1 // dem.cxx -- DEM management class
3 // Written by Curtis Olson, started March 1998.
5 // Copyright (C) 1998 Curtis L. Olson - curt@flightgear.org
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 // (Log is kept at end of this file)
29 #include <Include/compiler.h>
31 #include <ctype.h> // isspace()
32 #include <stdlib.h> // atoi()
33 #include <math.h> // rint()
37 #ifdef HAVE_SYS_STAT_H
38 # include <sys/stat.h> // stat()
41 #ifdef FG_HAVE_STD_INCLUDES
48 # include <unistd.h> // stat()
51 #include <Misc/fgstream.hxx>
52 #include <Misc/strutils.hxx>
53 #include <Include/fg_constants.h>
58 #define MAX_EX_NODES 10000
64 # define MKDIR(a) mkdir(a)
66 # define MKDIR(a) mkdir(a,S_IRWXU) // I am just guessing at this flag (NHV)
67 # endif // __BORLANDC__
72 FGDem::FGDem( void ) {
73 // cout << "class FGDem CONstructor called." << endl;
74 dem_data = new float[DEM_SIZE_1][DEM_SIZE_1];
75 output_data = new float[DEM_SIZE_1][DEM_SIZE_1];
79 FGDem::FGDem( const string &file ) {
80 // cout << "class FGDem CONstructor called." << endl;
81 dem_data = new float[DEM_SIZE_1][DEM_SIZE_1];
82 output_data = new float[DEM_SIZE_1][DEM_SIZE_1];
90 FGDem::open ( const string& file ) {
91 // open input file (or read from stdin)
93 printf("Loading DEM data file: stdin\n");
95 // fd = gzdopen(STDIN_FILENO, "r");
96 printf("Not yet ported ...\n");
99 in = new fg_gzifstream( file );
101 cout << "Cannot open " << file << endl;
104 cout << "Loading DEM data file: " << file << endl;
114 // the fg_gzifstream doesn't seem to have a close()
122 // return next token from input stream
124 FGDem::next_token() {
129 // cout << " returning " + token + "\n";
135 // return next integer from input stream
146 // return next double from input stream
148 FGDem::next_double() {
157 // return next exponential num from input stream
162 token = next_token();
164 const char* p = token.c_str();
168 for ( ; *p != 0; ++p )
176 return ::atof( buf );
180 // read and parse DEM "A" record
182 FGDem::read_a_record() {
188 // get the name field (144 characters)
189 for ( i = 0; i < 144; i++ ) {
194 // clean off the trailing whitespace
196 cout << " Quad name field: " << name << endl;
198 // DEM level code, 3 reflects processing by DMA
200 cout << " DEM level code = " << inum << "\n";
206 // Pattern code, 1 indicates a regular elevation pattern
208 cout << " Pattern code = " << inum << "\n";
210 // Planimetric reference system code, 0 indicates geographic
211 // coordinate system.
213 cout << " Planimetric reference code = " << inum << "\n";
217 cout << " Zone code = " << inum << "\n";
219 // Map projection parameters (ignored)
220 for ( i = 0; i < 15; i++ ) {
222 // printf("%d: %f\n",i,dnum);
225 // Units code, 3 represents arc-seconds as the unit of measure for
226 // ground planimetric coordinates throughout the file.
229 cout << " Unknown (X,Y) units code = " << inum << "!\n";
233 // Units code; 2 represents meters as the unit of measure for
234 // elevation coordinates throughout the file.
237 cout << " Unknown (Z) units code = " << inum << "!\n";
241 // Number (n) of sides in the polygon which defines the coverage of
242 // the DEM file (usually equal to 4).
245 cout << " Unknown polygon dimension = " << inum << "!\n";
249 // Ground coordinates of bounding box in arc-seconds
250 dem_x1 = originx = next_exp();
251 dem_y1 = originy = next_exp();
252 cout << " Origin = (" << originx << "," << originy << ")\n";
263 // Minimum/maximum elevations in meters
266 cout << " Elevation range " << dem_z1 << " to " << dem_z2 << "\n";
268 // Counterclockwise angle from the primary axis of ground
269 // planimetric referenced to the primary axis of the DEM local
271 token = next_token();
273 // Accuracy code; 0 indicates that a record of accuracy does not
274 // exist and that no record type C will follow.
276 // DEM spacial resolution. Usually (3,3,1) (3,6,1) or (3,9,1)
277 // depending on latitude
279 // I will eventually have to do something with this for data at
280 // higher latitudes */
281 token = next_token();
282 cout << " accuracy & spacial resolution string = " << token << endl;
284 cout << " length = " << i << "\n";
286 inum = atoi( token.substr( 0, i - 36 ) );
287 row_step = atof( token.substr( i - 24, 12 ) );
288 col_step = atof( token.substr( i - 36, 12 ) );
289 cout << " Accuracy code = " << inum << "\n";
290 cout << " column step = " << col_step <<
291 " row step = " << row_step << "\n";
293 // dimension of arrays to follow (1)
294 token = next_token();
296 // number of profiles
297 dem_num_profiles = cols = next_int();
298 cout << " Expecting " << dem_num_profiles << " profiles\n";
304 // read and parse DEM "B" record
306 FGDem::read_b_record( ) {
310 // row / column id of this profile
311 prof_row = next_int();
312 prof_col = next_int();
313 // printf("col id = %d row id = %d\n", prof_col, prof_row);
315 // Number of columns and rows (elevations) in this profile
316 prof_num_rows = rows = next_int();
317 prof_num_cols = next_int();
318 // printf(" profile num rows = %d\n", prof_num_rows);
320 // Ground planimetric coordinates (arc-seconds) of the first
321 // elevation in the profile
322 prof_x1 = next_exp();
323 prof_y1 = next_exp();
324 // printf(" Starting at %.2f %.2f\n", prof_x1, prof_y1);
326 // Elevation of local datum for the profile. Always zero for
327 // 1-degree DEM, the reference is mean sea level.
328 token = next_token();
330 // Minimum and maximum elevations for the profile.
331 token = next_token();
332 token = next_token();
334 // One (usually) dimensional array (prof_num_cols,1) of elevations
335 for ( i = 0; i < prof_num_rows; i++ ) {
336 prof_data = next_int();
337 dem_data[cur_col][i] = (float)prof_data;
349 if ( !read_a_record() ) {
353 for ( i = 0; i < dem_num_profiles; i++ ) {
354 // printf("Ready to read next b record\n");
358 if ( cur_col % 100 == 0 ) {
359 cout << " loaded " << cur_col << " profiles of data\n";
363 cout << " Done parsing\n";
369 // write out the area of data covered by the specified bucket. Data
370 // is written out column by column starting at the lower left hand
373 FGDem::write_area( const string& root, FGBucket& b, bool compress ) {
376 // calculate some boundaries
377 double min_x = ( b.get_center_lon() - 0.5 * b.get_width() ) * 3600.0;
378 double max_x = ( b.get_center_lon() + 0.5 * b.get_width() ) * 3600.0;
380 double min_y = ( b.get_center_lat() - 0.5 * b.get_height() ) * 3600.0;
381 double max_y = ( b.get_center_lat() + 0.5 * b.get_height() ) * 3600.0;
384 cout << "width = " << b.get_width() << " height = " << b.get_height()
387 int start_x = (int)((min_x - originx) / col_step);
388 int span_x = (int)(b.get_width() * 3600.0 / col_step);
390 int start_y = (int)((min_y - originy) / row_step);
391 int span_y = (int)(b.get_height() * 3600.0 / row_step);
393 cout << "start_x = " << start_x << " span_x = " << span_x << endl;
394 cout << "start_y = " << start_y << " span_y = " << span_y << endl;
396 // Do a simple sanity checking. But, please, please be nice to
397 // this write_area() routine and feed it buckets that coincide
398 // well with the underlying grid structure and spacing.
400 if ( ( min_x < originx )
401 || ( max_x > originx + cols * col_step )
402 || ( min_y < originy )
403 || ( max_y > originy + rows * row_step ) ) {
404 cout << " ERROR: bucket at least partially outside DEM data range!" <<
409 // generate output file name
410 string base = b.gen_base_path();
411 string path = root + "/Scenery/" + base;
412 string command = "mkdir -p " + path;
413 system( command.c_str() );
415 long int b_index = b.gen_index();
416 sprintf(tile_name, "%ld", b_index);
417 string demfile = path + "/" + tile_name + ".dem";
418 cout << "demfile = " << demfile << endl;
422 if ( (fp = fopen(demfile.c_str(), "w")) == NULL ) {
423 cout << "cannot open " << demfile << " for writing!" << endl;
427 fprintf( fp, "%d %d\n", (int)min_x, (int)min_y );
428 fprintf( fp, "%d %d %d %d\n", span_x + 1, (int)col_step,
429 span_y + 1, (int)row_step );
430 for ( int i = start_x; i <= start_x + span_x; ++i ) {
431 for ( int j = start_y; j <= start_y + span_y; ++j ) {
432 fprintf( fp, "%d ", (int)dem_data[i][j] );
439 string command = "gzip --best -f " + demfile;
440 system( command.c_str() );
449 // return the current altitude based on grid data. We should rewrite
450 // this to interpolate exact values, but for now this is good enough
451 double FGDem::interpolate_altitude( double lon, double lat ) {
452 // we expect incoming (lon,lat) to be in arcsec for now
454 double xlocal, ylocal, dx, dy, zA, zB, elev;
455 int x1, x2, x3, y1, y2, y3;
459 /* determine if we are in the lower triangle or the upper triangle
467 then calculate our end points
470 xlocal = (lon - originx) / col_step;
471 ylocal = (lat - originy) / row_step;
473 xindex = (int)(xlocal);
474 yindex = (int)(ylocal);
476 // printf("xindex = %d yindex = %d\n", xindex, yindex);
478 if ( xindex + 1 == cols ) {
482 if ( yindex + 1 == rows ) {
486 if ( (xindex < 0) || (xindex + 1 >= cols) ||
487 (yindex < 0) || (yindex + 1 >= rows) ) {
491 dx = xlocal - xindex;
492 dy = ylocal - yindex;
496 // printf(" Lower triangle\n");
500 z1 = dem_data[x1][y1];
504 z2 = dem_data[x2][y2];
508 z3 = dem_data[x3][y3];
510 // printf(" dx = %.2f dy = %.2f\n", dx, dy);
511 // printf(" (x1,y1,z1) = (%d,%d,%d)\n", x1, y1, z1);
512 // printf(" (x2,y2,z2) = (%d,%d,%d)\n", x2, y2, z2);
513 // printf(" (x3,y3,z3) = (%d,%d,%d)\n", x3, y3, z3);
515 zA = dx * (z2 - z1) + z1;
516 zB = dx * (z3 - z1) + z1;
518 // printf(" zA = %.2f zB = %.2f\n", zA, zB);
520 if ( dx > FG_EPSILON ) {
521 elev = dy * (zB - zA) / dx + zA;
527 // printf(" Upper triangle\n");
531 z1 = dem_data[x1][y1];
535 z2 = dem_data[x2][y2];
539 z3 = dem_data[x3][y3];
541 // printf(" dx = %.2f dy = %.2f\n", dx, dy);
542 // printf(" (x1,y1,z1) = (%d,%d,%d)\n", x1, y1, z1);
543 // printf(" (x2,y2,z2) = (%d,%d,%d)\n", x2, y2, z2);
544 // printf(" (x3,y3,z3) = (%d,%d,%d)\n", x3, y3, z3);
546 zA = dy * (z2 - z1) + z1;
547 zB = dy * (z3 - z1) + z1;
549 // printf(" zA = %.2f zB = %.2f\n", zA, zB );
550 // printf(" xB - xA = %.2f\n", col_step * dy / row_step);
552 if ( dy > FG_EPSILON ) {
553 elev = dx * (zB - zA) / dy + zA;
563 // Use least squares to fit a simpler data set to dem data
564 void FGDem::fit( double error, FGBucket& p ) {
565 double x[DEM_SIZE_1], y[DEM_SIZE_1];
566 double m, b, ave_error, max_error;
568 int n, row, start, end;
569 int colmin, colmax, rowmin, rowmax;
571 // FILE *dem, *fit, *fit1;
573 printf("Initializing output mesh structure\n");
576 // determine dimensions
577 colmin = p.get_x() * ( (cols - 1) / 8);
578 colmax = colmin + ( (cols - 1) / 8);
579 rowmin = p.get_y() * ( (rows - 1) / 8);
580 rowmax = rowmin + ( (rows - 1) / 8);
581 printf("Fitting region = %d,%d to %d,%d\n", colmin, rowmin, colmax, rowmax);
583 // include the corners explicitly
584 outputmesh_set_pt(colmin, rowmin, dem_data[colmin][rowmin]);
585 outputmesh_set_pt(colmin, rowmax, dem_data[colmin][rowmax]);
586 outputmesh_set_pt(colmax, rowmax, dem_data[colmax][rowmax]);
587 outputmesh_set_pt(colmax, rowmin, dem_data[colmax][rowmin]);
589 printf("Beginning best fit procedure\n");
591 for ( row = rowmin; row <= rowmax; row++ ) {
592 // fit = fopen("fit.dat", "w");
593 // fit1 = fopen("fit1.dat", "w");
597 // printf(" fitting row = %d\n", row);
599 while ( start < colmax ) {
603 x[(end - start) - 1] = 0.0 + ( start * col_step );
604 y[(end - start) - 1] = dem_data[start][row];
606 while ( (end <= colmax) && good_fit ) {
607 n = (end - start) + 1;
608 // printf("Least square of first %d points\n", n);
609 x[end - start] = 0.0 + ( end * col_step );
610 y[end - start] = dem_data[end][row];
611 least_squares(x, y, n, &m, &b);
612 ave_error = least_squares_error(x, y, n, m, b);
613 max_error = least_squares_max_error(x, y, n, m, b);
616 printf("%d - %d ave error = %.2f max error = %.2f y = %.2f*x + %.2f\n",
617 start, end, ave_error, max_error, m, b);
619 f = fopen("gnuplot.dat", "w");
620 for ( j = 0; j <= end; j++) {
621 fprintf(f, "%.2f %.2f\n", 0.0 + ( j * col_step ),
624 for ( j = start; j <= end; j++) {
625 fprintf(f, "%.2f %.2f\n", 0.0 + ( j * col_step ),
630 printf("Please hit return: "); gets(junk);
633 if ( max_error > error ) {
641 // error exceeded the threshold, back up
642 end -= 2; // back "end" up to the last good enough fit
643 n--; // back "n" up appropriately too
645 // we popped out of the above loop while still within
646 // the error threshold, so we must be at the end of
651 least_squares(x, y, n, &m, &b);
652 ave_error = least_squares_error(x, y, n, m, b);
653 max_error = least_squares_max_error(x, y, n, m, b);
657 printf("%d - %d ave error = %.2f max error = %.2f y = %.2f*x + %.2f\n",
658 start, end, ave_error, max_error, m, b);
661 fprintf(fit1, "%.2f %.2f\n", x[0], m * x[0] + b);
662 fprintf(fit1, "%.2f %.2f\n", x[end-start], m * x[end-start] + b);
665 if ( start > colmin ) {
666 // skip this for the first line segment
668 outputmesh_set_pt(start, row, (lasty + cury) / 2);
669 // fprintf(fit, "%.2f %.2f\n", x[0], (lasty + cury) / 2);
672 lasty = m * x[end-start] + b;
680 dem = fopen("gnuplot.dat", "w");
681 for ( j = 0; j < DEM_SIZE_1; j++) {
682 fprintf(dem, "%.2f %.2f\n", 0.0 + ( j * col_step ),
688 // NOTICE, this is for testing only. This instance of
689 // output_nodes should be removed. It should be called only
690 // once at the end once all the nodes have been generated.
691 // newmesh_output_nodes(&nm, "mesh.node");
692 // printf("Please hit return: "); gets(junk);
695 // outputmesh_output_nodes(fg_root, p);
699 // Initialize output mesh structure
700 void FGDem::outputmesh_init( void ) {
703 for ( j = 0; j < DEM_SIZE_1; j++ ) {
704 for ( i = 0; i < DEM_SIZE_1; i++ ) {
705 output_data[i][j] = -9999.0;
711 // Get the value of a mesh node
712 double FGDem::outputmesh_get_pt( int i, int j ) {
713 return ( output_data[i][j] );
717 // Set the value of a mesh node
718 void FGDem::outputmesh_set_pt( int i, int j, double value ) {
719 // printf("Setting data[%d][%d] = %.2f\n", i, j, value);
720 output_data[i][j] = value;
724 // Write out a node file that can be used by the "triangle" program.
725 // Check for an optional "index.node.ex" file in case there is a .poly
726 // file to go along with this node file. Include these nodes first
727 // since they are referenced by position from the .poly file.
728 void FGDem::outputmesh_output_nodes( const string& fg_root, FGBucket& p )
730 double exnodes[MAX_EX_NODES][3];
731 struct stat stat_buf;
733 char file[256], exfile[256];
740 int colmin, colmax, rowmin, rowmax;
741 int i, j, count, excount, result;
743 // determine dimensions
744 colmin = p.get_x() * ( (cols - 1) / 8);
745 colmax = colmin + ( (cols - 1) / 8);
746 rowmin = p.get_y() * ( (rows - 1) / 8);
747 rowmax = rowmin + ( (rows - 1) / 8);
748 cout << " dumping region = " << colmin << "," << rowmin << " to " <<
749 colmax << "," << rowmax << "\n";
751 // generate the base directory
752 string base_path = p.gen_base_path();
753 cout << "fg_root = " << fg_root << " Base Path = " << base_path << endl;
754 dir = fg_root + "/Scenery/" + base_path;
755 cout << "Dir = " << dir << endl;
757 // stat() directory and create if needed
759 result = stat(dir.c_str(), &stat_buf);
760 if ( result != 0 && errno == ENOENT ) {
761 cout << "Creating directory\n";
765 command = "mkdir -p " + dir + "\n";
766 system( command.c_str() );
771 // Cygwin crashes when trying to output to node file
772 // explicitly making directory structure seems OK on Win95
774 extract_path (base_path, tmp_path);
776 dir = fg_root + "/Scenery";
777 if (my_mkdir ( dir.c_str() )) { exit (-1); }
779 dir = fg_root + "/Scenery/" + tmp_path;
780 if (my_mkdir ( dir.c_str() )) { exit (-1); }
782 dir = fg_root + "/Scenery/" + base_path;
783 if (my_mkdir ( dir.c_str() )) { exit (-1); }
789 // assume directory exists
792 // get index and generate output file name
793 index = p.gen_index();
794 sprintf(file, "%s/%ld.node", dir.c_str(), index);
796 // get (optional) extra node file name (in case there is matching
798 strcpy(exfile, file);
799 strcat(exfile, ".ex");
801 // load extra nodes if they exist
803 if ( (fd = fopen(exfile, "r")) != NULL ) {
805 fscanf(fd, "%d %d %d %d", &excount, &junki, &junki, &junki);
807 if ( excount > MAX_EX_NODES - 1 ) {
808 printf("Error, too many 'extra' nodes, increase array size\n");
811 printf(" Expecting %d 'extra' nodes\n", excount);
814 for ( i = 1; i <= excount; i++ ) {
815 fscanf(fd, "%d %lf %lf %lf\n", &junki,
816 &exnodes[i][0], &exnodes[i][1], &exnodes[i][2]);
817 printf("(extra) %d %.2f %.2f %.2f\n",
818 i, exnodes[i][0], exnodes[i][1], exnodes[i][2]);
823 printf("Creating node file: %s\n", file);
824 fd = fopen(file, "w");
826 // first count regular nodes to generate header
828 for ( j = rowmin; j <= rowmax; j++ ) {
829 for ( i = colmin; i <= colmax; i++ ) {
830 if ( output_data[i][j] > -9000.0 ) {
834 // printf(" count = %d\n", count);
836 fprintf(fd, "%d 2 1 0\n", count + excount);
838 // now write out extra node data
839 for ( i = 1; i <= excount; i++ ) {
840 fprintf(fd, "%d %.2f %.2f %.2f\n",
841 i, exnodes[i][0], exnodes[i][1], exnodes[i][2]);
844 // write out actual node data
846 for ( j = rowmin; j <= rowmax; j++ ) {
847 for ( i = colmin; i <= colmax; i++ ) {
848 if ( output_data[i][j] > -9000.0 ) {
849 fprintf(fd, "%d %.2f %.2f %.2f\n",
851 originx + (double)i * col_step,
852 originy + (double)j * row_step,
856 // printf(" count = %d\n", count);
864 FGDem::~FGDem( void ) {
865 // printf("class FGDem DEstructor called.\n");
867 delete [] output_data;
872 // Revision 1.26 1999/03/13 17:40:37 curt
873 // Moved point interpolation and least squares fitting to contruction program
875 // Moved leastsqs.* to Lib/Math/
877 // Revision 1.25 1999/03/12 22:53:07 curt
878 // Added a routine to dump out the portion of the dem data covered by a
879 // specified bucket. Other changes related to needs of scenery tools overhaul.
881 // Revision 1.24 1999/03/11 23:31:56 curt
882 // Tweaks to use newbucket.hxx
884 // Revision 1.23 1999/03/10 01:09:12 curt
885 // Tweaks to go along with scenery tools overhaul.
886 // Added a new constructor that accepts the file name.
888 // Revision 1.22 1999/01/19 20:56:56 curt
889 // MacOS portability changes contributed by "Robert Puyol" <puyol@abvent.fr>
891 // Revision 1.21 1998/11/06 14:04:32 curt
892 // Changes due to updates in fgstream.
894 // Revision 1.20 1998/10/28 19:38:20 curt
895 // Elliminate some unnecessary win32 specific stuff (by Norman Vine)
897 // Revision 1.19 1998/10/22 21:59:19 curt
898 // Fixed a couple subtle bugs that resulted from some of my c++ conversions.
899 // One bug could cause a segfault on certain input, and the other bug could
900 // cause the whole procedure to go balistic and generate huge files (also only
901 // on rare input combinations.)
903 // Revision 1.18 1998/10/18 01:17:09 curt
906 // Revision 1.17 1998/10/16 19:08:12 curt
907 // Portability updates from Bernie Bright.
909 // Revision 1.16 1998/10/02 21:41:39 curt
912 // Revision 1.15 1998/09/21 20:53:59 curt
913 // minor tweaks to clean a few additional things up after the rewrite.
915 // Revision 1.14 1998/09/19 17:59:45 curt
916 // Use c++ streams (fg_gzifstream). Also converted many character arrays to
919 // Revision 1.13 1998/09/09 16:24:04 curt
920 // Fixed a bug in the handling of exclude files which was causing
921 // a crash by calling fclose() on an invalid file handle.
923 // Revision 1.12 1998/08/24 20:03:31 curt
924 // Eliminated a possible memory overrun error.
925 // Use the proper free() rather than the incorrect delete().
927 // Revision 1.11 1998/07/20 12:46:11 curt
928 // When outputing to a .node file, first check for an optional
929 // "index.node.ex" file in case there is a .poly file to go along with this
930 // node file. Include these nodes first since they are referenced by position
931 // from the .poly file. This is my first pass at adding an area "cutout"
932 // feature to the terrain generation pipeline.
934 // Revision 1.10 1998/07/13 20:58:02 curt
937 // Revision 1.9 1998/07/13 15:29:49 curt
938 // Added #ifdef HAVE_CONFIG_H
940 // Revision 1.8 1998/07/04 00:47:18 curt
941 // typedef'd struct fgBUCKET.
943 // Revision 1.7 1998/06/05 18:14:39 curt
944 // Abort out early when reading the "A" record if it doesn't look like
945 // a proper DEM file.
947 // Revision 1.6 1998/05/02 01:49:21 curt
948 // Fixed a bug where the wrong variable was being initialized.
950 // Revision 1.5 1998/04/25 15:00:32 curt
951 // Changed "r" to "rb" in gzopen() options. This fixes bad behavior in win32.
953 // Revision 1.4 1998/04/22 13:14:46 curt
954 // Fixed a bug in zlib usage.
956 // Revision 1.3 1998/04/18 03:53:05 curt
957 // Added zlib support.
959 // Revision 1.2 1998/04/14 02:43:27 curt
960 // Used "new" to auto-allocate large DEM parsing arrays in class constructor.
962 // Revision 1.1 1998/04/08 22:57:22 curt
963 // Adopted Gnu automake/autoconf system.
965 // Revision 1.3 1998/04/06 21:09:41 curt
966 // Additional win32 support.
967 // Fixed a bad bug in dem file parsing that was causing the output to be
968 // flipped about x = y.
970 // Revision 1.2 1998/03/23 20:35:41 curt
971 // Updated to use FG_EPSILON
973 // Revision 1.1 1998/03/19 02:54:47 curt
974 // Reorganized into a class lib called fgDEM.
976 // Revision 1.1 1998/03/19 01:46:28 curt