1 | |
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2 | function dist=spheric_dist(lat1,lat2,lon1,lon2) |
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3 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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4 | % |
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5 | % function dist=spheric_dist(lat1,lat2,lon1,lon2) |
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6 | % |
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7 | % compute distances for a simple spheric earth |
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8 | % |
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9 | % input: |
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10 | % |
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11 | % lat1 : latitude of first point (matrix) |
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12 | % lon1 : longitude of first point (matrix) |
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13 | % lat2 : latitude of second point (matrix) |
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14 | % lon2 : longitude of second point (matrix) |
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15 | % |
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16 | % output: |
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17 | % dist : distance from first point to second point (matrix) |
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18 | % |
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19 | % Further Information: |
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20 | % http://www.brest.ird.fr/Roms_tools/ |
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21 | % |
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22 | % This file is part of ROMSTOOLS |
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23 | % |
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24 | % ROMSTOOLS is free software; you can redistribute it and/or modify |
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25 | % it under the terms of the GNU General Public License as published |
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26 | % by the Free Software Foundation; either version 2 of the License, |
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27 | % or (at your option) any later version. |
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28 | % |
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29 | % ROMSTOOLS is distributed in the hope that it will be useful, but |
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30 | % WITHOUT ANY WARRANTY; without even the implied warranty of |
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31 | % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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32 | % GNU General Public License for more details. |
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33 | % |
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34 | % You should have received a copy of the GNU General Public License |
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35 | % along with this program; if not, write to the Free Software |
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36 | % Foundation, Inc., 59 Temple Place, Suite 330, Boston, |
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37 | % MA 02111-1307 USA |
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38 | % |
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39 | % Copyright (c) 2001-2006 by Pierrick Penven |
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40 | % e-mail:Pierrick.Penven@ird.fr |
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41 | % |
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42 | %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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43 | % |
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44 | % Earth radius |
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45 | % |
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46 | R=6367442.76; |
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47 | % |
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48 | % Determine proper longitudinal shift. |
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49 | % |
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50 | l=abs(lon2-lon1); |
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51 | l(l>=180)=360-l(l>=180); |
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52 | % |
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53 | % Convert Decimal degrees to radians. |
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54 | % |
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55 | deg2rad=pi/180; |
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56 | lat1=lat1*deg2rad; |
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57 | lat2=lat2*deg2rad; |
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58 | l=l*deg2rad; |
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59 | % |
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60 | % Compute the distances |
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61 | % |
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62 | dist=R*asin(sqrt(((sin(l).*cos(lat2)).^2)+(((sin(lat2).*cos(lat1))-... |
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63 | (sin(lat1).*cos(lat2).*cos(l))).^2))); |
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64 | return |
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