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flightgear/Array/array.cxx
curt c6f97e5413 More sensible handling of the case where no dem file for this tile exists 
(or has been generated).
1999-03-27 14:05:10 +00:00

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// array.cxx -- Array management class
//
// Written by Curtis Olson, started March 1998.
//
// Copyright (C) 1998 - 1999 Curtis L. Olson - curt@flightgear.org
//
// 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.
//
// $Id$
// (Log is kept at end of this file)
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <Include/compiler.h>
// #include <ctype.h> // isspace()
// #include <stdlib.h> // atoi()
// #include <math.h> // rint()
// #include <stdio.h>
// #include <string.h>
// #ifdef HAVE_SYS_STAT_H
// # include <sys/stat.h> // stat()
// #endif
// #ifdef FG_HAVE_STD_INCLUDES
// # include <cerrno>
// #else
// # include <errno.h>
// #endif
// #ifdef HAVE_UNISTD_H
// # include <unistd.h> // stat()
// #endif
#include STL_STRING
#include <Include/fg_constants.h>
#include <Misc/fgstream.hxx>
#include <Misc/strutils.hxx>
#include <Math/leastsqs.hxx>
#include "array.hxx"
FG_USING_STD(string);
FGArray::FGArray( void ) {
// cout << "class FGArray CONstructor called." << endl;
in_data = new float[ARRAY_SIZE_1][ARRAY_SIZE_1];
// out_data = new float[ARRAY_SIZE_1][ARRAY_SIZE_1];
}
FGArray::FGArray( const string &file ) {
// cout << "class FGArray CONstructor called." << endl;
in_data = new float[ARRAY_SIZE_1][ARRAY_SIZE_1];
// out_data = new float[ARRAY_SIZE_1][ARRAY_SIZE_1];
FGArray::open(file);
}
// open an Array file
int
FGArray::open( const string& file ) {
// open input file (or read from stdin)
if ( file == "-" ) {
cout << " Opening array data pipe from stdin" << endl;
// fd = stdin;
// fd = gzdopen(STDIN_FILENO, "r");
cout << " Not yet ported ..." << endl;
return 0;
} else {
in = new fg_gzifstream( file );
if ( ! in->is_open() ) {
cout << " Cannot open " << file << endl;
return 0;
}
cout << " Opening array data file: " << file << endl;
}
return 1;
}
// close an Array file
int
FGArray::close() {
// the fg_gzifstream doesn't seem to have a close()
delete in;
return 1;
}
// parse Array file
int
FGArray::parse() {
*in >> originx >> originy;
*in >> cols >> col_step;
*in >> rows >> row_step;
cout << " origin = " << originx << " " << originy << endl;
cout << " cols = " << cols << " rows = " << rows << endl;
cout << " col_step = " << col_step << " row_step = " << row_step <<endl;
for ( int i = 0; i < cols; i++ ) {
for ( int j = 0; j < rows; j++ ) {
*in >> in_data[i][j];
}
}
cout << " Done parsing\n";
return 1;
}
// add a node to the output corner node list
void FGArray::add_corner_node( int i, int j, double val ) {
double x = (originx + i * col_step) / 3600.0;
double y = (originy + j * row_step) / 3600.0;
// cout << Point3D(x, y, val) << endl;
corner_list.push_back( Point3D(x, y, val) );
}
// add a node to the output fitted node list
void FGArray::add_fit_node( int i, int j, double val ) {
double x = (originx + i * col_step) / 3600.0;
double y = (originy + j * row_step) / 3600.0;
// cout << Point3D(x, y, val) << endl;
node_list.push_back( Point3D(x, y, val) );
}
// Use least squares to fit a simpler data set to dem data
void FGArray::fit( double error ) {
double x[ARRAY_SIZE_1], y[ARRAY_SIZE_1];
double m, b, max_error, error_sq;
double x1, y1;
// double ave_error;
double cury, lasty;
int n, row, start, end;
int colmin, colmax, rowmin, rowmax;
bool good_fit;
// FILE *dem, *fit, *fit1;
error_sq = error * error;
cout << " Initializing output mesh structure" << endl;
// outputmesh_init();
// determine dimensions
colmin = 0;
colmax = cols;
rowmin = 0;
rowmax = rows;
cout << " Fitting region = " << colmin << "," << rowmin << " to "
<< colmax << "," << rowmax << endl;;
// generate corners list
add_corner_node( colmin, rowmin, in_data[colmin][rowmin] );
add_corner_node( colmin, rowmax-1, in_data[colmin][rowmax] );
add_corner_node( colmax-1, rowmin, in_data[colmax][rowmin] );
add_corner_node( colmax-1, rowmax-1, in_data[colmax][rowmax] );
cout << " Beginning best fit procedure" << endl;
lasty = 0;
for ( row = rowmin; row < rowmax; row++ ) {
// fit = fopen("fit.dat", "w");
// fit1 = fopen("fit1.dat", "w");
start = colmin;
// cout << " fitting row = " << row << endl;
while ( start < colmax - 1 ) {
end = start + 1;
good_fit = true;
x[0] = start * col_step;
y[0] = in_data[start][row];
x[1] = end * col_step;
y[1] = in_data[end][row];
n = 2;
// cout << "Least square of first 2 points" << endl;
least_squares(x, y, n, &m, &b);
end++;
while ( (end < colmax) && good_fit ) {
++n;
// cout << "Least square of first " << n << " points" << endl;
x[n-1] = x1 = end * col_step;
y[n-1] = y1 = in_data[end][row];
least_squares_update(x1, y1, &m, &b);
// ave_error = least_squares_error(x, y, n, m, b);
max_error = least_squares_max_error(x, y, n, m, b);
/*
printf("%d - %d ave error = %.2f max error = %.2f y = %.2f*x + %.2f\n",
start, end, ave_error, max_error, m, b);
f = fopen("gnuplot.dat", "w");
for ( j = 0; j <= end; j++) {
fprintf(f, "%.2f %.2f\n", 0.0 + ( j * col_step ),
in_data[row][j]);
}
for ( j = start; j <= end; j++) {
fprintf(f, "%.2f %.2f\n", 0.0 + ( j * col_step ),
in_data[row][j]);
}
fclose(f);
printf("Please hit return: "); gets(junk);
*/
if ( max_error > error_sq ) {
good_fit = false;
}
end++;
}
if ( !good_fit ) {
// error exceeded the threshold, back up
end -= 2; // back "end" up to the last good enough fit
n--; // back "n" up appropriately too
} else {
// we popped out of the above loop while still within
// the error threshold, so we must be at the end of
// the data set
end--;
}
least_squares(x, y, n, &m, &b);
// ave_error = least_squares_error(x, y, n, m, b);
max_error = least_squares_max_error(x, y, n, m, b);
/*
printf("\n");
printf("%d - %d ave error = %.2f max error = %.2f y = %.2f*x + %.2f\n",
start, end, ave_error, max_error, m, b);
printf("\n");
fprintf(fit1, "%.2f %.2f\n", x[0], m * x[0] + b);
fprintf(fit1, "%.2f %.2f\n", x[end-start], m * x[end-start] + b);
*/
if ( start > colmin ) {
// skip this for the first line segment
cury = m * x[0] + b;
add_fit_node( start, row, (lasty + cury) / 2 );
// fprintf(fit, "%.2f %.2f\n", x[0], (lasty + cury) / 2);
}
lasty = m * x[end-start] + b;
start = end;
}
/*
fclose(fit);
fclose(fit1);
dem = fopen("gnuplot.dat", "w");
for ( j = 0; j < ARRAY_SIZE_1; j++) {
fprintf(dem, "%.2f %.2f\n", 0.0 + ( j * col_step ),
in_data[j][row]);
}
fclose(dem);
*/
// NOTICE, this is for testing only. This instance of
// output_nodes should be removed. It should be called only
// once at the end once all the nodes have been generated.
