geo/tcSrtmCache.h

   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 #ifndef _tcSrtmCache_h_
  21 #define _tcSrtmCache_h_
  22
  23 /**
  24  * @file tcSrtmCache.h
  25  * @brief Manages cache of SRTM data.
  26  */
  27
  28 #include <QString>
  29 #include <QStringList>
  30 #include <QDir>
  31
  32 class tcSrtmData;
  33 class tcGeo;
  34
  35 /** Manages cache of SRTM data.
  36  * Obtains SRTM elevation data blocks, downloading from nasa if necessary.
  37  *
  38  * FTP site: ftp://e0srp01u.ecs.nasa.gov/
  39  */
  40 class tcSrtmCache
  41 {
  42   public:
  43
  44     /*
  45      * Static functions
  46      */
  47
  48     /// Get a list of datasets.
  49     static QStringList dataSets();
  50
  51     /*
  52      * Constructors + destructor
  53      */
  54
  55     /// Primary constructor.
  56     tcSrtmCache(const QString& dataSet);
  57
  58     /// Destructor.
  59     virtual ~tcSrtmCache();
  60
  61     /*
  62      * Main interface
  63      */
  64
  65     /** Load raw SRTM height file.
  66      * Download the file if necessary.
  67      * @param lon Longitude in degrees.
  68      * @param lat Latitude in degrees.
  69      * @returns SRTM data for the chunk containing (@p lon, @p lat) or 0.
  70      */
  71     tcSrtmData* loadData(int lon, int lat);
  72
  73     /** Load raw SRTM height file.
  74      * Download the file if necessary.
  75      * @param coord Geographical coordinate.
  76      * @returns SRTM data for the chunk containing (@p lon, @p lat) or 0.
  77      */
  78     tcSrtmData* loadData(const tcGeo& coord);
  79
  80     /** Find some SRTM height data overlapping an area.
  81      * @param swCorner Geographical coordinate of south-west corner.
  82      * @param neCorner Geographical coordinate of north-east corner.
  83      * @returns An arbitrary SRTM data for a chunk in the lon lat range.
  84      */
  85     tcSrtmData* findData(const tcGeo& swCorner, const tcGeo& neCorner);
  86
  87   private:
  88
  89     /*
  90      * Private functions
  91      */
  92
  93     /// Convert a geographical coordinate into lon lat ints.
  94     void toIntLonLat(const tcGeo& coord, int* const outLon, int* const outLat);
  95
  96     /// Cache index.
  97     tcSrtmData*& cache(int lon, int lat);
  98
  99   private:
 100
 101     /*
 102      * Static variables
 103      */
 104
 105     /// Directory containing elevation data sets.
 106     static QDir s_dataDirectory;
 107
 108     /*
 109      * Variables
 110      */
 111
 112     /// Dataset name.
 113     QString m_dataSet;
 114
 115     /// Cache of data at each grid point.
 116     tcSrtmData* m_cache[360][180];
 117 };
 118
 119 #endif
 120