Clipped polygon

[pnorman]

These are water polygons, and the island just north of the middle is clipped. The location is 7/48.945/-123.437 and the data is ne_ocean from Natural Earth.

I'm having trouble debugging it since I'm not sure how to get what tile it is, where the tile bounds are, etc.

[ARolek]

@pnorman you can add ?debug=true to the URL (i.e. http://localhost:8080/?debug=true#7/48.945/-123.437) to encode tile outlines and a z/x/y into a point in the cent of the tile. Then you can inspect the tile.

I assume this is on v0.5.0. A lot of rendering issues were fixed in v0.6.0. Can you build off that branch and see if the same issue is happening? Build instructions

[pnorman]

I assume this is on v0.5.0. A lot of rendering issues were fixed in v0.6.0. Can you build off that branch and see if the same issue is happening? Build instructions

I tried under 0.6.0 but it might have had a cached tile, so retesting.

[pnorman]

It still happens with fd14038, and it's right on the edge between 5/5/10 and 5/5/11.

My immediate guess is an interaction between different simplification on different tiles, these being water polygons, not land polygons, and handling of the edges of tiles.

[pnorman]

Just for reference, these are the holes in the polygon

[ARolek]

@pnorman just to confirm you're using the Natural Earth Ocean data v4.0.0?

[pnorman]

I am specifically using http://www.naturalearthdata.com/http//www.naturalearthdata.com/download/50m/physical/ne_50m_ocean.zip

I first do CREATE SCHEMA IF NOT EXISTS loading; in PostgreSQL, then call ogr2ogr -f PostgreSQL -lco GEOMETRY_NAME=way -lco SPATIAL_INDEX=FALSE -lco EXTRACT_SCHEMA_FROM_LAYER_NAME=YES -nln loading.ne_ocean --config SHAPE_ENCODING WINDOWS-1252 -explodecollections -t_srs EPSG:3857 -clipsrc -179.999999999 -85.05112877980659 179.999999999 85.05112877980659 PG:dbname=gis data/ne_ocean/ne_50m_ocean.shp

PostGIS post-processing is

ALTER TABLE "loading"."ne_ocean" SET ( autovacuum_enabled = FALSE );
ALTER TABLE "loading"."ne_ocean" DROP COLUMN ogc_fid;
DELETE FROM "loading"."ne_ocean" WHERE way IS NULL;
ALTER TABLE "loading"."ne_ocean" ALTER COLUMN way SET NOT NULL;
CREATE INDEX "ne_ocean_geohash"
  ON "loading"."ne_ocean"
  (ST_GeoHash(ST_Transform(ST_Envelope(way),4326),10) COLLATE "C");
CLUSTER "loading"."ne_ocean" USING "ne_ocean_geohash";
DROP INDEX "loading"."ne_ocean_geohash";
CREATE INDEX ON "loading"."ne_ocean" USING GIST (way) WITH (fillfactor=100);
ANALYZE "loading"."ne_ocean"
ALTER TABLE "loading"."ne_ocean" SET ( autovacuum_enabled = FALSE );