Add provider for SRTM 1-arc second files (#3)

* add srtm 1-arc second provider * fix srtm 1-arc second provider for multiple rows per strip * fix code style * remove hhvm from travis build matrix * add srtm 1-arc second test files
Runalyze · Jun 9, 2017 · acc7a48 · acc7a48
1 parent 3574b98
commit acc7a48
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Showing 5 changed files with 270 additions and 11 deletions.
diff --git a/.travis.yml b/.travis.yml
@@ -4,7 +4,6 @@ php:
   - 5.5
   - 5.6
   - 7.0
-  - hhvm
 
 sudo: false
 

diff --git a/bin/download-testfiles.sh b/bin/download-testfiles.sh
@@ -11,4 +11,12 @@ do
         unzip -o tests/testfiles/${file}.zip ${file}.tif -d tests/testfiles
         rm -rf tests/testfiles/${file}.zip
     fi
+done
+
+for file in n40_w075 n49_e007 n51_w001 s23_e017 s34_e151
+do
+    if [ ! -f tests/testfiles/${file}_1arc_v3.tif ]
+    then
+        curl https://cdn.runalyze.com/static/srtm1/${file}_1arc_v3.tif > tests/testfiles/${file}_1arc_v3.tif
+    fi
 done
diff --git a/src/Provider/GeoTIFF/GeoTIFFReader.php b/src/Provider/GeoTIFF/GeoTIFFReader.php
@@ -14,6 +14,9 @@
 use Runalyze\DEM\Exception\RuntimeException;
 use Runalyze\DEM\Provider\AbstractResourceReader;
 
+/**
+ * @see http://www.awaresystems.be/imaging/tiff/tifftags.html
+ */
 class GeoTIFFReader extends AbstractResourceReader
 {
     /**
@@ -22,13 +25,6 @@ class GeoTIFFReader extends AbstractResourceReader
      */
     const LEN_OFFSET = 4;
 
-    /**
-     * The number of bytes containing each item of elevation data
-     * (= BitsPerSample tag value / 8).
-     * @var int
-     */
-    const BYTES_PER_SAMPLE = 2;
-
     /**
      * Magic number located at bytes 2-3 which identifies a TIFF file.
      * @var int
@@ -44,6 +40,15 @@ class GeoTIFFReader extends AbstractResourceReader
     /** @var int */
     const TIFF_CONST_IMAGE_LENGTH = 257;
 
+    /** @var int */
+    const TIFF_CONST_BITS_PER_SAMPLE = 258;
+
+    /** @var int */
+    const TIFF_CONST_SAMPLES_PER_PIXEL = 277;
+
+    /** @var int */
+    const TIFF_CONST_ROWS_PER_STRIP = 278;
+
     /** @var int */
     const TIFF_CONST_STRIPBYTECOUNTS = 279;
 
@@ -59,6 +64,15 @@ class GeoTIFFReader extends AbstractResourceReader
     /** @var int */
     const UNKNOWN = -32768;
 
+    /** @var int The number of bytes containing each item of elevation data */
+    protected $BytesPerSample = 2;
+
+    /** @var int 	The number of components per pixel */
+    protected $SamplesPerPixel = 1;
+
+    /** @var int The number of rows per strip */
+    protected $RowsPerStrip = 1;
+
     /** @var int */
     protected $NumDataRows;
 
@@ -130,6 +144,15 @@ protected function readIFDEntries()
                 case static::TIFF_CONST_IMAGE_LENGTH:
                     $this->NumDataRows = $constData['offset'];
                     break;
+                case static::TIFF_CONST_BITS_PER_SAMPLE:
+                    $this->BytesPerSample = (int) ($constData['offset'] / 8);
+                    break;
+                case static::TIFF_CONST_SAMPLES_PER_PIXEL:
+                    $this->SamplesPerPixel = $constData['offset'];
+                    break;
+                case static::TIFF_CONST_ROWS_PER_STRIP:
+                    $this->RowsPerStrip = $constData['offset'];
+                    break;
                 case static::TIFF_CONST_STRIPOFSETS:
                     $this->StripOffsets = $constData['offset'];
                     break;
@@ -165,13 +188,13 @@ public function getExactRowAndColFor($relativeLatitude, $relativeLongitude)
      */
     public function getElevationFor($row, $col)
     {
-        fseek($this->FileResource, $this->StripOffsets + ($row * static::LEN_OFFSET));
+        fseek($this->FileResource, $this->StripOffsets + ceil($row / $this->RowsPerStrip) * static::LEN_OFFSET);
 
         $firstColumnData = unpack('Voffset', fread($this->FileResource, static::LEN_OFFSET));
 
-        fseek($this->FileResource, $firstColumnData['offset'] + $col * static::BYTES_PER_SAMPLE);
+        fseek($this->FileResource, $firstColumnData['offset'] + ($this->NumDataCols * ($row % $this->RowsPerStrip) + $col) * $this->BytesPerSample);
 
-        $elevation = unpack('velevation', fread($this->FileResource, static::BYTES_PER_SAMPLE))['elevation'];
+        $elevation = unpack('velevation', fread($this->FileResource, $this->BytesPerSample))['elevation'];
 
         return ($elevation <= self::UNKNOWN || $elevation >= -self::UNKNOWN) ? false : $elevation;
     }

diff --git a/src/Provider/GeoTIFF/SRTM1ArcSecondProvider.php b/src/Provider/GeoTIFF/SRTM1ArcSecondProvider.php
@@ -0,0 +1,68 @@
+<?php
+
+/*
+ * This file is part of the Runalyze DEM Reader.
+ *
+ * (c) RUNALYZE <[email protected]>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace Runalyze\DEM\Provider\GeoTIFF;
+
+use Runalyze\DEM\Exception\InvalidArgumentException;
+
+class SRTM1ArcSecondProvider extends SRTM4Provider
+{
+    /** @var float */
+    const DEGREES_PER_TILE = 1.0;
+
+    /** @var string */
+    protected $FilenameFormat = '%s%02d_%s%03d.tif';
+
+    /**
+     * @param  float                    $latitude
+     * @param  float                    $longitude
+     * @return string
+     * @throws InvalidArgumentException
+     */
+    protected function getFilenameFor($latitude, $longitude)
+    {
+        $this->loadTileReferencesFor($latitude, $longitude);
+
+        return sprintf(
+            $this->FilenameFormat,
+            $this->CurrentTileVerticalReference < 0 ? 's' : 'n',
+            abs($this->CurrentTileVerticalReference),
+            $this->CurrentTileHorizontalReference < 0 ? 'w' : 'e',
+            abs($this->CurrentTileHorizontalReference)
+        );
+    }
+
+    /**
+     * @param float $latitude
+     * @param float $longitude
+     */
+    protected function loadTileReferencesFor($latitude, $longitude)
+    {
+        $this->CurrentTileVerticalReference = floor($latitude / static::DEGREES_PER_TILE);
+        $this->CurrentTileHorizontalReference = floor($longitude / static::DEGREES_PER_TILE);
+
+        $this->CurrentTileLatitude = $this->CurrentTileVerticalReference;
+        $this->CurrentTileLongitude = $this->CurrentTileHorizontalReference;
+    }
+
+    /**
+     * @param  float   $latitude
+     * @param  float   $longitude
+     * @return float[] array(row, col)
+     */
+    protected function getExactRowAndColFor($latitude, $longitude)
+    {
+        return $this->ResourceReader->getExactRowAndColFor(
+            abs($this->CurrentTileLatitude + 1 - $latitude) / static::DEGREES_PER_TILE,
+            abs($longitude - $this->CurrentTileLongitude) / static::DEGREES_PER_TILE
+        );
+    }
+}
diff --git a/src/Tests/Provider/GeoTIFF/SRTM1ArcSecondProviderTest.php b/src/Tests/Provider/GeoTIFF/SRTM1ArcSecondProviderTest.php
@@ -0,0 +1,161 @@
+<?php
+
+/*
+ * This file is part of the Runalyze DEM Reader.
+ *
+ * (c) RUNALYZE <[email protected]>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace Runalyze\DEM\Tests\Provider\GeoTIFF;
+
+use Runalyze\DEM\Interpolation\BilinearInterpolation;
+use Runalyze\DEM\Provider\GeoTIFF\SRTM1ArcSecondProvider;
+
+class SRTM1ArcSecondProviderTest extends \PHPUnit_Framework_TestCase
+{
+    /** @var string */
+    const PATH_TO_FILES = '/../../../../tests/testfiles';
+
+    /**
+     * @var SRTM1ArcSecondProvider
+     */
+    protected $Provider;
+
+    public function setUp()
+    {
+        $this->Provider = new SRTM1ArcSecondProvider(__DIR__.self::PATH_TO_FILES);
+        $this->Provider->setFilenameFormat('%s%02d_%s%03d_1arc_v3.tif');
+        $this->Provider->setInterpolation(new BilinearInterpolation());
+    }
+
+    /**
+     * @param string $filename
+     */
+    protected function checkFile($filename)
+    {
+        if (!$this->fileIsThere($filename)) {
+            $this->markTestSkipped('Required testfile "'.$filename.'" is not available.');
+        }
+    }
+
+    /**
+     * @param  string $filename
+     * @return bool
+     */
+    protected function fileIsThere($filename)
+    {
+        return file_exists(__DIR__.self::PATH_TO_FILES.'/'.$filename);
+    }
+
+    public function testTileBoundary()
+    {
+        $this->checkFile('n49_e007_1arc_v3.tif');
+
+        if (
+            !$this->fileIsThere('n49_e006_1arc_v3.tif') &&
+            !$this->fileIsThere('n49_e008_1arc_v3.tif') &&
+            !$this->fileIsThere('n48_e007_1arc_v3.tif') &&
+            !$this->fileIsThere('n50_e007_1arc_v3.tif')
+        ) {
+            $this->assertTrue($this->Provider->hasDataFor([[49.00000, 7.00000]]));
+            $this->assertTrue($this->Provider->hasDataFor([[49.99999, 7.00000]]));
+            $this->assertTrue($this->Provider->hasDataFor([[49.99999, 7.99999]]));
+            $this->assertTrue($this->Provider->hasDataFor([[49.00000, 7.99999]]));
+
+            $this->assertFalse($this->Provider->hasDataFor([[49.00000, 6.99999]]));
+            $this->assertFalse($this->Provider->hasDataFor([[49.00000, 8.00000]]));
+            $this->assertFalse($this->Provider->hasDataFor([[48.99999, 7.99999]]));
+        } else {
+            $this->markTestSkipped('Can\'t check boundaries of tile as too many files are there.');
+        }
+    }
+
+    /**
+     * @group germany
+     */
+    public function testSingleElevationInGermany()
+    {
+        $this->checkFile('n49_e007_1arc_v3.tif');
+
+        // SRTM4: 237
+        $this->assertEquals(239, $this->Provider->getElevation(49.444722, 7.768889));
+    }
+
+    public function testMultipleElevationsInSydney()
+    {
+        $this->checkFile('s34_e151_1arc_v3.tif');
+
+        // SRTM4: 4, 4, 3
+        $this->assertEquals(
+            [3, 3, 2],
+            $this->Provider->getElevations(
+                [-33.8706555, -33.8705667, -33.8704860],
+                [151.1486918, 151.1486337, 151.1485585]
+            )
+        );
+    }
+
+    /**
+     * @group london
+     */
+    public function testLocationsInLondon()
+    {
+        $this->checkFile('n51_w001_1arc_v3.tif');
+
+        // SRTM4: 20, 19, 19
+        $this->assertEquals(
+            [18, 19, 18],
+            $this->Provider->getElevations(
+                [51.5073509, 51.5074509, 51.5075509],
+                [-0.1277583, -0.1278583, -0.1279583]
+            )
+        );
+    }
+
+    public function testLocationsInWindhoek()
+    {
+        $this->checkFile('s23_e017_1arc_v3.tif');
+
+        // SRTM4: 1668, 1671, 1672
+        $this->assertEquals(
+            [1665, 1672, 1671],
+            $this->Provider->getElevations(
+                [-22.5700, -22.5705, -22.5710],
+                [17.0836,  17.0841,  17.0846]
+            )
+        );
+    }
+
+    public function testNewYork()
+    {
+        $this->checkFile('n40_w075_1arc_v3.tif');
+
+        // SRTM4: 26, 29, 39
+        $this->assertEquals(
+            [28, 27, 46],
+            $this->Provider->getElevations(
+                [40.7127,  40.7132,  40.7137],
+                [-74.0059, -74.0064, -74.0069]
+            )
+        );
+    }
+
+    public function testNewYorkWithoutInterpolation()
+    {
+        $this->checkFile('n40_w075_1arc_v3.tif');
+
+        $this->Provider->removeInterpolation();
+
+        // SRTM4: 26, 32, 32
+        $this->assertEquals(
+            [28, 28, 48],
+            $this->Provider->getElevations(
+                [40.7127,  40.7132,  40.7137],
+                [-74.0059, -74.0064, -74.0069]
+            )
+        );
+    }
+}
-Original file line number
+Diff line change
@@ Expand Up / @@ -4,7 +4,6 @@ php: @@
       - 5.5
       - 5.6
       - 7.0
-      - hhvm
     sudo: false
@@ Expand Down @@