Message-ID: <2f0075b5-d1f8-0eae-21f5-98c0e8ad4461@uni-muenster.de>
Date: 2023-01-25T17:49:21Z
From: Edzer Pebesma
Subject: Re-scale units of coordinates in sf geometry?
In-Reply-To: <f21f4f5d169b4a298639f827d460a4810cfcaa97.camel@gmail.com>
I guess the question is: "safe for what?" - if numerical errors are a
problem without rescaling, then you should do it. You might be able to
choose the rescaling factor such that these errors are minimized.
On 25/01/2023 18:37, Steve Gutreuter wrote:
> Is it safe to re-scale sf geometry coordinates from meters to
> kilometers using, for example:
>
> sfobj$geometry <- sfobj$geometry / 1000
>
> It seems to work, but I understand too little about spatial data to
> know whether that practice is actually safe. I am working with spatial
> data in a continental-scale equidistant conic projection, and the units
> are meters. It seems that kilometers would be better suited stochastic
> partial differential equation modeling on a finite-element mesh, but
> maybe that is a moot point.
>
> Any and all advice will be much appreciated.
>
> Thanks!
--
Edzer Pebesma
Institute for Geoinformatics
Heisenbergstrasse 2, 48151 Muenster, Germany
Phone: +49 251 8333081