// newmesh_output_nodes(&nm, "mesh.node");
// printf("Please hit return: "); gets(junk);
}
// outputmesh_output_nodes(fg_root, p);
}
// return the current altitude based on grid data. We should rewrite
// this to interpolate exact values, but for now this is good enough
double FGArray::interpolate_altitude( double lon, double lat ) const {
// we expect incoming (lon,lat) to be in arcsec for now
double xlocal, ylocal, dx, dy, zA, zB, elev;
int x1, x2, x3, y1, y2, y3;
float z1, z2, z3;
int xindex, yindex;
/* determine if we are in the lower triangle or the upper triangle
______
| /|
| / |
| / |
|/ |
------
then calculate our end points
*/
xlocal = (lon - originx) / col_step;
ylocal = (lat - originy) / row_step;
xindex = (int)(xlocal);
yindex = (int)(ylocal);
// printf("xindex = %d yindex = %d\n", xindex, yindex);
if ( xindex + 1 == cols ) {
xindex--;
}
if ( yindex + 1 == rows ) {
yindex--;
}
if ( (xindex < 0) || (xindex + 1 >= cols) ||
(yindex < 0) || (yindex + 1 >= rows) ) {
cout << "WARNING: Attempt to interpolate value outside of array!!!"
<< endl;
return 0;
}
dx = xlocal - xindex;
dy = ylocal - yindex;
if ( dx > dy ) {
// lower triangle
// printf(" Lower triangle\n");
x1 = xindex;
y1 = yindex;
z1 = in_data[x1][y1];
x2 = xindex + 1;
y2 = yindex;
z2 = in_data[x2][y2];
x3 = xindex + 1;
y3 = yindex + 1;
z3 = in_data[x3][y3];
// printf(" dx = %.2f dy = %.2f\n", dx, dy);
// printf(" (x1,y1,z1) = (%d,%d,%d)\n", x1, y1, z1);
// printf(" (x2,y2,z2) = (%d,%d,%d)\n", x2, y2, z2);
// printf(" (x3,y3,z3) = (%d,%d,%d)\n", x3, y3, z3);
zA = dx * (z2 - z1) + z1;
zB = dx * (z3 - z1) + z1;
// printf(" zA = %.2f zB = %.2f\n", zA, zB);
if ( dx > FG_EPSILON ) {
elev = dy * (zB - zA) / dx + zA;
} else {
elev = zA;
}
} else {
// upper triangle
// printf(" Upper triangle\n");
x1 = xindex;
y1 = yindex;
z1 = in_data[x1][y1];
x2 = xindex;
y2 = yindex + 1;
z2 = in_data[x2][y2];
x3 = xindex + 1;
y3 = yindex + 1;
z3 = in_data[x3][y3];
// printf(" dx = %.2f dy = %.2f\n", dx, dy);
// printf(" (x1,y1,z1) = (%d,%d,%d)\n", x1, y1, z1);
// printf(" (x2,y2,z2) = (%d,%d,%d)\n", x2, y2, z2);
// printf(" (x3,y3,z3) = (%d,%d,%d)\n", x3, y3, z3);
zA = dy * (z2 - z1) + z1;
zB = dy * (z3 - z1) + z1;
// printf(" zA = %.2f zB = %.2f\n", zA, zB );
// printf(" xB - xA = %.2f\n", col_step * dy / row_step);
if ( dy > FG_EPSILON ) {
elev = dx * (zB - zA) / dy + zA;
} else {
elev = zA;
}
}
return(elev);
}
#if 0
// Write out a node file that can be used by the "triangle" program.
// Check for an optional "index.node.ex" file in case there is a .poly
// file to go along with this node file. Include these nodes first
// since they are referenced by position from the .poly file.
