|
1
|
|
|
<?php |
|
2
|
|
|
/** |
|
3
|
|
|
* PHPCoord. |
|
4
|
|
|
* |
|
5
|
|
|
* @author Doug Wright |
|
6
|
|
|
*/ |
|
7
|
|
|
declare(strict_types=1); |
|
8
|
|
|
|
|
9
|
|
|
namespace PHPCoord\CoordinateOperation; |
|
10
|
|
|
|
|
11
|
|
|
use PHPCoord\UnitOfMeasure\Length\Metre; |
|
12
|
|
|
use SplFileObject; |
|
13
|
|
|
|
|
14
|
|
|
use function in_array; |
|
15
|
|
|
use function substr; |
|
16
|
|
|
use function unpack; |
|
17
|
|
|
|
|
18
|
|
|
/** |
|
19
|
|
|
* @see https://vdatum.noaa.gov/docs/gtx_info.html for documentation |
|
20
|
|
|
*/ |
|
21
|
|
|
class GTXGrid extends GeographicGeoidHeightGrid |
|
22
|
|
|
{ |
|
23
|
|
|
use BilinearInterpolation; |
|
24
|
|
|
|
|
25
|
|
|
private int $headerLength; |
|
26
|
|
|
private string $shiftDataType; |
|
27
|
|
|
|
|
28
|
10 |
|
public function __construct($filename) |
|
29
|
|
|
{ |
|
30
|
10 |
|
$this->gridFile = new SplFileObject($filename); |
|
31
|
10 |
|
$this->storageOrder = self::STORAGE_ORDER_INCREASING_LONGITUDE_INCREASING_LATIITUDE; |
|
32
|
|
|
|
|
33
|
10 |
|
$header = $this->getHeader(); |
|
34
|
10 |
|
$this->startX = $header['xlonsw']; |
|
35
|
10 |
|
$this->startY = $header['xlatsw']; |
|
36
|
10 |
|
$this->numberOfColumns = $header['nlon']; |
|
37
|
10 |
|
$this->numberOfRows = $header['nlat']; |
|
38
|
10 |
|
$this->columnGridInterval = $header['dlon']; |
|
39
|
10 |
|
$this->rowGridInterval = $header['dlat']; |
|
40
|
|
|
|
|
41
|
10 |
|
if ($this->startX > 180) { // normalise if necessary |
|
42
|
2 |
|
$this->startX -= 360; |
|
43
|
|
|
} |
|
44
|
|
|
} |
|
45
|
|
|
|
|
46
|
|
|
/** |
|
47
|
|
|
* @return Metre[] |
|
48
|
|
|
*/ |
|
49
|
10 |
|
public function getValues($x, $y): array |
|
50
|
|
|
{ |
|
51
|
10 |
|
$shift = $this->interpolate($x, $y)[0]; |
|
52
|
|
|
|
|
53
|
|
|
// These are in millimeters for some reason... :/ |
|
54
|
10 |
|
if (in_array($this->gridFile->getBasename(), ['vertconc.gtx', 'vertcone.gtx', 'vertconw.gtx'], true)) { |
|
55
|
1 |
|
$shift /= 1000; |
|
56
|
|
|
} |
|
57
|
|
|
|
|
58
|
10 |
|
return [new Metre($shift)]; |
|
59
|
|
|
} |
|
60
|
|
|
|
|
61
|
10 |
|
private function getRecord(int $longitudeIndex, int $latitudeIndex): GridValues |
|
|
|
|
|
|
62
|
|
|
{ |
|
63
|
10 |
|
$recordId = match ($this->storageOrder) { |
|
64
|
10 |
|
self::STORAGE_ORDER_INCREASING_LATITUDE_INCREASING_LONGITUDE => $longitudeIndex * $this->numberOfRows + $latitudeIndex, |
|
65
|
10 |
|
self::STORAGE_ORDER_INCREASING_LONGITUDE_DECREASING_LATIITUDE => ($this->numberOfRows - $latitudeIndex - 1) * $this->numberOfColumns + $longitudeIndex, |
|
66
|
10 |
|
self::STORAGE_ORDER_INCREASING_LONGITUDE_INCREASING_LATIITUDE => $latitudeIndex * $this->numberOfColumns + $longitudeIndex, |
|
67
|
|
|
}; |
|
68
|
|
|
|
|
69
|
10 |
|
$offset = $this->headerLength + $recordId * 4; |
|
70
|
10 |
|
$this->gridFile->fseek($offset); |
|
71
|
10 |
|
$rawRow = $this->gridFile->fread(4); |
|
72
|
10 |
|
$data = unpack("{$this->shiftDataType}shift", $rawRow); |
|
73
|
|
|
|
|
74
|
10 |
|
return new GridValues( |
|
75
|
10 |
|
$longitudeIndex * $this->columnGridInterval + $this->startX, |
|
76
|
10 |
|
$latitudeIndex * $this->rowGridInterval + $this->startY, |
|
77
|
10 |
|
[$data['shift']] |
|
78
|
|
|
); |
|
79
|
|
|
} |
|
80
|
|
|
|
|
81
|
10 |
|
private function getHeader(): array |
|
82
|
|
|
{ |
|
83
|
10 |
|
$this->gridFile->fseek(0); |
|
84
|
10 |
|
$rawHeader = $this->gridFile->fread(44); |
|
85
|
10 |
|
$ikind = substr($rawHeader, 40, 4); |
|
86
|
10 |
|
if (unpack('Nikind', $ikind)['ikind'] === 1) { // big endian |
|
87
|
|
|
$this->headerLength = 44; |
|
88
|
|
|
$this->shiftDataType = 'G'; |
|
89
|
|
|
$data = unpack('Exlatsw/Exlonsw/Edlat/Edlon/Nnlat/Nnlon', $rawHeader); |
|
90
|
10 |
|
} elseif (unpack('Vikind', $ikind)['ikind'] === 1) { // little endian |
|
91
|
1 |
|
$this->headerLength = 44; |
|
92
|
1 |
|
$this->shiftDataType = 'g'; |
|
93
|
1 |
|
$data = unpack('exlatsw/exlonsw/edlat/edlon/Vnlat/Vnlon', $rawHeader); |
|
94
|
|
|
} else { // not all files (e.g. NZ) have this endian check column, assume big endian |
|
95
|
9 |
|
$this->headerLength = 40; |
|
96
|
9 |
|
$this->shiftDataType = 'G'; |
|
97
|
9 |
|
$data = unpack('Exlatsw/Exlonsw/Edlat/Edlon/Nnlat/Nnlon', $rawHeader); |
|
98
|
|
|
} |
|
99
|
|
|
|
|
100
|
10 |
|
return $data; |
|
101
|
|
|
} |
|
102
|
|
|
} |
|
103
|
|
|
|
dvdoug /
PHPCoord
This check looks for private methods that have been defined, but are not used inside the class.