Clip tileset to a polygonal boundary #351
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| tiledGeometries = new HashMap<>(); | ||
| coverings = new HashMap<>(); | ||
| try { | ||
| for (var i = 0; i <= 15; i++) { |
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Need to get min/max from the actual program somewhere.
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| public Clip(Stats stats, Geometry input) { | ||
| this.stats = stats; | ||
| var clipGeometry = latLonToWorldCoords(input).buffer(0.00001); |
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Maybe this should be configurable buffer size via arguments?
| var extents = TileExtents.computeFromWorldBounds(i, WORLD_BOUNDS); | ||
| double scale = 1 << i; | ||
| Geometry scaled = AffineTransformation.scaleInstance(scale, scale).transform(clipGeometry); | ||
| // var simplified = DouglasPeuckerSimplifier.simplify(scaled, 0.25/256); |
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Do we need to simplify, or rely on the last snapping step?
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I would be surprised if we had to.
| double scale = 1 << i; | ||
| Geometry scaled = AffineTransformation.scaleInstance(scale, scale).transform(clipGeometry); | ||
| // var simplified = DouglasPeuckerSimplifier.simplify(scaled, 0.25/256); | ||
| this.tiledGeometries.put(i, sliceIntoTiles(scaled, 0, 0.015625, i, extents.getForZoom(i)).getTileData()); |
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We hardcode the buffer size here. We need a way to determine the actual buffer size taking into account any custom buffer size determination function.
| } | ||
| } | ||
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| // Copied from elsewhere in planetiler |
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we could make these public in planetiler-core?
| if (this.tiledGeometries.containsKey(tileCoord.z()) && this.tiledGeometries.get(tileCoord.z()).containsKey(tileCoord)) { | ||
| List<List<CoordinateSequence>> coords = tiledGeometries.get(tileCoord.z()).get(tileCoord); | ||
| var clipGeometry = reassemblePolygons(coords); | ||
| var clipGeometry2 = GeoUtils.fixPolygon(clipGeometry); |
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fixPolygon seems to work fine here instead of needing snapAndFixPolygon
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Do you store the clipping mask in world coordinates (web mercator x y of the 0/0/0 tile) or do you store it in tile coordinates? |
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I saw you have a covering tiles mechanism. I think you could get rid of this by using an STRtree https://locationtech.github.io/jts/javadoc/org/locationtech/jts/index/strtree/STRtree.html and use the tile bounds as an envelope for querying |
Implements #51
This is to address making non-global maps: for example, a map of a single continent, country, or city. The existing tooling has a path to doing this with
pmtiles extracton a planet file, but this has a downside: the output tileset is not clipped to the AOI (area of interest) and shows the entire detail of the original source tileset at lower zoom levels.Additionally, if the input OSM data has features that lie outside of the AOI, like oceans or roads, those extend beyond the boundary. This is not a fatal problem for many use cases, but we can do better in our tile generation program by clipping every feature to the AOI.
The challenges here are: