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terragear/src/Lib/HGT/hgt.cxx
Ralf Gerlich fcb9e6c8ba Fixed the build system
2007-11-08 22:14:02 +01:00

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8.5 KiB
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// hgt.hxx -- SRTM "hgt" data management class
//
// Written by Curtis Olson, started February 2003.
//
// Copyright (C) 2003 Curtis L. Olson - http://www.flightgear.org/~curt
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// $Id: hgt.cxx,v 1.7 2005-12-19 16:06:45 curt Exp $
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <simgear/compiler.h>
#include <stdlib.h> // atof()
#ifdef SG_HAVE_STD_INCLUDES
# include <cerrno>
#else
# include <errno.h>
#endif
#include <simgear/constants.h>
#include <simgear/io/lowlevel.hxx>
#ifdef _MSC_VER
# include <win32/mkdir.hpp>
#endif
#include "hgt.hxx"
SG_USING_STD(cout);
SG_USING_STD(endl);
TGHgt::TGHgt( int _res ) {
hgt_resolution = _res;
data = new short int[MAX_HGT_SIZE][MAX_HGT_SIZE];
output_data = new short int[MAX_HGT_SIZE][MAX_HGT_SIZE];
remove_tmp_file = false;
}
TGHgt::TGHgt( int _res, const SGPath &file ) {
hgt_resolution = _res;
data = new short int[MAX_HGT_SIZE][MAX_HGT_SIZE];
output_data = new short int[MAX_HGT_SIZE][MAX_HGT_SIZE];
remove_tmp_file = false;
TGHgt::open( file );
}
// open an HGT file
bool
TGHgt::open ( const SGPath &f ) {
SGPath file_name = f;
// open input file (or read from stdin)
if ( file_name.str() == "-" ) {
cout << "Loading HGT data file: stdin" << endl;
if ( (fd = gzdopen(STDIN_FILENO, "r")) == NULL ) {
cout << "ERROR: opening stdin" << endl;
return false;
}
} else {
if ( file_name.extension() == "zip" ) {
// extract the .zip file to /tmp and point the file name
// to the extracted file
cout << "Extracting " << file_name.str() << " to /tmp" << endl;
string command = "unzip -d /tmp " + file_name.base();
system( command.c_str() );
SGPath full_name = file_name.base();
file_name.set( "/tmp" );
if ( full_name.file().empty() ) {
file_name.append( full_name.str() );
} else {
file_name.append( full_name.file() );
}
remove_tmp_file = true;
remove_file_name = file_name.str();
cout << "Proceeding with " << file_name.str() << endl;
}
cout << "Loading HGT data file: " << file_name.str() << endl;
if ( (fd = gzopen( file_name.c_str(), "rb" )) == NULL ) {
SGPath file_name_gz = file_name;
file_name_gz.append( ".gz" );
if ( (fd = gzopen( file_name_gz.c_str(), "rb" )) == NULL ) {
cout << "ERROR: opening " << file_name.str() << " or "
<< file_name_gz.str() << "for reading!" << endl;
return false;
}
}
}
// Determine originx/originy from file name
string name = file_name.file();
cout << " Name = " << name << endl;
originy = atof( name.substr(1, 2).c_str() ) * 3600.0;
if ( name.substr(0, 1) == "S" ) {
originy = -originy;
}
originx = atof( name.substr(4, 3).c_str() ) * 3600.0;
if ( name.substr(3, 1) == "W" ) {
originx = -originx;
}
cout << " Origin = " << originx << ", " << originy << endl;
return true;
}
// close an HGT file
bool
TGHgt::close () {
gzclose(fd);
if ( remove_tmp_file ) {
string command = "/bin/rm " + remove_file_name;
system( command.c_str() );
}
return true;
}
// load an hgt file
bool
TGHgt::load( ) {
int size;
if ( hgt_resolution == 1 ) {
cols = rows = size = 3601;
col_step = row_step = 1;
} else if ( hgt_resolution == 3 ) {
cols = rows = size = 1201;
col_step = row_step = 3;
} else {
cout << "Unknown HGT resolution, only 1 and 3 arcsec formats" << endl;
cout << " are supported!" << endl;
return false;
}
short int *var;
for ( int row = size - 1; row >= 0; --row ) {
for ( int col = 0; col < size; ++col ) {
var = &data[col][row];
if ( gzread ( fd, var, sizeof(short) ) != sizeof(short) ) {
return false;
}
if ( sgIsLittleEndian() ) {
sgEndianSwap( (unsigned short int*)var);
}
}
}
return true;
}
// write out the area of data covered by the specified bucket. Data
// is written out column by column starting at the lower left hand
// corner.
