|
1
|
|
|
<?php |
|
2
|
|
|
/** |
|
3
|
|
|
* Class PolylineSimplifyer |
|
4
|
|
|
* |
|
5
|
|
|
* @created 04.10.2019 |
|
6
|
|
|
* @author smiley <[email protected]> |
|
7
|
|
|
* @copyright 2019 smiley |
|
8
|
|
|
* @license MIT |
|
9
|
|
|
*/ |
|
10
|
|
|
|
|
11
|
|
|
namespace chillerlan\GeoJSON; |
|
12
|
|
|
|
|
13
|
|
|
use function array_fill, array_pop, array_push, array_values, count, is_array; |
|
14
|
|
|
|
|
15
|
|
|
/** |
|
16
|
|
|
* @see https://github.com/mourner/simplify-js |
|
17
|
|
|
*/ |
|
18
|
|
|
class PolylineSimplifyer{ |
|
19
|
|
|
|
|
20
|
|
|
protected array $coords; |
|
21
|
|
|
|
|
22
|
|
|
/** |
|
23
|
|
|
* PolylineSimplifyer constructor. |
|
24
|
|
|
* |
|
25
|
|
|
* @throws \chillerlan\GeoJSON\GeoJSONException |
|
26
|
|
|
*/ |
|
27
|
|
|
public function __construct(array $polylineCoords){ |
|
28
|
|
|
|
|
29
|
|
|
if(count($polylineCoords) < 2){ |
|
30
|
|
|
throw new GeoJSONException('not enough points'); |
|
31
|
|
|
} |
|
32
|
|
|
|
|
33
|
|
|
$this->coords = array_values($polylineCoords); |
|
34
|
|
|
|
|
35
|
|
|
foreach($this->coords as $i => $coord){ |
|
36
|
|
|
|
|
37
|
|
|
if(!is_array($coord) || count($coord) < 2){ |
|
38
|
|
|
throw new GeoJSONException('invalid coords found'); |
|
39
|
|
|
} |
|
40
|
|
|
|
|
41
|
|
|
$this->coords[$i] = array_values($coord); |
|
42
|
|
|
} |
|
43
|
|
|
|
|
44
|
|
|
} |
|
45
|
|
|
|
|
46
|
|
|
/** |
|
47
|
|
|
* @throws \chillerlan\GeoJSON\GeoJSONException |
|
48
|
|
|
*/ |
|
49
|
|
|
public function simplify(float $tolerance = 1, bool $highestQuality = false):array{ |
|
50
|
|
|
$sqTolerance = $tolerance * $tolerance; |
|
51
|
|
|
$points = $highestQuality ? $this->coords : $this->simplifyRadialDist($sqTolerance); |
|
52
|
|
|
|
|
53
|
|
|
return $this->simplifyDouglasPeucker($points, $sqTolerance); |
|
54
|
|
|
} |
|
55
|
|
|
|
|
56
|
|
|
/** |
|
57
|
|
|
* basic distance-based simplification |
|
58
|
|
|
*/ |
|
59
|
|
|
protected function simplifyRadialDist(float $sqTolerance):array{ |
|
60
|
|
|
$prevPoint = $this->coords[0]; |
|
61
|
|
|
$newPoints = [$prevPoint]; |
|
62
|
|
|
$point = null; |
|
63
|
|
|
$len = count($this->coords); |
|
64
|
|
|
|
|
65
|
|
|
for($i = 1; $i < $len; $i++){ |
|
66
|
|
|
$point = $this->coords[$i]; |
|
67
|
|
|
|
|
68
|
|
|
if($this->getSqDist($point, $prevPoint) > $sqTolerance){ |
|
69
|
|
|
$newPoints[] = $point; |
|
70
|
|
|
$prevPoint = $point; |
|
71
|
|
|
} |
|
72
|
|
|
} |
|
73
|
|
|
|
|
74
|
|
|
if($prevPoint !== $point){ |
|
75
|
|
|
$newPoints[] = $point; |
|
76
|
|
|
} |
|
77
|
|
|
|
|
78
|
|
|
return $newPoints; |
|
79
|
|
|
} |
|
80
|
|
|
|
|
81
|
|
|
/** |
|
82
|
|
|
* square distance between 2 points |
|
83
|
|
|
*/ |
|
84
|
|
|
protected function getSqDist(array $p1, array $p2):float{ |
|
85
|
|
|
$dx = $p1[0] - $p2[0]; |
|
86
|
|
|
$dy = $p1[1] - $p2[1]; |
|
87
|
|
|
|
|
88
|
|
|
return $dx * $dx + $dy * $dy; |
|
89
|
|
|
} |
|
90
|
|
|
|
|
91
|
|
|
/** |
|
92
|
|
|
* simplification using optimized Douglas-Peucker algorithm with recursion elimination |
|
93
|
|
|
*/ |
|
94
|
|
|
protected function simplifyDouglasPeucker(array $points, float $sqTolerance):array{ |
|
95
|
|
|
$len = count($points); |
|
96
|
|
|
$markers = array_fill(0, $len - 1, null); |
|
97
|
|
|
$first = 0; |
|
98
|
|
|
$last = $len - 1; |
|
99
|
|
|
$stack = []; |
|
100
|
|
|
$newPoints = []; |
|
101
|
|
|
$index = 0; |
|
102
|
|
|
|
|
103
|
|
|
$markers[$first] = $markers[$last] = 1; |
|
104
|
|
|
|
|
105
|
|
|
while($last){ |
|
106
|
|
|
|
|
107
|
|
|
$maxSqDist = 0; |
|
108
|
|
|
|
|
109
|
|
|
for($i = $first + 1; $i < $last; $i++){ |
|
110
|
|
|
$sqDist = $this->getSqSegDist($points[$i], $points[$first], $points[$last]); |
|
111
|
|
|
|
|
112
|
|
|
if($sqDist > $maxSqDist){ |
|
113
|
|
|
$index = $i; |
|
114
|
|
|
$maxSqDist = $sqDist; |
|
115
|
|
|
} |
|
116
|
|
|
} |
|
117
|
|
|
|
|
118
|
|
|
if($maxSqDist > $sqTolerance){ |
|
119
|
|
|
$markers[$index] = 1; |
|
120
|
|
|
array_push($stack, $first, $index, $index, $last); |
|
121
|
|
|
} |
|
122
|
|
|
|
|
123
|
|
|
$last = array_pop($stack); |
|
124
|
|
|
$first = array_pop($stack); |
|
125
|
|
|
} |
|
126
|
|
|
|
|
127
|
|
|
foreach($points as $i => $point){ |
|
128
|
|
|
if($markers[$i]){ |
|
129
|
|
|
$newPoints[] = $point; |
|
130
|
|
|
} |
|
131
|
|
|
} |
|
132
|
|
|
|
|
133
|
|
|
return $newPoints; |
|
134
|
|
|
} |
|
135
|
|
|
|
|
136
|
|
|
/** |
|
137
|
|
|
* square distance from a point to a segment |
|
138
|
|
|
*/ |
|
139
|
|
|
protected function getSqSegDist(array $p, array $p1, array $p2):float{ |
|
140
|
|
|
$x = $p1[0]; |
|
141
|
|
|
$y = $p1[1]; |
|
142
|
|
|
$dx = $p2[0] - $x; |
|
143
|
|
|
$dy = $p2[1] - $y; |
|
144
|
|
|
|
|
145
|
|
|
if((int)$dx !== 0 || (int)$dy !== 0){ |
|
146
|
|
|
|
|
147
|
|
|
$t = (($p[0] - $x) * $dx + ($p[1] - $y) * $dy) / ($dx * $dx + $dy * $dy); |
|
148
|
|
|
|
|
149
|
|
|
if($t > 1){ |
|
150
|
|
|
$x = $p2[0]; |
|
151
|
|
|
$y = $p2[1]; |
|
152
|
|
|
|
|
153
|
|
|
} |
|
154
|
|
|
elseif($t > 0){ |
|
155
|
|
|
$x += $dx * $t; |
|
156
|
|
|
$y += $dy * $t; |
|
157
|
|
|
} |
|
158
|
|
|
} |
|
159
|
|
|
|
|
160
|
|
|
$dx = $p[0] - $x; |
|
161
|
|
|
$dy = $p[1] - $y; |
|
162
|
|
|
|
|
163
|
|
|
return $dx * $dx + $dy * $dy; |
|
164
|
|
|
} |
|
165
|
|
|
|
|
166
|
|
|
} |
|
167
|
|
|
|
chillerlan /
php-geojson-helpers
