GRASS 8 Programmer's Manual 8.6.0dev(2026)-1d1e47ad9d
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units.c
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1/*!
2 \file lib/gis/units.c
3
4 \brief GIS Library - Units management and conversion
5
6 (C) 2001-2010 by the GRASS Development Team
7
8 This program is free software under the GNU General Public License
9 (>=v2). Read the file COPYING that comes with GRASS for details.
10
11 \author Original author CERL
12 \author Adopted for libgis by Martin Landa <landa.martin gmail.com> (2010)
13 \author Temporal units and unit type check from Soeren gebbert <soerengebbert
14 googlemail.com> (2012)
15 */
16
17#include <string.h>
18
19#include <grass/gis.h>
20#include <grass/glocale.h>
21
22/*!
23 \brief Units conversion from meters to units
24
25 Units codes (gis.h):
26 - U_METERS
27 - U_KILOMETERS
28 - U_MILES
29 - U_FEET
30 - U_USFEET
31
32 Returns a factor which converts meters to units (by multiplication).
33
34 \param units units code
35
36 \return factor
37 */
38double G_meters_to_units_factor(int units)
39{
40 switch (units) {
41 case U_METERS:
42 return 1.0;
43 break;
44
45 case U_KILOMETERS:
46 return 1.0e-3;
47 break;
48
49 case U_MILES:
50 return 6.21371192237334e-4; /* 1 / (0.0254 * 12 * 5280) */
51 break;
52
53 case U_FEET:
54 return 3.28083989501312; /* 1 / (0.0254 * 12) */
55 break;
56
57 case U_USFEET:
58 return 3.28083333333333; /* 1 / (1200/3937) */
59 break;
60
61 default:
62 return 1.0;
63 break;
64 }
65
66 return 1.0;
67}
68
69/*!
70 \brief Units conversion from square meters to square units
71
72 Units codes (gis.h):
73 - U_METERS
74 - U_KILOMETERS
75 - U_ACRES
76 - U_HECTARES
77 - U_MILES
78 - U_FEET
79 - U_USFEET
80
81 Returns a factor which converts square meters to square units (by
82 multiplication).
83
84 \param units units code
85
86 \return factor
87 */
88double G_meters_to_units_factor_sq(int units)
89{
90 switch (units) {
91 case U_METERS:
92 return 1.0;
93 break;
94
95 case U_KILOMETERS:
96 return 1.0e-6;
97 break;
98
99 case U_ACRES:
100 return 2.47105381467165e-4; /* 640 acres in a sq mile */
101 break;
102
103 case U_HECTARES:
104 return 1.0e-4;
105 break;
106
107 case U_MILES:
108 return 3.86102158542446e-7; /* 1 / (0.0254 * 12 * 5280)^2 */
109 break;
110
111 case U_FEET:
112 return 10.7639104167097; /* 1 / (0.0254 * 12)^2 */
113 break;
114
115 case U_USFEET:
116 return 10.7638673611111; /* 1 / (1200/3937)^2 */
117 break;
118
119 default:
120 return 1.0;
121 break;
122 }
123
124 return 1.0;
125}
126
127/** \brief Check if the unit is of spatial type
128
129 \param units units code from gis.h
130
131 \return 1 if True, 0 otherwise
132 */
133int G_is_units_type_spatial(int units)
134{
135 switch (units) {
136 case U_METERS:
137 return 1;
138 case U_KILOMETERS:
139 return 1;
140 case U_HECTARES:
141 return 1;
142 case U_ACRES:
143 return 1;
144 case U_MILES:
145 return 1;
146 case U_FEET:
147 return 1;
148 case U_USFEET:
149 return 1;
150 case U_RADIANS:
151 return 1;
152 case U_DEGREES:
153 return 1;
154 }
155 return 0;
156}
157
158/** \brief Check if the unit is of temporal type
159
160 \param units units code from gis.h
161
162 \return 1 if True, 0 otherwise
163 */
164int G_is_units_type_temporal(int units)
165{
166 switch (units) {
167 case U_YEARS:
168 return 1;
169 case U_MONTHS:
170 return 1;
171 case U_DAYS:
172 return 1;
173 case U_HOURS:
174 return 1;
175 case U_MINUTES:
176 return 1;
177 case U_SECONDS:
178 return 1;
179 }
180 return 0;
181}
182
183/*!
184 \brief Get localized units name
185
186 Units codes (gis.h):
187 - U_METERS
188 - U_KILOMETERS
189 - U_ACRES
190 - U_HECTARES
191 - U_MILES
192 - U_FEET
193 - U_USFEET
194
195 \param units units code
196 \param plural plural form if true
197 \param square area units if true
198
199 \return units name
200 \return NULL if units not found
201 */
202const char *G_get_units_name(int units, int plural, int square)
203{
204 switch (units) {
205 case U_UNKNOWN:
206 if (square)
207 return plural
208 // GTC: localized area units
209 ? _("square units")
210 // GTC: localized area units
211 : _("square unit");
212 else
213 return plural
214 // GTC: localized units
215 ? _("units")
216 // GTC: localized units
217 : _("unit");
218 break;
219
220 case U_METERS:
221 if (square)
222 return plural
223 // GTC: localized area units
224 ? _("square meters")
225 // GTC: localized area units
226 : _("square meter");
227 else
228 return plural
229 // GTC: localized units
230 ? _("meters")
231 // GTC: localized units
232 : _("meter");
233 break;
234
235 case U_KILOMETERS:
236 if (square)
237 return plural
238 // GTC: localized area units
239 ? _("square kilometers")
240 // GTC: localized area units
241 : _("square kilometer");
242 else
243 return plural
244 // GTC: localized units
245 ? _("kilometers")
246 // GTC: localized units
247 : _("kilometer");
248 break;
249
250 case U_ACRES:
251 if (square)
252 return plural
253 // GTC: localized area units
254 ? _("acres")
255 // GTC: localized area units
256 : _("acre");
257 else
258 return G_get_units_name(G_units(G_database_unit_name(1)), plural,
259 square);
260 break;
261
262 case U_HECTARES:
263 if (square)
264 return plural
265 // GTC: localized area units
266 ? _("hectares")
267 // GTC: localized area units
268 : _("hectare");
269 else
270 return G_get_units_name(G_units(G_database_unit_name(1)), plural,
271 square);
272 break;
273
274 case U_MILES:
275 if (square)
276 return plural
277 // GTC: localized area units
278 ? _("square miles")
279 // GTC: localized area units
280 : _("square mile");
281 else
282 return plural
283 // GTC: localized units
284 ? _("miles")
285 // GTC: localized units
286 : _("mile");
287 break;
288
289 case U_FEET:
290 if (square)
291 return plural
292 // GTC: localized area units, do not confuse with US feet
293 ? _("square feet")
294 // GTC: localized area units, do not confuse with US foot
295 : _("square foot");
296 else
297 return plural
298 // GTC: localized units, do not confuse with US feet
299 ? _("feet")
300 // GTC: localized units, do not confuse with US foot
301 : _("foot");
302 break;
303
304 case U_USFEET:
305 if (square)
306 return plural
307 // GTC: localized area units, do not confuse with feet
308 ? _("square US feet")
309 // GTC: localized area units, do not confuse with foot
310 : _("square US foot");
311 else
312 return plural
313 // GTC: localized units, do not confuse with feet
314 ? _("US feet")
315 // GTC: localized units, do not confuse with foot
316 : _("US foot");
317 break;
318
319 case U_DEGREES:
320 if (square)
321 return plural
322 // GTC: localized area units
323 ? _("square degrees")
324 // GTC: localized area units
325 : _("square degree");
326 else
327 return plural
328 // GTC: localized units
329 ? _("degrees")
330 // GTC: localized units
331 : _("degree");
332 break;
333
334 case U_YEARS:
335 return plural
336 // GTC: localized time units
337 ? _("years")
338 // GTC: localized time units
339 : _("year");
340 break;
341
342 case U_MONTHS:
343 return plural
344 // GTC: localized time units
345 ? _("months")
346 // GTC: localized time units
347 : _("month");
348 break;
349
350 case U_DAYS:
351 return plural
352 // GTC: localized time units
353 ? _("days")
354 // GTC: localized time units
355 : _("day");
356 break;
357
358 case U_HOURS:
359 return plural
360 // GTC: localized time units
361 ? _("hours")
362 // GTC: localized time units
363 : _("hour");
364 break;
365
366 case U_MINUTES:
367 return plural
368 // GTC: localized time units
369 ? _("minutes")
370 // GTC: localized time units
371 : _("minute");
372 break;
373
374 case U_SECONDS:
375 return plural
376 // GTC: localized time units
377 ? _("seconds")
378 // GTC: localized time units
379 : _("second");
380 break;
381 }
382
383 return NULL;
384}
385
386/*!
387 \brief Get units code by name
388
389 Units codes (gis.h):
390 - U_METERS
391 - U_KILOMETERS
392 - U_ACRES
393 - U_HECTARES
394 - U_MILES
395 - U_FEET
396 - U_USFEET
397 - ...
398 - U_YEARS
399 - ...
