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Commit | Line | Data |
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f6171fe3 EB |
1 | /* |
2 | * viking -- GPS Data and Topo Analyzer, Explorer, and Manager | |
3 | * | |
4 | * Copyright (C) 2003-2008, Evan Battaglia <gtoevan@gmx.net> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
19 | * | |
20 | */ | |
21 | ||
72b6a3ed JB |
22 | #ifdef HAVE_CONFIG_H |
23 | #include "config.h" | |
24 | #endif | |
25 | ||
ad0a8c2d EB |
26 | #include <stdio.h> |
27 | #include <string.h> | |
28 | #include <glib.h> | |
29 | #include <math.h> | |
30 | #include <stdlib.h> | |
46e4fa54 QT |
31 | #include <zlib.h> |
32 | #include <sys/types.h> | |
33 | #include <sys/stat.h> | |
31766324 MA |
34 | #ifdef HAVE_UNISTD_H |
35 | #include <unistd.h> | |
36 | #endif | |
46e4fa54 | 37 | |
6af463da | 38 | #include <glib/gstdio.h> |
4c77d5e0 GB |
39 | #include <glib/gi18n.h> |
40 | ||
ad0a8c2d EB |
41 | #include "dem.h" |
42 | #include "file.h" | |
43 | ||
44 | #define DEM_BLOCK_SIZE 1024 | |
45 | #define GET_COLUMN(dem,n) ((VikDEMColumn *)g_ptr_array_index( (dem)->columns, (n) )) | |
46 | ||
47 | static gboolean get_double_and_continue ( gchar **buffer, gdouble *tmp, gboolean warn ) | |
48 | { | |
49 | gchar *endptr; | |
50 | *tmp = g_strtod(*buffer, &endptr); | |
51 | if ( endptr == NULL|| endptr == *buffer ) { | |
52 | if ( warn ) | |
4c77d5e0 | 53 | g_warning(_("Invalid DEM")); |
ad0a8c2d EB |
54 | return FALSE; |
55 | } | |
56 | *buffer=endptr; | |
57 | return TRUE; | |
58 | } | |
59 | ||
60 | ||
61 | static gboolean get_int_and_continue ( gchar **buffer, gint *tmp, gboolean warn ) | |
62 | { | |
63 | gchar *endptr; | |
64 | *tmp = strtol(*buffer, &endptr, 10); | |
65 | if ( endptr == NULL|| endptr == *buffer ) { | |
66 | if ( warn ) | |
4c77d5e0 | 67 | g_warning(_("Invalid DEM")); |
ad0a8c2d EB |
68 | return FALSE; |
69 | } | |
70 | *buffer=endptr; | |
71 | return TRUE; | |
72 | } | |
73 | ||
74 | static gboolean dem_parse_header ( gchar *buffer, VikDEM *dem ) | |
75 | { | |
76 | gdouble val; | |
77 | gint int_val; | |
78 | guint i; | |
79 | gchar *tmp = buffer; | |
80 | ||
81 | /* incomplete header */ | |
82 | if ( strlen(buffer) != 1024 ) | |
83 | return FALSE; | |
84 | ||
85 | /* fix Fortran-style exponentiation 1.0D5 -> 1.0E5 */ | |
86 | while (*tmp) { | |
87 | if ( *tmp=='D') | |
88 | *tmp='E'; | |
89 | tmp++; | |
90 | } | |
91 | ||
92 | /* skip name */ | |
93 | buffer += 149; | |
94 | ||
95 | /* "DEM level code, pattern code, palaimetric reference system code" -- skip */ | |
96 | get_int_and_continue(&buffer, &int_val, TRUE); | |
97 | get_int_and_continue(&buffer, &int_val, TRUE); | |
98 | get_int_and_continue(&buffer, &int_val, TRUE); | |
99 | ||
100 | /* zone */ | |
101 | get_int_and_continue(&buffer, &int_val, TRUE); | |
102 | dem->utm_zone = int_val; | |
103 | /* TODO -- southern or northern hemisphere?! */ | |