bool
TGHgt::write_area( const string& root, SGBucket& b ) {
// calculate some boundaries
double min_x = ( b.get_center_lon() - 0.5 * b.get_width() ) * 3600.0;
double max_x = ( b.get_center_lon() + 0.5 * b.get_width() ) * 3600.0;
double min_y = ( b.get_center_lat() - 0.5 * b.get_height() ) * 3600.0;
double max_y = ( b.get_center_lat() + 0.5 * b.get_height() ) * 3600.0;
cout << b << endl;
cout << "width = " << b.get_width() << " height = " << b.get_height()
<< endl;
cout << "min = " << min_x << "," << min_y
<< " max = " << max_x << "," << max_y << endl;
int start_x = (int)((min_x - originx) / col_step);
int span_x = (int)(b.get_width() * 3600.0 / col_step);
int start_y = (int)((min_y - originy) / row_step);
int span_y = (int)(b.get_height() * 3600.0 / row_step);
cout << "start_x = " << start_x << " span_x = " << span_x << endl;
cout << "start_y = " << start_y << " span_y = " << span_y << endl;
// Do a simple sanity checking. But, please, please be nice to
// this write_area() routine and feed it buckets that coincide
// well with the underlying grid structure and spacing.
if ( ( min_x < originx )
|| ( max_x > originx + cols * col_step )
|| ( min_y < originy )
|| ( max_y > originy + rows * row_step ) ) {
cout << " ERROR: bucket at least partially outside HGT data range!" <<
endl;
return false;
}
// If the area is all ocean, skip it.
if ( !has_non_zero_elev(start_x, span_x, start_y, span_y) ) {
cout << "Tile is all zero elevation: skipping" << endl;
return false;
}
// generate output file name
string base = b.gen_base_path();
string path = root + "/" + base;
#ifdef _MSC_VER
fg_mkdir( path.c_str() );
#else
string command = "mkdir -p " + path;
system( command.c_str() );
#endif
string array_file = path + "/" + b.gen_index_str() + ".arr.gz";
cout << "array_file = " << array_file << endl;
// write the file
gzFile fp;
if ( (fp = gzopen( array_file.c_str(), "wb9" )) == NULL ) {
cout << "ERROR: cannot open " << array_file << " for writing!" << endl;
exit(-1);
}
gzprintf( fp, "%d %d\n", (int)min_x, (int)min_y );
gzprintf( fp, "%d %d %d %d\n", span_x + 1, (int)col_step,
span_y + 1, (int)row_step );
for ( int i = start_x; i <= start_x + span_x; ++i ) {
for ( int j = start_y; j <= start_y + span_y; ++j ) {
gzprintf( fp, "%d ", (int)data[i][j] );
}
gzprintf( fp, "\n" );
}
gzclose(fp);
return true;
}
// write the entire area out in a simple ascii format
bool TGHgt::write_whole_ascii( const string& file ) {
cout << "writing to " << file << endl;
// write the file
gzFile fp;
if ( (fp = gzopen( file.c_str(), "wb9" )) == NULL ) {
cout << "ERROR: cannot open " << file << " for writing!" << endl;
exit(-1);
}
gzprintf( fp, "%d\n%d\n", rows, cols );
for ( int row = rows - 1; row >= 0; row-- ) {
for ( int col = 0; col < cols; col++ ) {
gzprintf( fp, "%d\n", (int)data[col][row] );
}
}
gzclose(fp);
return true;
}
TGHgt::~TGHgt() {
// printf("class TGHgt DEstructor called.\n");
delete [] data;
delete [] output_data;
}
bool
TGHgt::has_non_zero_elev (int start_x, int span_x,
int start_y, int span_y) const
{
for ( int row = start_y; row < start_y + span_y; row++ ) {
for ( int col = start_x; col < start_x + span_x; col++ ) {
if ( data[col][row] != 0 )
return true;
}
}
return false;
}
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