Compile sf in windows with liblwgeom

On 16/09/17 18:22, Barry Rowlingson wrote:

On Sat, Sep 16, 2017 at 3:45 PM, Edzer Pebesma
<edzer.pebesma at uni-muenster.de <mailto:edzer.pebesma at uni-muenster.de>>
wrote:



    On 16/09/17 15:20, Eduardo Diez wrote:

    > Dear list,
    > I have a MULTIPOLYGON geometry set where the rings are in the wrong
    > direction and would like to correct that with *st_make_valid*. As I'm in
    > Windows and use the binary version of the *sf* package it gives me the
    > error:
    >

    >> sp2 = st_make_valid(sp1)

    > Error in CPL_make_valid(x) :
    >   st_make_valid requires compilation against liblwgeom
    >
    > Is there a series of steps I can follow for compiling *sf* in Windows
    > linked to liblwgeom?

    No, and I also don't think that st_make_valid does this.


st_make_valid certainly did something:

https://gis.stackexchange.com/questions/254836/sf-lines-to-polygons-with-holes

I only tried a single outer ring in both directions, and it didn't
revert them. Maybe it only reverts if if outer and inner ring have the
same direction.

I've just added an edit to my answer there with the sp-and-back round
trip, which seems to work, but its not exactly the most satisfying solution.

It would be fairly trivial to move some of the code to sf - at a
performance penalty if we'd do the check always, like sp does.

What's the problem with liblwgeom on Windows?

It's not part of the rwinlib collection at https://github.com/rwinlib ;
I'll bring it up with Jeroen next time I see him. lwgeom has more good
things than what sf uses.

Barry