104 | dem->utm_letter = 'N'; | |
105 | ||
106 | /* skip numbers 5-19 */ | |
107 | for ( i = 0; i < 15; i++ ) { | |
108 | if ( ! get_double_and_continue(&buffer, &val, FALSE) ) { | |
4c77d5e0 | 109 | g_warning (_("Invalid DEM header")); |
ad0a8c2d EB |
110 | return FALSE; |
111 | } | |
112 | } | |
113 | ||
114 | /* number 20 -- horizontal unit code (utm/ll) */ | |
115 | get_double_and_continue(&buffer, &val, TRUE); | |
116 | dem->horiz_units = val; | |
117 | get_double_and_continue(&buffer, &val, TRUE); | |
70147e60 | 118 | /* dem->orig_vert_units = val; now done below */ |
ad0a8c2d EB |
119 | |
120 | /* TODO: do this for real. these are only for 1:24k and 1:250k USGS */ | |
121 | if ( dem->horiz_units == VIK_DEM_HORIZ_UTM_METERS ) { | |
122 | dem->east_scale = 10.0; /* meters */ | |
123 | dem->north_scale = 10.0; | |
70147e60 | 124 | dem->orig_vert_units = VIK_DEM_VERT_DECIMETERS; |
ad0a8c2d EB |
125 | } else { |
126 | dem->east_scale = 3.0; /* arcseconds */ | |
127 | dem->north_scale = 3.0; | |
70147e60 | 128 | dem->orig_vert_units = VIK_DEM_VERT_METERS; |
ad0a8c2d EB |
129 | } |
130 | ||
131 | /* skip next */ | |
132 | get_double_and_continue(&buffer, &val, TRUE); | |
133 | ||
134 | /* now we get the four corner points. record the min and max. */ | |
135 | get_double_and_continue(&buffer, &val, TRUE); | |
136 | dem->min_east = dem->max_east = val; | |
137 | get_double_and_continue(&buffer, &val, TRUE); | |
138 | dem->min_north = dem->max_north = val; | |
139 | ||
140 | for ( i = 0; i < 3; i++ ) { | |
141 | get_double_and_continue(&buffer, &val, TRUE); | |
142 | if ( val < dem->min_east ) dem->min_east = val; | |
143 | if ( val > dem->max_east ) dem->max_east = val; | |
144 | get_double_and_continue(&buffer, &val, TRUE); | |
145 | if ( val < dem->min_north ) dem->min_north = val; | |
146 | if ( val > dem->max_north ) dem->max_north = val; | |
147 | } | |
148 | ||
149 | return TRUE; | |
150 | } | |
151 | ||
152 | static void dem_parse_block_as_cont ( gchar *buffer, VikDEM *dem, gint *cur_column, gint *cur_row ) | |
153 | { | |
154 | gint tmp; | |
155 | while ( *cur_row < GET_COLUMN(dem, *cur_column)->n_points ) { | |
70147e60 EB |
156 | if ( get_int_and_continue(&buffer, &tmp,FALSE) ) { |
157 | if ( dem->orig_vert_units == VIK_DEM_VERT_DECIMETERS ) | |
158 | GET_COLUMN(dem, *cur_column)->points[*cur_row] = (gint16) (tmp / 10); | |
159 | else | |
160 | GET_COLUMN(dem, *cur_column)->points[*cur_row] = (gint16) tmp; | |
161 | } else | |
ad0a8c2d EB |
162 | return; |
163 | (*cur_row)++; | |
164 | } | |
165 | *cur_row = -1; /* expecting new column */ | |
166 | } | |
167 | ||
168 | static void dem_parse_block_as_header ( gchar *buffer, VikDEM *dem, gint *cur_column, gint *cur_row ) | |
169 | { | |
170 | guint n_rows; | |
171 | gint i; | |
172 | gdouble east_west, south; | |
173 | gdouble tmp; | |
174 | ||
175 | /* 1 x n_rows 1 east_west south x x x DATA */ | |
176 | ||
177 | if ( (!get_double_and_continue(&buffer, &tmp, TRUE)) || tmp != 1 ) { | |
4c77d5e0 | 178 | g_warning(_("Incorrect DEM Class B record: expected 1")); |
ad0a8c2d EB |
179 | return; |
180 | } | |
181 | ||
182 | /* don't need this */ | |
183 | if ( !get_double_and_continue(&buffer, &tmp, TRUE ) ) return; | |
184 | ||
185 | /* n_rows */ | |
186 | if ( !get_double_and_continue(&buffer, &tmp, TRUE ) ) | |
187 | return; | |
188 | n_rows = (guint) tmp; | |
189 | ||
190 | if ( (!get_double_and_continue(&buffer, &tmp, TRUE)) || tmp != 1 ) { | |
4c77d5e0 | 191 | g_warning(_("Incorrect DEM Class B record: expected 1")); |
ad0a8c2d EB |
192 | return; |
193 | } | |
194 | ||
195 | if ( !get_double_and_continue(&buffer, &east_west, TRUE) ) | |
196 | return; | |
197 | if ( !get_double_and_continue(&buffer, &south, TRUE) ) | |
198 | return; | |
199 | ||
200 | /* next three things we don't need */ | |
201 | if ( !get_double_and_continue(&buffer, &tmp, TRUE)) return; | |
202 | if ( !get_double_and_continue(&buffer, &tmp, TRUE)) return; | |
203 | if ( !get_double_and_continue(&buffer, &tmp, TRUE)) return; | |
204 | ||
205 | ||
206 | dem->n_columns ++; | |
207 | (*cur_column) ++; | |
208 | ||
209 | /* empty spaces for things before that were skipped */ | |
210 | (*cur_row) = (south - dem->min_north) / dem->north_scale; | |
211 | if ( south > dem->max_north || (*cur_row) < 0 ) | |
212 | (*cur_row) = 0; | |
213 | ||
214 | n_rows += *cur_row; | |
215 | ||
216 | g_ptr_array_add ( dem->columns, g_malloc(sizeof(VikDEMColumn)) ); | |
217 | GET_COLUMN(dem,*cur_column)->east_west = east_west; | |
218 | GET_COLUMN(dem,*cur_column)->south = south; | |
219 | GET_COLUMN(dem,*cur_column)->n_points = n_rows; | |
220 | GET_COLUMN(dem,*cur_column)->points = g_malloc(sizeof(gint16)*n_rows); | |
221 | ||
222 | /* no information for things before that */ | |
223 | for ( i = 0; i < (*cur_row); i++ ) | |
224 | GET_COLUMN(dem,*cur_column)->points[i] = VIK_DEM_INVALID_ELEVATION; | |
225 | ||
226 | /* now just continue */ | |
227 | dem_parse_block_as_cont ( buffer, dem, cur_column, cur_row ); | |
228 | ||
229 | ||
230 | } | |
231 | ||
232 | static void dem_parse_block ( gchar *buffer, VikDEM *dem, gint *cur_column, gint *cur_row ) | |
233 | { | |
234 | /* if haven't read anything or have read all items in a columns and are expecting a new column */ | |
235 | if ( *cur_column == -1 || *cur_row == -1 ) { | |
236 | dem_parse_block_as_header(buffer, dem, cur_column, cur_row); | |
237 | } else { | |
238 | dem_parse_block_as_cont(buffer, dem, cur_column, cur_row); | |
239 | } | |
240 | } | |
241 | ||
46e4fa54 QT |
242 | /* return size of unzip data or 0 if failed */ |
243 | /* can be made generic to uncompress zip, gzip, bzip2 data */ | |
244 | static guint uncompress_data(void *uncompressed_buffer, guint uncompressed_size, void *compressed_data, guint compressed_size) | |
245 | { | |
246 | z_stream stream; | |
247 | int err; | |
248 | ||
249 | stream.next_in = compressed_data; | |
250 | stream.avail_in = compressed_size; | |
251 | stream.next_out = uncompressed_buffer; | |
252 | stream.avail_out = uncompressed_size; | |
253 | stream.zalloc = (alloc_func)0; | |
254 | stream.zfree = (free_func)0; | |
255 | stream.opaque = (voidpf)0; | |
256 | ||
257 | /* negative windowBits to inflateInit2 means "no header" */ | |
258 | if ((err = inflateInit2(&stream, -MAX_WBITS)) != Z_OK) { | |
259 | g_warning("%s(): inflateInit2 failed", __PRETTY_FUNCTION__); | |
260 | return 0; | |
261 | } | |
262 | ||
263 | err = inflate(&stream, Z_FINISH); | |
264 | if ((err != Z_OK) && (err != Z_STREAM_END) && stream.msg) { | |
265 | g_warning("%s() inflate failed err=%d \"%s\"", __PRETTY_FUNCTION__, err, stream.msg == NULL ? "unknown" : stream.msg); | |
266 | inflateEnd(&stream); | |
267 | return 0; | |
268 | } | |
269 | ||
270 | inflateEnd(&stream); | |
271 | return(stream.total_out); | |
272 | } | |
273 | ||
274 | static void *unzip_hgt_file(gchar *zip_file, gulong *unzip_size) | |
275 | { | |
276 | void *unzip_data = NULL; | |
277 | gchar *zip_data; | |
278 | struct _lfh { | |
279 | guint32 sig; | |
280 | guint16 extract_version; | |
281 | guint16 flags; | |
282 | guint16 comp_method; | |
283 | guint16 time; | |
284 | guint16 date; | |
285 | guint32 crc_32; | |
286 | guint32 compressed_size; | |
287 | guint32 uncompressed_size; | |
288 | guint16 filename_len; | |
289 | guint16 extra_field_len; | |
290 | } __attribute__ ((__packed__)) *local_file_header = NULL; | |
291 | ||
292 | ||
293 | local_file_header = (struct _lfh *) zip_file; | |
294 | if (local_file_header->sig != 0x04034b50) { | |
4258f4e2 | 295 | g_warning("%s(): wrong format", __PRETTY_FUNCTION__); |
46e4fa54 QT |
296 | g_free(unzip_data); |
297 | goto end; | |
298 | } | |
299 | ||
300 | zip_data = zip_file + sizeof(struct _lfh) + local_file_header->filename_len + local_file_header->extra_field_len; | |
301 | unzip_data = g_malloc(local_file_header->uncompressed_size); | |
302 | gulong uncompressed_size = local_file_header->uncompressed_size; | |
303 | ||
304 | if (!(*unzip_size = uncompress_data(unzip_data, uncompressed_size, zip_data, local_file_header->compressed_size))) { | |
305 | g_free(unzip_data); | |
306 | unzip_data = NULL; | |
307 | goto end; | |
308 | } | |
309 | ||
310 | end: | |
311 | return(unzip_data); | |
312 | } | |
313 | ||
31766324 | 314 | static VikDEM *vik_dem_read_srtm_hgt(const gchar *file_name, const gchar *basename, gboolean zip) |
ad0a8c2d | 315 | { |
ad0a8c2d EB |
316 | gint i, j; |
317 | VikDEM *dem; | |
46e4fa54 QT |
318 | off_t file_size; |
319 | gint16 *dem_mem = NULL; | |
31766324 | 320 | gchar *dem_file = NULL; |
46e4fa54 QT |
321 | const gint num_rows_3sec = 1201; |
322 | const gint num_rows_1sec = 3601; | |
323 | gint num_rows; | |
31766324 | 324 | GMappedFile *mf; |
46e4fa54 | 325 | gint arcsec; |
a95be497 | 326 | GError *error = NULL; |
ad0a8c2d EB |
327 | |
328 | dem = g_malloc(sizeof(VikDEM)); | |
329 | ||
330 | dem->horiz_units = VIK_DEM_HORIZ_LL_ARCSECONDS; | |
70147e60 | 331 | dem->orig_vert_units = VIK_DEM_VERT_DECIMETERS; |
ad0a8c2d EB |
332 | |
333 | /* TODO */ | |
334 | dem->min_north = atoi(basename+1) * 3600; | |
335 | dem->min_east = atoi(basename+4) * 3600; | |
336 | if ( basename[0] == 'S' ) | |
337 | dem->min_north = - dem->min_north; | |
338 | if ( basename[3] == 'W' ) | |
339 | dem->min_east = - dem->min_east; | |
340 | ||
341 | dem->max_north = 3600 + dem->min_north; | |
342 | dem->max_east = 3600 + dem->min_east; | |
343 | ||
344 | dem->columns = g_ptr_array_new(); | |
345 | dem->n_columns = 0; | |
346 | ||
a95be497 GB |
347 | if ((mf = g_mapped_file_new(file_name, FALSE, &error)) == NULL) { |
348 | g_error(_("Couldn't map file %s: %s"), file_name, error->message); | |
349 | g_error_free(error); | |
31766324 MA |
350 | g_free(dem); |
351 | return NULL; | |
352 | } | |
353 | file_size = g_mapped_file_get_length(mf); | |
354 | dem_file = g_mapped_file_get_contents(mf); | |
355 | ||
46e4fa54 QT |
356 | if (zip) { |
357 | void *unzip_mem = NULL; | |
358 | gulong ucsize; | |
359 | ||
31766324 MA |
360 | if ((unzip_mem = unzip_hgt_file(dem_file, &ucsize)) == NULL) { |
361 | g_mapped_file_free(mf); | |
46e4fa54 QT |
362 | g_ptr_array_free(dem->columns, TRUE); |
363 | g_free(dem); | |
364 | return NULL; | |
365 | } | |
366 | ||
367 | dem_mem = unzip_mem; | |
368 | file_size = ucsize; | |
369 | } | |
370 | ||
371 | if (file_size == (num_rows_3sec * num_rows_3sec * sizeof(gint16))) | |
372 | arcsec = 3; | |
373 | else if (file_size == (num_rows_1sec * num_rows_1sec * sizeof(gint16))) | |
374 | arcsec = 1; | |
375 | else { | |
4258f4e2 | 376 | g_warning("%s(): file %s does not have right size", __PRETTY_FUNCTION__, basename); |
31766324 | 377 | g_mapped_file_free(mf); |
46e4fa54 QT |
378 | g_free(dem); |
379 | return NULL; | |
380 | } | |
381 | ||
382 | num_rows = (arcsec == 3) ? num_rows_3sec : num_rows_1sec; | |
383 | dem->east_scale = dem->north_scale = arcsec; | |
384 | ||
385 | for ( i = 0; i < num_rows; i++ ) { | |
ad0a8c2d EB |
386 | dem->n_columns++; |
387 | g_ptr_array_add ( dem->columns, g_malloc(sizeof(VikDEMColumn)) ); | |
46e4fa54 | 388 | GET_COLUMN(dem,i)->east_west = dem->min_east + arcsec*i; |
ad0a8c2d | 389 | GET_COLUMN(dem,i)->south = dem->min_north; |
46e4fa54 QT |
390 | GET_COLUMN(dem,i)->n_points = num_rows; |
391 | GET_COLUMN(dem,i)->points = g_malloc(sizeof(gint16)*num_rows); | |
ad0a8c2d EB |
392 | } |
393 | ||
46e4fa54 QT |
394 | int ent = 0; |
395 | for ( i = (num_rows - 1); i >= 0; i-- ) { | |
396 | for ( j = 0; j < num_rows; j++ ) { | |
792a7488 QT |
397 | GET_COLUMN(dem,j)->points[i] = GINT16_FROM_BE(dem_mem[ent]); |
398 | ent++; | |
ad0a8c2d EB |
399 | } |
400 | ||
401 | } | |
402 | ||
46e4fa54 QT |
403 | if (zip) |
404 | g_free(dem_mem); | |
31766324 | 405 | g_mapped_file_free(mf); |
ad0a8c2d EB |
406 | return dem; |
407 | } | |
408 | ||
409 | #define IS_SRTM_HGT(fn) (strlen((fn))==11 && (fn)[7]=='.' && (fn)[8]=='h' && (fn)[9]=='g' && (fn)[10]=='t' && ((fn)[0]=='N' || (fn)[0]=='S') && ((fn)[3]=='E' || (fn)[3]=='W')) | |
410 | ||
411 | VikDEM *vik_dem_new_from_file(const gchar *file) | |
412 | { | |
31766324 | 413 | FILE *f=NULL; |
ad0a8c2d EB |
414 | VikDEM *rv; |
415 | gchar buffer[DEM_BLOCK_SIZE+1]; | |
416 | ||
417 | /* use to record state for dem_parse_block */ | |
418 | gint cur_column = -1; | |
419 | gint cur_row = -1; | |
420 | const gchar *basename = a_file_basename(file); | |
421 | ||
31766324 | 422 | if ( g_access ( file, R_OK ) != 0 ) |
ad0a8c2d EB |
423 | return NULL; |
424 | ||
46e4fa54 QT |
425 | if ( (strlen(basename)==11 || ((strlen(basename) == 15) && (basename[11] == '.' && basename[12] == 'z' && basename[13] == 'i' && basename[14] == 'p'))) && |
426 | basename[7]=='.' && basename[8]=='h' && basename[9]=='g' && basename[10]=='t' && | |
2dc9ab5e | 427 | (basename[0] == 'N' || basename[0] == 'S') && (basename[3] == 'E' || basename[3] =='W')) { |
46e4fa54 | 428 | gboolean is_zip_file = (strlen(basename) == 15); |
31766324 | 429 | rv = vik_dem_read_srtm_hgt(file, basename, is_zip_file); |
2dc9ab5e QT |
430 | return(rv); |
431 | } | |
ad0a8c2d EB |
432 | |
433 | /* Create Structure */ | |
434 | rv = g_malloc(sizeof(VikDEM)); | |
435 | ||
436 | /* Header */ | |
31766324 MA |
437 | f = g_fopen(file, "r"); |
438 | if ( !f ) | |
439 | return NULL; | |
ad0a8c2d EB |
440 | buffer[fread(buffer, 1, DEM_BLOCK_SIZE, f)] = '\0'; |
441 | if ( ! dem_parse_header ( buffer, rv ) ) { | |
442 | g_free ( rv ); | |
443 | return NULL; | |
444 | } | |
445 | /* TODO: actually use header -- i.e. GET # OF COLUMNS EXPECTED */ | |
446 | ||
447 | rv->columns = g_ptr_array_new(); | |
448 | rv->n_columns = 0; | |
449 | ||
450 | /* Column -- Data */ | |
451 | while (! feof(f) ) { | |
452 | gchar *tmp; | |
453 | ||
454 | /* read block */ | |
455 | buffer[fread(buffer, 1, DEM_BLOCK_SIZE, f)] = '\0'; | |
456 | ||
457 | /* Fix Fortran-style exponentiation */ | |
458 | tmp = buffer; | |
459 | while (*tmp) { | |
460 | if ( *tmp=='D') | |
461 | *tmp='E'; | |
462 | tmp++; | |
463 | } | |
464 | ||
465 | dem_parse_block(buffer, rv, &cur_column, &cur_row); | |
466 | } | |
467 | ||
468 | /* TODO - class C records (right now says 'Invalid' and dies) */ | |
469 | ||
470 | fclose(f); | |
8c060406 | 471 | f = NULL; |
ad0a8c2d EB |
472 | |
473 | /* 24k scale */ | |
474 | if ( rv->horiz_units == VIK_DEM_HORIZ_UTM_METERS && rv->n_columns >= 2 ) | |
475 | rv->north_scale = rv->east_scale = GET_COLUMN(rv, 1)->east_west - GET_COLUMN(rv,0)->east_west; | |
476 | ||
477 | /* FIXME bug in 10m DEM's */ | |
478 | if ( rv->horiz_units == VIK_DEM_HORIZ_UTM_METERS && rv->north_scale == 10 ) { | |
479 | rv->min_east -= 100; | |
480 | rv->min_north += 200; | |
481 | } | |
482 | ||
483 | ||
484 | return rv; | |
485 | } | |
486 | ||
487 | void vik_dem_free ( VikDEM *dem ) | |
488 | { | |
489 | guint i; | |
490 | for ( i = 0; i < dem->n_columns; i++) | |
491 | g_free ( GET_COLUMN(dem, i)->points ); | |
492 | g_ptr_array_free ( dem->columns, TRUE ); | |
493 | g_free ( dem ); | |
494 | } | |
495 | ||
496 | gint16 vik_dem_get_xy ( VikDEM *dem, guint col, guint row ) | |
497 | { | |
498 | if ( col < dem->n_columns ) | |
499 | if ( row < GET_COLUMN(dem, col)->n_points ) | |
500 | return GET_COLUMN(dem, col)->points[row]; | |
501 | return VIK_DEM_INVALID_ELEVATION; | |
502 | } | |
503 | ||
504 | gint16 vik_dem_get_east_north ( VikDEM *dem, gdouble east, gdouble north ) | |
505 | { | |
506 | gint col, row; | |
507 | ||
508 | if ( east > dem->max_east || east < dem->min_east || | |
509 | north > dem->max_north || north < dem->min_north ) | |
510 | return VIK_DEM_INVALID_ELEVATION; | |
511 | ||
512 | col = (gint) floor((east - dem->min_east) / dem->east_scale); | |
513 | row = (gint) floor((north - dem->min_north) / dem->north_scale); | |
514 | ||
515 | return vik_dem_get_xy ( dem, col, row ); | |
516 | } | |
517 | ||
5ef1d57e QT |
518 | static gboolean dem_get_ref_points_elev_dist(VikDEM *dem, |
519 | gdouble east, gdouble north, /* in seconds */ | |
520 | gint16 *elevs, gint16 *dists) | |
521 | { | |
522 | int i; | |
523 | int cols[4], rows[4]; | |
524 | struct LatLon ll[4]; | |
525 | struct LatLon pos; | |
526 | ||
527 | if ( east > dem->max_east || east < dem->min_east || | |
528 | north > dem->max_north || north < dem->min_north ) | |
529 | return FALSE; /* got nothing */ | |
530 | ||
531 | pos.lon = east/3600; | |
532 | pos.lat = north/3600; | |
533 | ||
534 | /* order of the data: sw, nw, ne, se */ | |
245575e1 QT |
535 | /* sw */ |
536 | cols[0] = (gint) floor((east - dem->min_east) / dem->east_scale); | |
5ef1d57e | 537 | rows[0] = (gint) floor((north - dem->min_north) / dem->north_scale); |
228213c5 QT |
538 | ll[0].lon = (dem->min_east + dem->east_scale*cols[0])/3600; |
539 | ll[0].lat = (dem->min_north + dem->north_scale*rows[0])/3600; | |
245575e1 QT |
540 | /* nw */ |
541 | cols[1] = cols[0]; | |
5ef1d57e QT |
542 | rows[1] = rows[0] + 1; |
543 | ll[1].lon = ll[0].lon; | |
544 | ll[1].lat = ll[0].lat + (gdouble)dem->north_scale/3600; | |
245575e1 QT |
545 | /* ne */ |
546 | cols[2] = cols[0] + 1; | |
5ef1d57e QT |
547 | rows[2] = rows[0] + 1; |
548 | ll[2].lon = ll[0].lon + (gdouble)dem->east_scale/3600; | |
549 | ll[2].lat = ll[0].lat + (gdouble)dem->north_scale/3600; | |
245575e1 QT |
550 | /* se */ |
551 | cols[3] = cols[0] + 1; | |
5ef1d57e QT |
552 | rows[3] = rows[0]; |
553 | ll[3].lon = ll[0].lon + (gdouble)dem->east_scale/3600; | |
554 | ll[3].lat = ll[0].lat; | |
555 | ||
556 | for (i = 0; i < 4; i++) { | |
557 | if ((elevs[i] = vik_dem_get_xy(dem, cols[i], rows[i])) == VIK_DEM_INVALID_ELEVATION) | |
558 | return FALSE; | |
559 | dists[i] = a_coords_latlon_diff(&pos, &ll[i]); | |
560 | } | |
561 | ||
228213c5 QT |
562 | #if 0 /* debug */ |
563 | for (i = 0; i < 4; i++) | |
564 | fprintf(stderr, "%f:%f:%d:%d ", ll[i].lat, ll[i].lon, dists[i], elevs[i]); | |
565 | fprintf(stderr, " north_scale=%f\n", dem->north_scale); | |
566 | #endif | |
567 | ||
5ef1d57e QT |
568 | return TRUE; /* all OK */ |
569 | } | |
570 | ||
571 | gint16 vik_dem_get_simple_interpol ( VikDEM *dem, gdouble east, gdouble north ) | |
572 | { | |
573 | int i; | |
574 | gint16 elevs[4], dists[4]; | |
575 | ||
576 | if (!dem_get_ref_points_elev_dist(dem, east, north, elevs, dists)) | |
577 | return VIK_DEM_INVALID_ELEVATION; | |
578 | ||
579 | for (i = 0; i < 4; i++) { | |
580 | if (dists[i] < 1) { | |
581 | return(elevs[i]); | |
582 | } | |
583 | } | |
584 | ||
585 | gdouble t = (gdouble)elevs[0]/dists[0] + (gdouble)elevs[1]/dists[1] + (gdouble)elevs[2]/dists[2] + (gdouble)elevs[3]/dists[3]; | |
586 | gdouble b = 1.0/dists[0] + 1.0/dists[1] + 1.0/dists[2] + 1.0/dists[3]; | |
587 | ||
588 | return(t/b); | |
589 | } | |
590 | ||
591 | gint16 vik_dem_get_shepard_interpol ( VikDEM *dem, gdouble east, gdouble north ) | |
592 | { | |
228213c5 QT |
593 | int i; |
594 | gint16 elevs[4], dists[4]; | |
595 | gint16 max_dist; | |
596 | gdouble t = 0.0; | |
597 | gdouble b = 0.0; | |
598 | ||
599 | if (!dem_get_ref_points_elev_dist(dem, east, north, elevs, dists)) | |
600 | return VIK_DEM_INVALID_ELEVATION; | |
601 | ||
602 | max_dist = 0; | |
603 | for (i = 0; i < 4; i++) { | |
604 | if (dists[i] < 1) { | |
605 | return(elevs[i]); | |
606 | } | |
607 | if (dists[i] > max_dist) | |
608 | max_dist = dists[i]; | |
609 | } | |
610 | ||
611 | gdouble tmp; | |
612 | #if 0 /* derived method by Franke & Nielson. Does not seem to work too well here */ | |
613 | for (i = 0; i < 4; i++) { | |
614 | tmp = pow((1.0*(max_dist - dists[i])/max_dist*dists[i]), 2); | |
615 | t += tmp*elevs[i]; | |
616 | b += tmp; | |
617 | } | |
618 | #endif | |
619 | ||
620 | for (i = 0; i < 4; i++) { | |
621 | tmp = pow((1.0/dists[i]), 2); | |
622 | t += tmp*elevs[i]; | |
623 | b += tmp; | |
624 | } | |
625 | ||
626 | // fprintf(stderr, "DEBUG: tmp=%f t=%f b=%f %f\n", tmp, t, b, t/b); | |
627 | ||
628 | return(t/b); | |
629 | ||
5ef1d57e QT |
630 | } |
631 | ||
ad0a8c2d EB |
632 | void vik_dem_east_north_to_xy ( VikDEM *dem, gdouble east, gdouble north, guint *col, guint *row ) |
633 | { | |
634 | *col = (gint) floor((east - dem->min_east) / dem->east_scale); | |
635 | *row = (gint) floor((north - dem->min_north) / dem->north_scale); | |
636 | if ( *col < 0 ) *col = 0; | |
637 | if ( *row < 0 ) *row = 0; | |
638 | } | |
639 |