From 197f3a26d9f6332b2cb738fcde4b65e8364d27c4 Mon Sep 17 00:00:00 2001 From: felixpalmer Date: Tue, 19 Apr 2022 15:51:30 +0200 Subject: [PATCH] Add section on winding order (#59) Co-authored-by: Tim Schaub --- format-specs/geoparquet.md | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/format-specs/geoparquet.md b/format-specs/geoparquet.md index d1ee2c8..4fab31c 100644 --- a/format-specs/geoparquet.md +++ b/format-specs/geoparquet.md @@ -147,6 +147,10 @@ specify "MultiPolygon", but it is expected to specify ["Polygon", "MultiPolygon"]. Or if having 3D points, it is not sufficient to specify "Point", but it is expected to list "Point Z". +#### Polygon winding + +The winding order of polygons follows the [GeoJSON spec](https://datatracker.ietf.org/doc/html/rfc7946#section-3.1.6). Polygon rings MUST follow the right-hand rule for orientation (counterclockwise external rings, clockwise internal rings). Traversing vertices of rings in order, the interior of the polygon is on the left. + #### edges This attribute indicates how to interpret the edges of the geometries: whether the line between two points is a straight cartesian line or the shortest line on the sphere (geodesic line). Available values are: