Mercurial > gemma
view pkg/octree/strtree.go @ 2624:9dbaf69c7a66
Improve geoserver config to better calculate bounding boxes
* Disable the use of estimated extents for the postgis storage
configuration for geoserver, which is set via the gemma middleware.
This way we are able to get better bounding boxes for many layers
where the postgis function `ST_EstimatedExtent()` would be far off.
author | Bernhard Reiter <bernhard@intevation.de> |
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date | Wed, 13 Mar 2019 16:18:39 +0100 |
parents | 114979e97a6c |
children | f456ce0a6a0e |
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// This is Free Software under GNU Affero General Public License v >= 3.0 // without warranty, see README.md and license for details. // // SPDX-License-Identifier: AGPL-3.0-or-later // License-Filename: LICENSES/AGPL-3.0.txt // // Copyright (C) 2018 by via donau // – Österreichische Wasserstraßen-Gesellschaft mbH // Software engineering by Intevation GmbH // // Author(s): // * Sascha L. Teichmann <sascha.teichmann@intevation.de> package octree import ( "math" "sort" ) const numEntries = 8 type STRTree struct { tin *Tin index []int32 bboxes []Box2D } func (s *STRTree) Build(t *Tin) { s.tin = t all := make([]int32, len(t.Triangles)) for i := range all { all[i] = int32(i) } s.index = append(s.index, 0) root := s.build(all) s.index[0] = root } func (s *STRTree) Clip(p *Polygon) map[int32]struct{} { removed := make(map[int32]struct{}) stack := []int32{s.index[0]} vertices := s.tin.Vertices for len(stack) > 0 { top := stack[len(stack)-1] stack = stack[:len(stack)-1] if top > 0 { // node switch p.IntersectionBox2D(s.bbox(top)) { case IntersectionInside: // all triangles are inside polygon case IntersectionOutSide: // all triangles are outside polygon s.allTriangles(top, removed) default: // mixed bag for i, n := int32(0), s.index[top+1]; i < n; i++ { stack = append(stack, s.index[top+2+i]) } } } else { // leaf top = -top - 1 for i, n := int32(0), s.index[top+1]; i < n; i++ { idx := s.index[top+2+i] ti := s.tin.Triangles[idx] t := Triangle{ vertices[ti[0]], vertices[ti[1]], vertices[ti[2]], } if p.IntersectionWithTriangle(&t) != IntersectionInside { removed[idx] = struct{}{} } } } } return removed } func (s *STRTree) allTriangles(pos int32, tris map[int32]struct{}) { stack := []int32{pos} for len(stack) > 0 { top := stack[len(stack)-1] stack = stack[:len(stack)-1] if top > 0 { // node for i, n := int32(0), s.index[top+1]; i < n; i++ { stack = append(stack, s.index[top+2+i]) } } else { // leaf top = -top - 1 for i, n := int32(0), s.index[top+1]; i < n; i++ { tris[s.index[top+2+i]] = struct{}{} } } } } func (s *STRTree) build(items []int32) int32 { sort.Slice(items, func(i, j int) bool { ti := s.tin.Triangles[items[i]] tj := s.tin.Triangles[items[j]] return s.tin.Vertices[ti[0]].X < s.tin.Vertices[tj[0]].X }) P := int(math.Ceil(float64(len(items)) / float64(numEntries))) S := int(math.Ceil(math.Sqrt(float64(P)))) slices := strSplit(items, S) leaves := strJoin( slices, S, func(i, j int32) bool { ti := s.tin.Triangles[i] tj := s.tin.Triangles[j] return s.tin.Vertices[ti[0]].Y < s.tin.Vertices[tj[0]].Y }, s.allocLeaf, ) return s.buildNodes(leaves) } func (s *STRTree) buildNodes(items []int32) int32 { if len(items) <= numEntries { return s.allocNode(items) } sort.Slice(items, func(i, j int) bool { return s.bbox(items[i]).X1 < s.bbox(items[j]).X1 }) P := int(math.Ceil(float64(len(items)) / float64(numEntries))) S := int(math.Ceil(math.Sqrt(float64(P)))) slices := strSplit(items, S) nodes := strJoin( slices, S, func(i, j int32) bool { return s.bbox(i).Y1 < s.bbox(j).Y1 }, s.allocNode, ) return s.buildNodes(nodes) } func (s *STRTree) bbox(idx int32) Box2D { if idx < 0 { // Don't care if leaf or node. idx = -idx - 1 } return s.bboxes[s.index[idx]] } func strSplit(items []int32, S int) [][]int32 { sm := S * numEntries slices := make([][]int32, S) for i := range slices { var n int if l := len(items); l < sm { n = l } else { n = sm } slices[i] = items[:n] items = items[n:] } return slices } func strJoin( slices [][]int32, S int, less func(int32, int32) bool, alloc func([]int32) int32, ) []int32 { nodes := make([]int32, 0, S*S) for _, slice := range slices { sort.Slice(slice, func(i, j int) bool { return less(slice[i], slice[j]) }) for len(slice) > 0 { var n int if l := len(slice); l >= numEntries { n = numEntries } else { n = l } nodes = append(nodes, alloc(slice[:n])) slice = slice[n:] } } return nodes } func (s *STRTree) allocNode(items []int32) int32 { pos := len(s.index) s.index = append(s.index, 0, int32(len(items))) s.index = append(s.index, items...) if len(items) > 0 { box := s.bbox(items[0]) for i := 1; i < len(items); i++ { box = box.Union(s.bbox(items[i])) } s.index[pos] = int32(s.allocBBox(box)) } return int32(pos) } func (s *STRTree) allocBBox(box Box2D) int { pos := len(s.bboxes) s.bboxes = append(s.bboxes, box) return pos } func (s *STRTree) allocLeaf(items []int32) int32 { pos := len(s.index) s.index = append(s.index, 0, int32(len(items))) s.index = append(s.index, items...) if len(items) > 0 { vertices := s.tin.Vertices ti := s.tin.Triangles[items[0]] t := Triangle{ vertices[ti[0]], vertices[ti[1]], vertices[ti[2]], } box := t.BBox() for i := 1; i < len(items); i++ { it := items[i] ti := s.tin.Triangles[it] t := Triangle{ vertices[ti[0]], vertices[ti[1]], vertices[ti[2]], } box = box.Union(t.BBox()) } s.index[pos] = int32(s.allocBBox(box)) } return int32(-(pos + 1)) }