[gdal-dev] S57 questions

[Frank Warmerdam]

ogr user wrote:
> This patch does not do anything regarding direction of winding.
> 
> What it does is - discover the exterior ring for a polygon, and make it
> the first ring in the polygon object. This was in response to your
> earlier comment that said "The S-57 driver uses
> OGRBuildPolygonFromEdges() to form the set of lines into a polygon.  No
> effort is currently made to properly represent exterior vs. interior
> rings as is required by the simple features geometry specification."
> 
> This is that effort. FWIW, with this patch, polygons read from ENC data
> that were assembled "out of order" (i.e. exterior ring was assembled
> later than a first one) would be rearranged (in that exterior ring is
> found and made the "exterior" ring) so that they could be drawn/handled
> correctly using OGR geometry.

Mike,

This would indeed be a useful change. I'd encourage you to file it in Trac
and I'll look at incorporating it.

Best regards,
-- 
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