GRASS GIS 7 Programmer's Manual  7.9.dev(2021)-e5379bbd7
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 googlemail.com> (2012)
14  */
15 
16 #include <string.h>
17 
18 #include <grass/gis.h>
19 #include <grass/glocale.h>
20 
21 /*!
22  \brief Units conversion from meters to units
23 
24  Units codes (gis.h):
25  - U_METERS
26  - U_KILOMETERS
27  - U_MILES
28  - U_FEET
29  - U_USFEET
30 
31  Returns a factor which converts meters to units (by multiplication).
32 
33  \param units units code
34 
35  \return factor
36 */
37 double G_meters_to_units_factor(int units)
38 {
39  switch (units) {
40  case U_METERS:
41  return 1.0;
42  break;
43 
44  case U_KILOMETERS:
45  return 1.0e-3;
46  break;
47 
48  case U_MILES:
49  return 6.21371192237334e-4; /* 1 / (0.0254 * 12 * 5280) */
50  break;
51 
52  case U_FEET:
53  return 3.28083989501312; /* 1 / (0.0254 * 12) */
54  break;
55 
56  case U_USFEET:
57  return 3.28083333333333; /* 1 / (1200/3937) */
58  break;
59 
60  default:
61  return 1.0;
62  break;
63  }
64 
65  return 1.0;
66 }
67 
68 /*!
69  \brief Units conversion from square meters to square units
70 
71  Units codes (gis.h):
72  - U_METERS
73  - U_KILOMETERS
74  - U_ACRES
75  - U_HECTARES
76  - U_MILES
77  - U_FEET
78  - U_USFEET
79 
80  Returns a factor which converts square meters to square units (by
81  multiplication).
82 
83  \param units units code
84 
85  \return factor
86 */
87 double G_meters_to_units_factor_sq(int units)
88 {
89  switch (units) {
90  case U_METERS:
91  return 1.0;
92  break;
93 
94  case U_KILOMETERS:
95  return 1.0e-6;
96  break;
97 
98  case U_ACRES:
99  return 2.47105381467165e-4; /* 640 acres in a sq mile */
100  break;
101 
102  case U_HECTARES:
103  return 1.0e-4;
104  break;
105 
106  case U_MILES:
107  return 3.86102158542446e-7; /* 1 / (0.0254 * 12 * 5280)^2 */
108  break;
109 
110  case U_FEET:
111  return 10.7639104167097; /* 1 / (0.0254 * 12)^2 */
112  break;
113 
114  case U_USFEET:
115  return 10.7638673611111; /* 1 / (1200/3937)^2 */
116  break;
117 
118  default:
119  return 1.0;
120  break;
121  }
122 
123  return 1.0;
124 }
125 
126 /** \brief Check if the unit is of spatial type
127 
128  \param units units code from gis.h
129 
130  \return 1 if True, 0 otherwise
131  */
132 
133 int 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  */
164 
165 int G_is_units_type_temporal(int units)
166 {
167  switch (units) {
168  case U_YEARS:
169  return 1;
170  case U_MONTHS:
171  return 1;
172  case U_DAYS:
173  return 1;
174  case U_HOURS:
175  return 1;
176  case U_MINUTES:
177  return 1;
178  case U_SECONDS:
179  return 1;
180  }
181  return 0;
182 }
183 
184 /*!
185  \brief Get localized units name
186 
187  Units codes (gis.h):
188  - U_METERS
189  - U_KILOMETERS
190  - U_ACRES
191  - U_HECTARES
192  - U_MILES
193  - U_FEET
194  - U_USFEET
195 
196  \param units units code
197  \param plural plural form if true
198  \param square area units if true
199 
200  \return units name
201  \return NULL if units not found
202 */
203 const char *G_get_units_name(int units, int plural, int square)
204 {
205  switch (units) {
206  case U_UNKNOWN:
207  if (square)
208  return plural ? _("square units") : _("square unit");
209  else
210  return plural ? _("units") : _("unit");
211  break;
212 
213  case U_METERS:
214  if (square)
215  return plural ? _("square meters") : _("square meter");
216  else
217  return plural ? _("meters") : _("meter");
218  break;
219 
220  case U_KILOMETERS:
221  if (square)
222  return plural ? _("square kilometers") : _("square kilometer");
223  else
224  return plural ? _("kilometers") : _("kilometer");
225  break;
226 
227  case U_ACRES:
228  if (square)
229  return plural ? _("acres") : _("acre");
230  else
231  return G_get_units_name(G_units(G_database_unit_name(1)),
232  plural, square);
233  break;
234 
235  case U_HECTARES:
236  if (square)
237  return plural ? _("hectares") : _("hectare");
238  else
239  return G_get_units_name(G_units(G_database_unit_name(1)),
240  plural, square);
241  break;
242 
243  case U_MILES:
244  if (square)
245  return plural ? _("square miles") : _("square mile");
246  else
247  return plural ? _("miles") : _("mile");
248  break;
249 
250  case U_FEET:
251  if (square)
252  return plural ? _("square feet") : _("square foot");
253  else
254  return plural ? _("feet") : _("foot");
255  break;
256 
257  case U_USFEET:
258  if (square)
259  return plural ? _("square US feet") : _("square US foot");
260  else
261  return plural ? _("US feet") : _("US foot");
262  break;
263 
264  case U_DEGREES:
265  if (square)
266  return plural ? _("square degrees") : _("square degree");
267  else
268  return plural ? _("degrees") : _("degree");
269  break;
270 
271  case U_YEARS:
272  return plural ? _("years") : _("year");
273  break;
274 
275  case U_MONTHS:
276  return plural ? _("months") : _("month");
277  break;
278 
279  case U_DAYS:
280  return plural ? _("days") : _("day");
281  break;
282 
283  case U_HOURS:
284  return plural ? _("hours") : _("hour");
285  break;
286 
287  case U_MINUTES:
288  return plural ? _("minutes") : _("minute");
289  break;
290 
291  case U_SECONDS:
292  return plural ? _("seconds") : _("second");
293  break;
294  }
295 
296  return NULL;
297 }
298 
299 /*!
