// dem.cxx -- DEM management class // // Written by Curtis Olson, started March 1998. // // Copyright (C) 1998 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 #endif #include #include // isspace() #include // atoi() #include // rint() #include #include #ifdef HAVE_SYS_STAT_H # include // stat() #endif #ifdef FG_HAVE_STD_INCLUDES # include #else # include #endif #ifdef HAVE_UNISTD_H # include // stat() #endif #include #include #include #include "dem.hxx" #define MAX_EX_NODES 10000 #if 0 #ifdef WIN32 # ifdef __BORLANDC__ # include # define MKDIR(a) mkdir(a) # else # define MKDIR(a) mkdir(a,S_IRWXU) // I am just guessing at this flag (NHV) # endif // __BORLANDC__ #endif // WIN32 #endif //0 FGDem::FGDem( void ) { // cout << "class FGDem CONstructor called." << endl; dem_data = new float[DEM_SIZE_1][DEM_SIZE_1]; output_data = new float[DEM_SIZE_1][DEM_SIZE_1]; } FGDem::FGDem( const string &file ) { // cout << "class FGDem CONstructor called." << endl; dem_data = new float[DEM_SIZE_1][DEM_SIZE_1]; output_data = new float[DEM_SIZE_1][DEM_SIZE_1]; FGDem::open(file); } // open a DEM file int FGDem::open ( const string& file ) { // open input file (or read from stdin) if ( file == "-" ) { printf("Loading DEM data file: stdin\n"); // fd = stdin; // fd = gzdopen(STDIN_FILENO, "r"); printf("Not yet ported ...\n"); return 0; } else { in = new fg_gzifstream( file ); if ( !(*in) ) { cout << "Cannot open " << file << endl; return 0; } cout << "Loading DEM data file: " << file << endl; } return 1; } // close a DEM file int FGDem::close () { // the fg_gzifstream doesn't seem to have a close() delete in; return 1; } // return next token from input stream string FGDem::next_token() { string token; *in >> token; // cout << " returning " + token + "\n"; return token; } // return next integer from input stream int FGDem::next_int() { int result; *in >> result; return result; } // return next double from input stream double FGDem::next_double() { double result; *in >> result; return result; } // return next exponential num from input stream double FGDem::next_exp() { string token; token = next_token(); const char* p = token.c_str(); char buf[64]; char* bp = buf; for ( ; *p != 0; ++p ) { if ( *p == 'D' ) *bp++ = 'E'; else *bp++ = *p; } *bp = 0; return ::atof( buf ); } // read and parse DEM "A" record int FGDem::read_a_record() { int i, inum; double dnum; string name, token; char c; // get the name field (144 characters) for ( i = 0; i < 144; i++ ) { in->get(c); name += c; } // clean off the trailing whitespace name = trim(name); cout << " Quad name field: " << name << endl; // DEM level code, 3 reflects processing by DMA inum = next_int(); cout << " DEM level code = " << inum << "\n"; if ( inum > 3 ) { return 0; } // Pattern code, 1 indicates a regular elevation pattern inum = next_int(); cout << " Pattern code = " << inum << "\n"; // Planimetric reference system code, 0 indicates geographic // coordinate system. inum = next_int(); cout << " Planimetric reference code = " << inum << "\n"; // Zone code inum = next_int(); cout << " Zone code = " << inum << "\n"; // Map projection parameters (ignored) for ( i = 0; i < 15; i++ ) { dnum = next_exp(); // printf("%d: %f\n",i,dnum); } // Units code, 3 represents arc-seconds as the unit of measure for // ground planimetric coordinates throughout the file. inum = next_int(); if ( inum != 3 ) { cout << " Unknown (X,Y) units code = " << inum << "!\n"; exit(-1); } // Units code; 2 represents meters as the unit of measure for // elevation coordinates throughout the file. inum = next_int(); if ( inum != 2 ) { cout << " Unknown (Z) units code = " << inum << "!\n"; exit(-1); } // Number (n) of sides in the polygon which defines the coverage of // the DEM file (usually equal to 4). inum = next_int(); if ( inum != 4 ) { cout << " Unknown polygon dimension = " << inum << "!\n"; exit(-1); } // Ground coordinates of bounding box in arc-seconds dem_x1 = originx = next_exp(); dem_y1 = originy = next_exp(); cout << " Origin = (" << originx << "," << originy << ")\n"; dem_x2 = next_exp(); dem_y2 = next_exp(); dem_x3 = next_exp(); dem_y3 = next_exp(); dem_x4 = next_exp(); dem_y4 = next_exp(); // Minimum/maximum elevations in meters dem_z1 = next_exp(); dem_z2 = next_exp(); cout << " Elevation range " << dem_z1 << " to " << dem_z2 << "\n"; // Counterclockwise angle from the primary axis of ground // planimetric referenced to the primary axis of the DEM local // reference system. token = next_token(); // Accuracy code; 0 indicates that a record of accuracy does not // exist and that no record type C will follow. // DEM spacial resolution. Usually (3,3,1) (3,6,1) or (3,9,1) // depending on latitude // I will eventually have to do something with this for data at // higher latitudes */ token = next_token(); cout << " accuracy & spacial resolution string = " << token << endl; i = token.length(); cout << " length = " << i << "\n"; inum = atoi( token.substr( 0, i - 36 ) ); row_step = atof( token.substr( i - 24, 12 ) ); col_step = atof( token.substr( i - 36, 12 ) ); cout << " Accuracy code = " << inum << "\n"; cout << " column step = " << col_step << " row step = " << row_step << "\n"; // dimension of arrays to follow (1) token = next_token(); // number of profiles dem_num_profiles = cols = next_int(); cout << " Expecting " << dem_num_profiles << " profiles\n"; return 1; } // read and parse DEM "B" record void FGDem::read_b_record( ) { string token; int i; // row / column id of this profile prof_row = next_int(); prof_col = next_int(); // printf("col id = %d row id = %d\n", prof_col, prof_row); // Number of columns and rows (elevations) in this profile prof_num_rows = rows = next_int(); prof_num_cols = next_int(); // printf(" profile num rows = %d\n", prof_num_rows); // Ground planimetric coordinates (arc-seconds) of the first // elevation in the profile prof_x1 = next_exp(); prof_y1 = next_exp(); // printf(" Starting at %.2f %.2f\n", prof_x1, prof_y1); // Elevation of local datum for the profile. Always zero for // 1-degree DEM, the reference is mean sea level. token = next_token(); // Minimum and maximum elevations for the profile. token = next_token(); token = next_token(); // One (usually) dimensional array (prof_num_cols,1) of elevations for ( i = 0; i < prof_num_rows; i++ ) { prof_data = next_int(); dem_data[cur_col][i] = (float)prof_data; } } // parse dem file int FGDem::parse( ) { int i; cur_col = 0; if ( !read_a_record() ) { return(0); } for ( i = 0; i < dem_num_profiles; i++ ) { // printf("Ready to read next b record\n"); read_b_record(); cur_col++; if ( cur_col % 100 == 0 ) { cout << " loaded " << cur_col << " profiles of data\n"; } } cout << " Done parsing\n"; return 1; } // 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. int FGDem::write_area( const string& root, FGBucket& b, bool compress ) { // 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; 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 DEM data range!" << endl; return 0; } // generate output file name string base = b.gen_base_path(); string path = root + "/Scenery/" + base; string command = "mkdir -p " + path; system( command.c_str() ); string demfile = path + "/" + b.gen_index_str() + ".dem"; cout << "demfile = " << demfile << endl; // write the file FILE *fp; if ( (fp = fopen(demfile.c_str(), "w")) == NULL ) { cout << "cannot open " << demfile << " for writing!" << endl; exit(-1); } fprintf( fp, "%d %d\n", (int)min_x, (int)min_y ); fprintf( 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 ) { fprintf( fp, "%d ", (int)dem_data[i][j] ); } fprintf( fp, "\n" ); } fclose(fp); if ( compress ) { string command = "gzip --best -f " + demfile; system( command.c_str() ); } return 1; } #if 0 // return the current altitude based on grid data. We should rewrite // this to interpolate exact values, but for now this is good enough double FGDem::interpolate_altitude( double lon, double lat ) { // 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) ) { return(-9999); } dx = xlocal - xindex; dy = ylocal - yindex; if ( dx > dy ) { // lower triangle // printf(" Lower triangle\n"); x1 = xindex; y1 = yindex; z1 = dem_data[x1][y1]; x2 = xindex + 1; y2 = yindex; z2 = dem_data[x2][y2]; x3 = xindex + 1; y3 = yindex + 1; z3 = dem_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 = dem_data[x1][y1]; x2 = xindex; y2 = yindex + 1; z2 = dem_data[x2][y2]; x3 = xindex + 1; y3 = yindex + 1; z3 = dem_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); } // Use least squares to fit a simpler data set to dem data void FGDem::fit( double error, FGBucket& p ) { double x[DEM_SIZE_1], y[DEM_SIZE_1]; double m, b, ave_error, max_error; double cury, lasty; int n, row, start, end; int colmin, colmax, rowmin, rowmax; bool good_fit; // FILE *dem, *fit, *fit1; printf("Initializing output mesh structure\n"); outputmesh_init(); // 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); printf("Fitting region = %d,%d to %d,%d\n", colmin, rowmin, colmax, rowmax); // include the corners explicitly outputmesh_set_pt(colmin, rowmin, dem_data[colmin][rowmin]); outputmesh_set_pt(colmin, rowmax, dem_data[colmin][rowmax]); outputmesh_set_pt(colmax, rowmax, dem_data[colmax][rowmax]); outputmesh_set_pt(colmax, rowmin, dem_data[colmax][rowmin]); printf("Beginning best fit procedure\n"); for ( row = rowmin; row <= rowmax; row++ ) { // fit = fopen("fit.dat", "w"); // fit1 = fopen("fit1.dat", "w"); start = colmin; // printf(" fitting row = %d\n", row); while ( start < colmax ) { end = start + 1; good_fit = true; x[(end - start) - 1] = 0.0 + ( start * col_step ); y[(end - start) - 1] = dem_data[start][row]; while ( (end <= colmax) && good_fit ) { n = (end - start) + 1; // printf("Least square of first %d points\n", n); x[end - start] = 0.0 + ( end * col_step ); y[end - start] = dem_data[end][row]; 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("%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 ), dem_data[row][j]); } for ( j = start; j <= end; j++) { fprintf(f, "%.2f %.2f\n", 0.0 + ( j * col_step ), dem_data[row][j]); } fclose(f); printf("Please hit return: "); gets(junk); */ if ( max_error > error ) { 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; outputmesh_set_pt(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 < DEM_SIZE_1; j++) { fprintf(dem, "%.2f %.2f\n", 0.0 + ( j * col_step ), dem_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); } // Initialize output mesh structure void FGDem::outputmesh_init( void ) { int i, j; for ( j = 0; j < DEM_SIZE_1; j++ ) { for ( i = 0; i < DEM_SIZE_1; i++ ) { output_data[i][j] = -9999.0; } } } // Get the value of a mesh node double FGDem::outputmesh_get_pt( int i, int j ) { return ( output_data[i][j] ); } // Set the value of a mesh node void FGDem::outputmesh_set_pt( int i, int j, double value ) { // printf("Setting data[%d][%d] = %.2f\n", i, j, value); output_data[i][j] = value; } // 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 FGDem::outputmesh_output_nodes( const string& fg_root, FGBucket& p ) { double exnodes[MAX_EX_NODES][3]; struct stat stat_buf; string dir; char file[256], exfile[256]; #ifdef WIN32 char tmp_path[256]; #endif string command; FILE *fd; long int index; 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"; // #ifndef WIN32 command = "mkdir -p " + dir + "\n"; system( command.c_str() ); #if 0 // #else // WIN32 // Cygwin crashes when trying to output to node file // explicitly making directory structure seems OK on Win95 extract_path (base_path, tmp_path); dir = fg_root + "/Scenery"; if (my_mkdir ( dir.c_str() )) { exit (-1); } dir = fg_root + "/Scenery/" + tmp_path; if (my_mkdir ( dir.c_str() )) { exit (-1); } dir = fg_root + "/Scenery/" + base_path; if (my_mkdir ( dir.c_str() )) { exit (-1); } // #endif // WIN32 #endif //0 } else { // assume directory exists } // get index and generate output file name index = p.gen_index(); sprintf(file, "%s/%ld.node", dir.c_str(), index); // get (optional) extra node file name (in case there is matching // .poly file. strcpy(exfile, file); strcat(exfile, ".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 ( output_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 ( output_data[i][j] > -9000.0 ) { fprintf(fd, "%d %.2f %.2f %.2f\n", count++, originx + (double)i * col_step, originy + (double)j * row_step, output_data[i][j]); } } // printf(" count = %d\n", count); } fclose(fd); } #endif FGDem::~FGDem( void ) { // printf("class FGDem DEstructor called.\n"); delete [] dem_data; delete [] output_data; } // $Log$ // Revision 1.27 1999/03/25 19:04:36 curt // Minor tweaks related to FGBucket usage. // // Revision 1.26 1999/03/13 17:40:37 curt // Moved point interpolation and least squares fitting to contruction program // area. // Moved leastsqs.* to Lib/Math/ // // Revision 1.25 1999/03/12 22:53:07 curt // Added a routine to dump out the portion of the dem data covered by a // specified bucket. Other changes related to needs of scenery tools overhaul. // // Revision 1.24 1999/03/11 23:31:56 curt // Tweaks to use newbucket.hxx // // Revision 1.23 1999/03/10 01:09:12 curt // Tweaks to go along with scenery tools overhaul. // Added a new constructor that accepts the file name. // // Revision 1.22 1999/01/19 20:56:56 curt // MacOS portability changes contributed by "Robert Puyol" // // Revision 1.21 1998/11/06 14:04:32 curt // Changes due to updates in fgstream. // // Revision 1.20 1998/10/28 19:38:20 curt // Elliminate some unnecessary win32 specific stuff (by Norman Vine) // // Revision 1.19 1998/10/22 21:59:19 curt // Fixed a couple subtle bugs that resulted from some of my c++ conversions. // One bug could cause a segfault on certain input, and the other bug could // cause the whole procedure to go balistic and generate huge files (also only // on rare input combinations.) // // Revision 1.18 1998/10/18 01:17:09 curt // Point3D tweaks. // // Revision 1.17 1998/10/16 19:08:12 curt // Portability updates from Bernie Bright. // // Revision 1.16 1998/10/02 21:41:39 curt // Fixes for win32. // // Revision 1.15 1998/09/21 20:53:59 curt // minor tweaks to clean a few additional things up after the rewrite. // // Revision 1.14 1998/09/19 17:59:45 curt // Use c++ streams (fg_gzifstream). Also converted many character arrays to // the string class. // // Revision 1.13 1998/09/09 16:24:04 curt // Fixed a bug in the handling of exclude files which was causing // a crash by calling fclose() on an invalid file handle. // // Revision 1.12 1998/08/24 20:03:31 curt // Eliminated a possible memory overrun error. // Use the proper free() rather than the incorrect delete(). // // Revision 1.11 1998/07/20 12:46:11 curt // When outputing to a .node file, first 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. This is my first pass at adding an area "cutout" // feature to the terrain generation pipeline. // // Revision 1.10 1998/07/13 20:58:02 curt // . // // Revision 1.9 1998/07/13 15:29:49 curt // Added #ifdef HAVE_CONFIG_H // // Revision 1.8 1998/07/04 00:47:18 curt // typedef'd struct fgBUCKET. // // Revision 1.7 1998/06/05 18:14:39 curt // Abort out early when reading the "A" record if it doesn't look like // a proper DEM file. // // Revision 1.6 1998/05/02 01:49:21 curt // Fixed a bug where the wrong variable was being initialized. // // Revision 1.5 1998/04/25 15:00:32 curt // Changed "r" to "rb" in gzopen() options. This fixes bad behavior in win32. // // Revision 1.4 1998/04/22 13:14:46 curt // Fixed a bug in zlib usage. // // Revision 1.3 1998/04/18 03:53:05 curt // Added zlib support. // // Revision 1.2 1998/04/14 02:43:27 curt // Used "new" to auto-allocate large DEM parsing arrays in class constructor. // // Revision 1.1 1998/04/08 22:57:22 curt // Adopted Gnu automake/autoconf system. // // Revision 1.3 1998/04/06 21:09:41 curt // Additional win32 support. // Fixed a bad bug in dem file parsing that was causing the output to be // flipped about x = y. // // Revision 1.2 1998/03/23 20:35:41 curt // Updated to use FG_EPSILON // // Revision 1.1 1998/03/19 02:54:47 curt // Reorganized into a class lib called fgDEM. // // Revision 1.1 1998/03/19 01:46:28 curt // Initial revision. //