400
401 \param units_name units name (singular or plural form)
402
403 \return units code
404 \return U_UNKNOWN if not found
405 */
406int G_units(const char *units_name)
407{
408 if (units_name == NULL) {
409 return G_units(G_database_unit_name(1));
410 }
411
412 if (strcasecmp(units_name, "meter") == 0 ||
413 strcasecmp(units_name, "meters") == 0)
414 return U_METERS;
415 else if (strcasecmp(units_name, "kilometer") == 0 ||
416 strcasecmp(units_name, "kilometers") == 0)
417 return U_KILOMETERS;
418 else if (strcasecmp(units_name, "acre") == 0 ||
419 strcasecmp(units_name, "acres") == 0)
420 return U_ACRES;
421 else if (strcasecmp(units_name, "hectare") == 0 ||
422 strcasecmp(units_name, "hectares") == 0)
423 return U_HECTARES;
424 else if (strcasecmp(units_name, "mile") == 0 ||
425 strcasecmp(units_name, "miles") == 0)
426 return U_MILES;
427 else if (strcasecmp(units_name, "foot") == 0 ||
428 strcasecmp(units_name, "feet") == 0)
429 return U_FEET;
430 else if (strcasecmp(units_name, "foot_us") == 0 ||
431 strcasecmp(units_name, "foot_uss") == 0)
432 return U_USFEET;
433 else if (strcasecmp(units_name, "degree") == 0 ||
434 strcasecmp(units_name, "degrees") == 0)
435 return U_DEGREES;
436 else if (strcasecmp(units_name, "year") == 0 ||
437 strcasecmp(units_name, "years") == 0)
438 return U_YEARS;
439 else if (strcasecmp(units_name, "month") == 0 ||
440 strcasecmp(units_name, "months") == 0)
441 return U_MONTHS;
442 else if (strcasecmp(units_name, "day") == 0 ||
443 strcasecmp(units_name, "days") == 0)
444 return U_DAYS;
445 else if (strcasecmp(units_name, "hour") == 0 ||
446 strcasecmp(units_name, "hours") == 0)
447 return U_HOURS;
448 else if (strcasecmp(units_name, "minute") == 0 ||
449 strcasecmp(units_name, "minutes") == 0)
450 return U_MINUTES;
451 else if (strcasecmp(units_name, "second") == 0 ||
452 strcasecmp(units_name, "seconds") == 0)
453 return U_SECONDS;
454
455 return U_UNKNOWN;
456}
NULL
#define NULL
Definition ccmath.h:32
AMI_STREAM
Definition ami_stream.h:153
G_database_unit_name
const char * G_database_unit_name(int)
Get units (localized) name for the current location.
Definition proj3.c:53
U_SECONDS
#define U_SECONDS
Definition gis.h:120
U_HOURS
#define U_HOURS
Definition gis.h:118
U_MINUTES
#define U_MINUTES
Definition gis.h:119
U_DAYS
#define U_DAYS
Definition gis.h:117
U_FEET
#define U_FEET
Definition gis.h:110
U_ACRES
#define U_ACRES
Definition gis.h:105
U_MONTHS
#define U_MONTHS
Definition gis.h:116
U_RADIANS
#define U_RADIANS
Definition gis.h:111
U_METERS
#define U_METERS
Definition gis.h:108
U_DEGREES
#define U_DEGREES
Definition gis.h:112
U_YEARS
#define U_YEARS
Definition gis.h:115
U_UNKNOWN
#define U_UNKNOWN
Definition gis.h:104
U_HECTARES
#define U_HECTARES
Definition gis.h:106
U_USFEET
#define U_USFEET
Definition gis.h:113
U_MILES
#define U_MILES
Definition gis.h:109
U_KILOMETERS
#define U_KILOMETERS
Definition gis.h:107
_
#define _(str)
Definition glocale.h:10
strcasecmp
#define strcasecmp
Definition strings.h:8
G_meters_to_units_factor
double G_meters_to_units_factor(int units)
Units conversion from meters to units.
Definition units.c:38
G_meters_to_units_factor_sq
double G_meters_to_units_factor_sq(int units)
Units conversion from square meters to square units.
Definition units.c:88
G_get_units_name
const char * G_get_units_name(int units, int plural, int square)
Get localized units name.
Definition units.c:202
G_is_units_type_spatial
int G_is_units_type_spatial(int units)
Check if the unit is of spatial type.
Definition units.c:133
G_is_units_type_temporal
int G_is_units_type_temporal(int units)
Check if the unit is of temporal type.
Definition units.c:164
G_units
int G_units(const char *units_name)
Get units code by name.
Definition units.c:406