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74<a href="ll_narcs_distances.html">&lt;&lt;prev file</a> | <a href="neighbor.html">next file &gt;&gt;</a>&nbsp;&nbsp;&nbsp;&nbsp;<a href="map_npoints.html" target="_TOP">view single page</a> | <a href="./../index.html" target="_TOP">view frames</a>&nbsp;&nbsp;&nbsp;&nbsp;summary: fields | routine&nbsp;&nbsp;&nbsp;&nbsp;details: <a href="#routine_details">routine</a>
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81      <h1 class="directory"><a href="directory-overview.html">Interpolation/</a></h1>
82      <h2 class="pro_file">map_npoints.pro</h2>
83
84      <div id="file_attr">
85        <dl>
86        </dl>
87      </div>
88
89      <div id="file_comments">
90 Return the distance in meter between all np0 points P0 and all
91 np1 points P1 on a sphere. If keyword /TWO_BY_TWO is given then
92 returns the distances between number n of P0 points and number
93 n of P1 points (in that case, np0 and np1 must be equal).
94 Same as <a href="/Applications/itt/idl64/help/online_help/MAP_2POINTS.html">MAP_2POINTS</a> with the meter parameter but for n
95 points without do loop.
96</div>
97
98     
99
100     
101
102     
103
104     
105
106      <div id="routine_details">
107       
108
109        <div class="routine_details" id="_map_npoints">
110
111          <h2><a class="top" href="#container">top</a>map_npoints <span class="categories">
112 Maps
113</span></h2>
114       
115          <p class="header">
116            <span class="result">result = </span>map_npoints(<span class="result"><a href="#_map_npoints_param_lon0">lon0</a>, <a href="#_map_npoints_param_lat0">lat0</a>, <a href="#_map_npoints_param_lon1">lon1</a>, <a href="#_map_npoints_param_lat1">lat1</a></span>, <a href="#_map_npoints_keyword_AZIMUTH">AZIMUTH</a>=<span class="result">AZIMUTH</span>, <a href="#_map_npoints_keyword_RADIANS">RADIANS</a>=<span class="result">RADIANS</span>, <a href="#_map_npoints_keyword_RADIUS">RADIUS</a>=<span class="result">RADIUS</span>, <a href="#_map_npoints_keyword_MIDDLE">MIDDLE</a>=<span class="result">MIDDLE</span>, <a href="#_map_npoints_keyword_TWO_BY_TWO">TWO_BY_TWO</a>=<span class="result">TWO_BY_TWO</span>)</p>
117       
118          <div class="comments">
119</div>
120
121          <h3>Return value</h3><div class="preformat">
122 An (np0,np1) array giving the distance in meter between np0
123 points P0 and np1 points P1. Element (i,j) of the output is the
124 distance between element P0[i] and P1[j].
125 If keyword /TWO_BY_TWO is given then <a href="..//Interpolation/map_npoints.html">map_npoints</a> returns
126 an np-elements vector giving the distance in meter between P0[i]
127 and P1[i] (in that case, we have np0 = np1 = np) ; if /MIDDLE see this keyword.</div>
128
129         
130            <h3>Parameters</h3>
131       
132           
133            <h4 id="_map_npoints_param_lon0">lon0&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
134              <span class="attr">in</span>
135             
136             
137              <span class="attr">required</span>
138             
139             
140             
141             
142            </h4>
143       
144          <div class="comments"></div>
145           
146            <h4 id="_map_npoints_param_lat0">lat0&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
147              <span class="attr">in</span>
148             
149             
150              <span class="attr">required</span>
151             
152             
153             
154             
155            </h4>
156       
157          <div class="comments">
158 np0 elements vector. longitudes and latitudes of np0 points P0
159</div>
160           
161            <h4 id="_map_npoints_param_lon1">lon1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
162              <span class="attr">in</span>
163             
164             
165              <span class="attr">required</span>
166             
167             
168             
169             
170            </h4>
171       
172          <div class="comments"></div>
173           
174            <h4 id="_map_npoints_param_lat1">lat1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
175              <span class="attr">in</span>
176             
177             
178              <span class="attr">required</span>
179             
180             
181             
182             
183            </h4>
184       
185          <div class="comments">
186 np1 elements vector. longitude and latitude of np1 points P1
187</div>
188           
189
190         
191
192         
193
194            <h3>Keywords</h3>
195           
196            <h4 id="_map_npoints_keyword_AZIMUTH">AZIMUTH&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
197             
198             
199             
200             
201             
202             
203             
204             
205            </h4>
206       
207            <div class="comments">
208 A named variable that will receive the azimuth of the great
209 circle connecting the two points, P0 to P1
210</div>
211           
212            <h4 id="_map_npoints_keyword_RADIANS">RADIANS&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
213             
214             
215             
216             
217             
218             
219             
220             
221            </h4>
222       
223            <div class="comments">
224 if set, inputs and angular outputs are in radians, otherwise degrees.
225</div>
226           
227            <h4 id="_map_npoints_keyword_RADIUS">RADIUS&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
228             
229             
230             
231             
232             
233             
234              <span class="attr">default:</span> <span class="value">6378206.4d0</span>
235             
236            </h4>
237       
238            <div class="comments">
239 If given, return the distance between the two points calculated using the
240 given radius.
241 Default value is the Earth radius.
242</div>
243           
244            <h4 id="_map_npoints_keyword_MIDDLE">MIDDLE&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
245             
246             
247             
248             
249             
250             
251             
252             
253            </h4>
254       
255            <div class="comments">
256 to get the longitude/latitude of the middle point between P0 and P1.
257</div>
258           
259            <h4 id="_map_npoints_keyword_TWO_BY_TWO">TWO_BY_TWO&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
260             
261             
262             
263             
264             
265             
266             
267             
268            </h4>
269       
270            <div class="comments">
271 If given, then <a href="..//Interpolation/map_npoints.html">map_npoints</a> returns the distances between
272 number n of P0 points and number n of P1 pointsi.
273 In that case, np0 and np1 must be equal.
274</div>
275           
276         
277
278          <h3>Examples</h3><div class="preformat">
279   IDL> print, $
280   IDL> map_npoints([-105.15,1],[40.02,1],[-0.07,100,50],[51.30,20,0])
281 7551369.3 5600334.8
282 12864354. 10921254.
283 14919237. 5455558.8
284
285   IDL> lon0 = [-10, 20, 100]
286   IDL> lat0 = [0, -10, 45]
287   IDL> lon1 = [10, 60, 280]
288   IDL> lat1 = [0, 10, 45]
289   IDL> dist = map_npoints(lon0, lat0, lon1, lat1, AZIMUTH = azi)
290   IDL> help, dist, azi
291 DIST DOUBLE = Array[3, 3]
292 AZI DOUBLE = Array[3, 3]
293   IDL> print, dist[4*lindgen(3)], azi[4*lindgen(3)]
294 2226414.0 4957944.5 10018863.
295 90.000000 64.494450 4.9615627e-15
296   IDL> dist = map_npoints(lon0, lat0, lon1, lat1, AZIMUTH = azi, /TWO_BY_TWO)
297   IDL> help, dist, azi
298 DIST DOUBLE = Array[3]
299 AZI DOUBLE = Array[3]
300   IDL> print, dist, azi
301 2226414.0 4957944.5 10018863.
302 90.000000 64.494450 4.9615627e-15
303   IDL> print, map_2points(lon0[0], lat0[0], lon1[0], lat1[0])
304 20.000000 90.000000
305   IDL> print, map_npoints(lon0[0], lat0[0], lon1[0], lat1[0], AZIMUTH=azi)/6378206.4d0 / !dtor, azi
306 20.000000
307 90.000000
308
309   IDL> lon0 = [-10, 20, 100]
310   IDL> lat0 = [0, -10, 45]
311   IDL> lon1 = [10, 60, 280]
312   IDL> lat1 = [0, 10, 45]
313   IDL> mid = map_npoints(lon0, lat0, lon1, lat1, /MIDDLE, /TWO_BY_TWO)
314   IDL> print, reform(mid[0,*]), reform(mid[1,*])
315 0.0000000 40.000000 190.00000
316 0.0000000 -1.5902773e-15 90.000000
317   IDL> print, (map_2points(lon0[0], lat0[0], lon1[0], lat1[0], npath = 3))[*, 1]
318 0.0000000 0.0000000
319   IDL> print, (map_2points(lon0[1], lat0[1], lon1[1], lat1[1], npath = 3))[*, 1]
320 40.000000 -1.5902773e-15
321   IDL> print, (map_2points(lon0[2], lat0[2], lon1[2], lat1[2], npath = 3))[*, 1]
322 190.00000 90.000000
323</div>
324          <h3>Version history</h3>
325         
326          <h4>Version</h4><div class="preformat">
327 $Id: map_npoints.pro 371 2008-08-07 09:32:02Z pinsard $
328</div>
329          <h4>History</h4><div class="preformat">
330 Based on the IDL function map_2points.pro,v 1.6 2001/01/15
331 Sebastien Masson (smasson@lodyc.jussieu.fr)
332 October 2003
333</div>
334         
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346         
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348         
349       
350          <h3>Statistics</h3>
351          <table class="statistics">
352            <tr><td>McCabe cyclic</td><td>          16</td></tr>
353            <tr><td>McCabe essential</td><td>           1</td></tr>
354            <tr><td>McCabe modular design</td><td>           1</td></tr>
355          </table>
356         
357       
358        </div>
359       
360      </div>
361
362     
363
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