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Refactored access to NASA data

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This commit is contained in:
DennisOSRM 2011-12-31 15:59:37 +01:00
parent 53d87eb9be
commit 1741ce7ec9
3 changed files with 263 additions and 0 deletions
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106
Util/NASAGridSquare.cpp Normal file
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/*
open source routing machine
Copyright (C) Dennis Luxen, others 2010
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU AFFERO General Public License as published by
the Free Software Foundation; either version 3 of the License, or
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 Affero General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
or see http://www.gnu.org/licenses/agpl.txt.
*/
#include "NASAGridSquare.h"
NasaGridSquare::~NasaGridSquare() {
DELETE(elevationMap);
}
std::string NasaGridSquare::make_filename(const char* ext) const {
char EW =(longitude>=0 ? 'E' : 'W' );
char NS =(latitude >=0 ? 'N' : 'S');
std::stringstream ss;
ss<<setfill('0')
<< ROOT_PATH
<< "/"
<<NS
<<setw(2)<<abs(latitude)<<setw(0)
<<EW
<<setw(3)<<abs(longitude)<<setw(0)
<<'.'<<ext;
return ss.str();
}
void NasaGridSquare::load(const char* filename) {
const std::string gzipfile =std::string(filename)+".zip";
std::cout << "testing for zipped file " << gzipfile << std::endl;
if(exists(gzipfile.c_str())) {
std::cout << gzipfile << " exists" << std::endl;
}
int errorcode = 0;
int errorcode2 = 0;
zip * test = zip_open(gzipfile.c_str(), 0, &errorcode);
if(errorcode) {
char buffer[1024];
zip_error_to_str(buffer, 1024, errorcode, errno);
ERR("Error occured opening zipfile " << filename << ", error: " << buffer);
//TODO: Load from URL
return;
}
unsigned entries = zip_get_num_files(test);
INFO("File has " << entries << " entries");
struct zip_stat stat;
zip_stat_index(test, 0, 0, &stat);
INFO("included: " << stat.name);
INFO("uncompressed: " << stat.size);
INFO("compressed: " << stat.comp_size);
num_bytes = stat.size;
DELETE(elevationMap);
elevationMap = new char[stat.size];
zip_file * file = zip_fopen_index(test, 0, 0 );
zip_file_error_get(file, &errorcode, &errorcode2);
zip_fread(file, elevationMap, stat.size);
zip_fclose(file);
zip_close(test);
}
bool NasaGridSquare::lngLat_to_colRow(float lng_fraction, float lat_fraction, unsigned int& col, unsigned int& row) const {
col = int( 0.5 + lng_fraction * float(numCols-1) );
row = numRows-1 - int( 0.5 + lat_fraction * float(numRows-1) );
return( col<numCols && row<numRows );
}
NasaGridSquare::NasaGridSquare(int lng, int lat, std::string & _rp) : ROOT_PATH(_rp), elevationMap(NULL), longitude(lng), latitude(lat), num_bytes(0), numRows(1), numCols(1) {
std::string filename =make_filename("hgt");
std::cout << "Loading " << filename << std::endl;
load(filename.c_str());
if(hasData())
numRows=numCols=std::sqrt(num_bytes/2);
}
short NasaGridSquare::getHeight(float lng_fraction, float lat_fraction) const {
if(!hasData())
return NO_DATA;
unsigned int col,row;
if(!lngLat_to_colRow(lng_fraction,lat_fraction, col,row))
return NO_DATA;
if(col>=numCols || row>=numRows)
return NO_DATA;
unsigned int i=( col + row * numCols );
unsigned short datum2=((unsigned short*)elevationMap)[i];
short result2=(datum2>>8 | datum2<<8);
return result2;
}

70
Util/NASAGridSquare.h Normal file
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/*
open source routing machine
Copyright (C) Dennis Luxen, others 2010
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU AFFERO General Public License as published by
the Free Software Foundation; either version 3 of the License, or
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 Affero General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
or see http://www.gnu.org/licenses/agpl.txt.
*/
#ifndef NASA_GRID_SQUARE_H
#define NASA_GRID_SQUARE_H
#include "ProjectionUtils.h"
#include "../typedefs.h"
#include <cmath>
#include <string>
#include <sstream>
#include <cstdio>
#include <cstring>
#include <fstream>
#include <iostream>
#include <zip.h>
class NasaGridSquare {
public:
const static short NO_DATA =-32768; ///< NASA's magic number for no data.
NasaGridSquare(int lng, int lat, std::string & _rp);
~NasaGridSquare();
short getHeight(float lng_fraction, float lat_fraction) const;
bool hasData() const {return bool(elevationMap != NULL);}
private:
std::string ROOT_PATH;
char * elevationMap;
int longitude;
int latitude;
unsigned int num_bytes; ///< Length of data.
unsigned int numRows;
unsigned int numCols;
std::string make_filename(const char* ext) const;
/** Loads the file into memory, pointed to by 'data'. Sets num_bytes. */
void load(const char* filename);
/** Converts lng,lat floats to col,row ints. Returns TRUE if result valid. */
bool lngLat_to_colRow(float lng_fraction, float lat_fraction, unsigned int& col, unsigned int& row) const;
inline bool exists(const char* path) {
std::ifstream ifile(path);
return ifile;
}
};
#endif // NASA_GRID_SQUARE_H

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/*
open source routing machine
Copyright (C) Dennis Luxen, others 2010
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU AFFERO General Public License as published by
the Free Software Foundation; either version 3 of the License, or
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 Affero General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
or see http://www.gnu.org/licenses/agpl.txt.
** Interface to the GridSquares. Template parameter determines which kind of
* raw data is used (NASA, or reduced). GridSquare data is globally cached, so
* that many queries can be answered without having to constantly mmap & unmmap
* the data files.
*
* Typical usage:
*
* Grid<NasaGridSquare> g();
* cout << g.height(lng,lat) << endl;
*
*/
#ifndef SRTMLOOKUP_H
#define SRTMLOOKUP_H
#include <cassert>
#include <string>
#include "NASAGridSquare.h"
#include "../DataStructures/LRUCache.h"
class SRTMLookup {
public:
SRTMLookup(std::string & _rp) : cache(MAX_CACHE_SIZE), ROOT_PATH(_rp) {
// Double check that this compiler truncates towards zero.
assert(-1 == int(float(-1.9)));
}
/** Returns the height above sea level for the given lat/lng. */
short height(const float longitude, const float latitude) {
if(0 == ROOT_PATH.size())
return 0;
int lng,lat;
float lng_fraction,lat_fraction;
split(longitude,lng,lng_fraction);
split(latitude ,lat,lat_fraction);
int k = key(lng,lat);
if(!cache.Holds(k)) {
cache.Insert(k , new NasaGridSquare(lng,lat, ROOT_PATH));
}
NasaGridSquare * result;
cache.Fetch(k, result);
return result->getHeight(lng_fraction,lat_fraction);
}
private:
/** Split a floating point number (num) into integer (i) & fraction (f)
* components. */
inline void split(float num, int& i, float& f) const {
if(num>=0.0)
i=int(num);
else
i=int(num)-1;
f=num-float(i);
}
/** Formula for grid squares' unique keys. */
int key(int lng, int lat) {
return 1000*lat + lng;
}
LRUCache<NasaGridSquare*> cache;
static const int MAX_CACHE_SIZE = 250;
std::string ROOT_PATH;
};
#endif // SRTMLOOKUP_H