300  \brief Get units code by name
301 
302  Units codes (gis.h):
303  - U_METERS
304  - U_KILOMETERS
305  - U_ACRES
306  - U_HECTARES
307  - U_MILES
308  - U_FEET
309  - U_USFEET
310  - ...
311  - U_YEARS
312  - ...
313 
314  \param units_name units name (singular or plural form)
315 
316  \return units code
317  \return U_UNKNOWN if not found
318 */
319 int G_units(const char *units_name)
320 {
321  if (units_name == NULL) {
322  return G_units(G_database_unit_name(1));
323  }
324 
325  if (strcasecmp(units_name, "meter") == 0 ||
326  strcasecmp(units_name, "meters") == 0)
327  return U_METERS;
328  else if (strcasecmp(units_name, "kilometer") == 0 ||
329  strcasecmp(units_name, "kilometers") == 0)
330  return U_KILOMETERS;
331  else if (strcasecmp(units_name, "acre") == 0 ||
332  strcasecmp(units_name, "acres") == 0)
333  return U_ACRES;
334  else if (strcasecmp(units_name, "hectare") == 0 ||
335  strcasecmp(units_name, "hectares") == 0)
336  return U_HECTARES;
337  else if (strcasecmp(units_name, "mile") == 0 ||
338  strcasecmp(units_name, "miles") == 0)
339  return U_MILES;
340  else if (strcasecmp(units_name, "foot") == 0 ||
341  strcasecmp(units_name, "feet") == 0)
342  return U_FEET;
343  else if (strcasecmp(units_name, "foot_us") == 0 ||
344  strcasecmp(units_name, "foot_uss") == 0)
345  return U_USFEET;
346  else if (strcasecmp(units_name, "degree") == 0 ||
347  strcasecmp(units_name, "degrees") == 0)
348  return U_DEGREES;
349  else if (strcasecmp(units_name, "year") == 0 ||
350  strcasecmp(units_name, "years") == 0)
351  return U_YEARS;
352  else if (strcasecmp(units_name, "month") == 0 ||
353  strcasecmp(units_name, "months") == 0)
354  return U_MONTHS;
355  else if (strcasecmp(units_name, "day") == 0 ||
356  strcasecmp(units_name, "days") == 0)
357  return U_DAYS;
358  else if (strcasecmp(units_name, "hour") == 0 ||
359  strcasecmp(units_name, "hours") == 0)
360  return U_HOURS;
361  else if (strcasecmp(units_name, "minute") == 0 ||
362  strcasecmp(units_name, "minutes") == 0)
363  return U_MINUTES;
364  else if (strcasecmp(units_name, "secons") == 0 ||
365  strcasecmp(units_name, "seconds") == 0)
366  return U_SECONDS;
367 
368  return U_UNKNOWN;
369 }
U_HECTARES
#define U_HECTARES
Definition: gis.h:93
U_FEET
#define U_FEET
Definition: gis.h:97
U_MILES
#define U_MILES
Definition: gis.h:96
U_RADIANS
#define U_RADIANS
Definition: gis.h:98
U_METERS
#define U_METERS
Definition: gis.h:95
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:87
U_YEARS
#define U_YEARS
Definition: gis.h:102
U_DEGREES
#define U_DEGREES
Definition: gis.h:99
NULL
#define NULL
Definition: ccmath.h:32
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
U_HOURS
#define U_HOURS
Definition: gis.h:105
U_KILOMETERS
#define U_KILOMETERS
Definition: gis.h:94
U_MINUTES
#define U_MINUTES
Definition: gis.h:106
G_units
int G_units(const char *units_name)
Get units code by name.
Definition: units.c:319
U_UNKNOWN
#define U_UNKNOWN
Definition: gis.h:91
U_SECONDS
#define U_SECONDS
Definition: gis.h:107
U_USFEET
#define U_USFEET
Definition: gis.h:100
G_is_units_type_temporal
int G_is_units_type_temporal(int units)
Check if the unit is of temporal type.
Definition: units.c:165
U_DAYS
#define U_DAYS
Definition: gis.h:104
U_ACRES
#define U_ACRES
Definition: gis.h:92
G_meters_to_units_factor
double G_meters_to_units_factor(int units)
Units conversion from meters to units.
Definition: units.c:37
_
#define _(str)
Definition: glocale.h:10
G_get_units_name
const char * G_get_units_name(int units, int plural, int square)
Get localized units name.
Definition: units.c:203
G_database_unit_name
const char * G_database_unit_name(int)
Get units (localized) name for the current location.
Definition: proj3.c:53
U_MONTHS
#define U_MONTHS
Definition: gis.h:103