void FGArray::outputmesh_output_nodes( const string& fg_root, FGBucket& p )
{
double exnodes[MAX_EX_NODES][3];
struct stat stat_buf;
string dir, file;
char exfile[256];
#ifdef WIN32
char tmp_path[256];
#endif
string command;
FILE *fd;
int colmin, colmax, rowmin, rowmax;
int i, j, count, excount, result;
// determine dimensions
colmin = p.get_x() * ( (cols - 1) / 8);
colmax = colmin + ( (cols - 1) / 8);
rowmin = p.get_y() * ( (rows - 1) / 8);
rowmax = rowmin + ( (rows - 1) / 8);
cout << " dumping region = " << colmin << "," << rowmin << " to " <<
colmax << "," << rowmax << "\n";
// generate the base directory
string base_path = p.gen_base_path();
cout << " fg_root = " << fg_root << " Base Path = " << base_path << endl;
dir = fg_root + "/Scenery/" + base_path;
cout << " Dir = " << dir << endl;
// stat() directory and create if needed
errno = 0;
result = stat(dir.c_str(), &stat_buf);
if ( result != 0 && errno == ENOENT ) {
cout << " Creating directory\n";
command = "mkdir -p " + dir + "\n";
system( command.c_str() );
} else {
// assume directory exists
}
// get index and generate output file name
file = dir + "/" + p.gen_index_str() + ".node";
// get (optional) extra node file name (in case there is matching
// .poly file.
exfile = file + ".ex";
// load extra nodes if they exist
excount = 0;
if ( (fd = fopen(exfile, "r")) != NULL ) {
int junki;
fscanf(fd, "%d %d %d %d", &excount, &junki, &junki, &junki);
if ( excount > MAX_EX_NODES - 1 ) {
printf("Error, too many 'extra' nodes, increase array size\n");
exit(-1);
} else {
printf(" Expecting %d 'extra' nodes\n", excount);
}
for ( i = 1; i <= excount; i++ ) {
fscanf(fd, "%d %lf %lf %lf\n", &junki,
&exnodes[i][0], &exnodes[i][1], &exnodes[i][2]);
printf("(extra) %d %.2f %.2f %.2f\n",
i, exnodes[i][0], exnodes[i][1], exnodes[i][2]);
}
fclose(fd);
}
printf("Creating node file: %s\n", file);
fd = fopen(file, "w");
// first count regular nodes to generate header
count = 0;
for ( j = rowmin; j <= rowmax; j++ ) {
for ( i = colmin; i <= colmax; i++ ) {
if ( out_data[i][j] > -9000.0 ) {
count++;
}
}
// printf(" count = %d\n", count);
}
fprintf(fd, "%d 2 1 0\n", count + excount);
// now write out extra node data
for ( i = 1; i <= excount; i++ ) {
fprintf(fd, "%d %.2f %.2f %.2f\n",
i, exnodes[i][0], exnodes[i][1], exnodes[i][2]);
}
// write out actual node data
count = excount + 1;
for ( j = rowmin; j <= rowmax; j++ ) {
for ( i = colmin; i <= colmax; i++ ) {
if ( out_data[i][j] > -9000.0 ) {
fprintf(fd, "%d %.2f %.2f %.2f\n",
count++,
originx + (double)i * col_step,
originy + (double)j * row_step,
out_data[i][j]);
}
}
// printf(" count = %d\n", count);
}
fclose(fd);
}
#endif
FGArray::~FGArray( void ) {
// printf("class FGArray DEstructor called.\n");
delete [] in_data;
// delete [] out_data;
}
// $Log$
// Revision 1.7 1999/03/27 14:05:10 curt
// More sensible handling of the case where no dem file for this tile exists
// (or has been generated).
//
// Revision 1.6 1999/03/27 05:20:13 curt
// Handle corner nodes separately from the rest of the fitted nodes.
// Fixed some "const" related warnings.
//
// Revision 1.5 1999/03/25 19:03:50 curt
// Minor tweaks related to FGBucket usage.
//
// Revision 1.4 1999/03/20 20:32:51 curt
// First mostly successful tile triangulation works. There's plenty of tweaking
// to do, but we are marching in the right direction.
//
// Revision 1.3 1999/03/17 23:48:17 curt
// Removed forced -g compile flag.
// Fixed a couple compiler warnings.
//
// Revision 1.2 1999/03/13 23:50:26 curt
// Tweaked output formatting a bit.
//
// Revision 1.1 1999/03/13 18:45:02 curt
// Initial revision. (derived from libDEM.a code.)
//
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