|
1
|
|
|
<?php |
|
2
|
|
|
/** |
|
3
|
|
|
* PHPCoord. |
|
4
|
|
|
* |
|
5
|
|
|
* @author Doug Wright |
|
6
|
|
|
*/ |
|
7
|
|
|
declare(strict_types=1); |
|
8
|
|
|
|
|
9
|
|
|
namespace PHPCoord\CoordinateOperation; |
|
10
|
|
|
|
|
11
|
|
|
use SplFileObject; |
|
12
|
|
|
use UnexpectedValueException; |
|
13
|
|
|
|
|
14
|
|
|
use function unpack; |
|
15
|
|
|
|
|
16
|
|
|
class NADCON5Grid extends Grid |
|
17
|
|
|
{ |
|
18
|
|
|
use BiquadraticInterpolation; |
|
19
|
|
|
|
|
20
|
|
|
private string $gridDataType; |
|
21
|
|
|
|
|
22
|
8 |
|
public function __construct($filename) |
|
23
|
|
|
{ |
|
24
|
8 |
|
$this->gridFile = new SplFileObject($filename); |
|
25
|
|
|
|
|
26
|
8 |
|
$header = $this->getHeader(); |
|
27
|
8 |
|
$this->startX = $header['xlonsw']; |
|
28
|
8 |
|
$this->startY = $header['xlatsw']; |
|
29
|
8 |
|
$this->columnGridInterval = $header['dlon']; |
|
30
|
8 |
|
$this->rowGridInterval = $header['dlat']; |
|
31
|
8 |
|
$this->numberOfColumns = $header['nlon']; |
|
32
|
8 |
|
$this->numberOfRows = $header['nlat']; |
|
33
|
|
|
|
|
34
|
8 |
|
$this->gridDataType = match ($header['ikind']) { |
|
35
|
8 |
|
1 => 'G', |
|
36
|
8 |
|
default => throw new UnexpectedValueException("Unknown ikind: {$header['ikind']}"), |
|
37
|
8 |
|
}; |
|
38
|
|
|
} |
|
39
|
|
|
|
|
40
|
8 |
|
protected function getRecord(int $longitudeIndex, int $latitudeIndex): GridValues |
|
41
|
|
|
{ |
|
42
|
8 |
|
$startBytes = 52; |
|
43
|
8 |
|
$dataTypeBytes = $this->gridDataType === 'n' ? 2 : 4; |
|
44
|
8 |
|
$recordLength = 4 + $this->numberOfColumns * $dataTypeBytes + 4; |
|
45
|
|
|
|
|
46
|
8 |
|
$this->gridFile->fseek($startBytes + $recordLength * $latitudeIndex); |
|
47
|
8 |
|
$rawRow = $this->gridFile->fread($recordLength); |
|
48
|
8 |
|
$row = unpack("Gstartbuffer/{$this->gridDataType}{$this->numberOfColumns}lon/Gendbuffer", $rawRow); |
|
49
|
|
|
|
|
50
|
8 |
|
return new GridValues( |
|
51
|
8 |
|
$longitudeIndex * $this->columnGridInterval + $this->startX, |
|
52
|
8 |
|
$latitudeIndex * $this->rowGridInterval + $this->startY, |
|
53
|
8 |
|
[$row['lon' . ($longitudeIndex + 1)]] |
|
54
|
8 |
|
); |
|
55
|
|
|
} |
|
56
|
|
|
|
|
57
|
8 |
|
private function getHeader(): array |
|
58
|
|
|
{ |
|
59
|
8 |
|
$this->gridFile->fseek(0); |
|
60
|
8 |
|
$rawData = $this->gridFile->fread(52); |
|
61
|
8 |
|
$data = unpack('Gstartbuffer/Exlatsw/Exlonsw/Edlat/Edlon/Nnlat/Nnlon/Nikind/Gendbuffer/', $rawData); |
|
62
|
|
|
|
|
63
|
8 |
|
return $data; |
|
64
|
|
|
} |
|
65
|
|
|
|
|
66
|
8 |
|
public function getValues(float $x, float $y): array |
|
67
|
|
|
{ |
|
68
|
8 |
|
if ($x < 0) { |
|
69
|
8 |
|
$x += 360; // NADCON5 uses 0 = 360 = Greenwich |
|
70
|
|
|
} |
|
71
|
|
|
|
|
72
|
8 |
|
return $this->interpolate($x, $y); |
|
73
|
|
|
} |
|
74
|
|
|
} |
|
75
|
|
|
|
dvdoug /
PHPCoord
