Mathematical Geosciences 42(1

Re: [R-sig-Geo] generating coordinates at equal geographical distances

2013-08-28 Thread Michael Sumner
There are many pathways to this, but you could use a map projection that provides the properties you want and sample points there, then project that back to longitude latitude. Here's a dummy example, I just found an equal area projection by stumbling through spatialreference.org, you should look

Re: [R-sig-Geo] generating coordinates at equal geographical distances

2013-08-28 Thread john d
Ok, I'll be more explicit :) If I want to generate random coordinates across North America by uniformly sampling latitudes and longitudes, the geographical distance between these coordinates would decrease towards higher latitudes. I'd like to be able to generate coordinates (e.g. a grid) such tha

Re: [R-sig-Geo] generating coordinates at equal geographical distances

2013-08-28 Thread Barry Rowlingson
You will find that any two coordinates are equidistant from each other... So my suggestion is you need to expand you question a bit more! :) On Wed, Aug 28, 2013 at 3:49 PM, john d wrote: > Dear all, > > I need to generate coordinates that are equidistant, regardless of > latitude. Any suggesti

[R-sig-Geo] generating coordinates at equal geographical distances

2013-08-28 Thread john d
Dear all, I need to generate coordinates that are equidistant, regardless of latitude. Any suggestions? Thanks! John [[alternative HTML version deleted]] ___ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo