geo/tcSrtmData.cpp

   1 /***************************************************************************
   2  *   This file is part of Tecorrec.                                        *
   3  *   Copyright 2008 James Hogan <james@albanarts.com>                      *
   4  *                                                                         *
   5  *   Tecorrec is free software: you can redistribute it and/or modify      *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation, either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   Tecorrec is distributed in the hope that it will be useful,           *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU General Public License     *
  16  *   along with Tecorrec.  If not, write to the Free Software Foundation,  *
  17  *   Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.   *
  18  ***************************************************************************/
  19
  20 /**
  21  * @file tcSrtmData.cpp
  22  * @brief Block of raw SRTM elevation data.
  23  */
  24
  25 #include "tcSrtmData.h"
  26
  27 #include <QFile>
  28 #include <QDataStream>
  29
  30 #include <cmath>
  31
  32 /*
  33  * Constructors + destructor
  34  */
  35
  36 /// Load SRTM data.
  37 tcSrtmData::tcSrtmData(int lon, int lat, const QString& filename)
  38 : m_lon(lon)
  39 , m_lat(lat)
  40 {
  41   QFile file(filename);
  42   if (!file.open(QIODevice::ReadOnly))
  43   {
  44     return;
  45   }
  46
  47   QDataStream in(&file);
  48   in.setByteOrder(QDataStream::BigEndian);
  49   for (int i = 0; i < 1201; ++i)
  50   {
  51     for (int j = 0; j < 1201; ++j)
  52     {
  53       Q_ASSERT(!in.atEnd());
  54       in >> m_data[i][j];
  55     }
  56   }
  57   Q_ASSERT(in.atEnd());
  58 }
  59
  60 /// Destructor.
  61 tcSrtmData::~tcSrtmData()
  62 {
  63 }
  64
  65 /*
  66  * Accessors
  67  */
  68
  69 /// Get the longitude in degrees.
  70 int tcSrtmData::lon() const
  71 {
  72   return m_lon;
  73 }
  74
  75 /// Get the latitude in degrees.
  76 int tcSrtmData::lat() const
  77 {
  78   return m_lat;
  79 }
  80
  81 /// Get the number of scan lines.
  82 int tcSrtmData::lines() const
  83 {
  84   return 1201;
  85 }
  86
  87 /// Get the length of each scan line.
  88 int tcSrtmData::length() const
  89 {
  90   return 1201;
  91 }
  92
  93 /// Get the geographical coordinate of a pixel.
  94 tcGeo tcSrtmData::pixelCoordinate(int line, int pixel) const
  95 {
  96   return tcGeo(M_PI/180*((double)m_lon + (double)pixel/length()),
  97                M_PI/180*((double)(m_lat+1) - (double)line /lines() ));
  98 }
  99
 100 /// Get the altitude at a pixel.
 101 uint32_t tcSrtmData::pixelAltitude(int line, int pixel) const
 102 {
 103   return m_data[line][pixel];
 104 }