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											2018-02-08 21:28:33 -05:00
										 |  |  | subroutine azdist(grid1,grid2,utch,nAz,nEl,nDmiles,nDkm,nHotAz,nHotABetter) | 
					
						
							|  |  |  | 
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							|  |  |  |   character*(*) grid1,grid2 | 
					
						
							|  |  |  |   character*6 MyGrid,HisGrid,mygrid0,hisgrid0 | 
					
						
							|  |  |  |   real*8 utch,utch0 | 
					
						
							|  |  |  |   logical HotABetter,IamEast | 
					
						
							|  |  |  |   real eltab(22),daztab(22) | 
					
						
							|  |  |  |   data eltab/18.,15.,13.,11.,9.,8.,7.,6.,5.3,4.7,4.,3.3,2.7,    & | 
					
						
							|  |  |  |        2.,1.5,1.,0.8,0.6,0.4,0.2,0.0,0.0/ | 
					
						
							|  |  |  |   data daztab/21.,18.,16.,15.,14.,13.,12.,11.,10.7,10.3,10.,    & | 
					
						
							|  |  |  |        10.,10.,10.,10.,10.,10.,9.,9.,9.,8.,8./ | 
					
						
							|  |  |  |   data mygrid0/"      "/,hisgrid0/"      "/,utch0/-999.d0/ | 
					
						
							|  |  |  |   save | 
					
						
							|  |  |  | 
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											2018-08-05 11:33:30 -04:00
										 |  |  |   MyGrid=grid1//'  ' | 
					
						
							|  |  |  |   HisGrid=grid2//'  ' | 
					
						
							|  |  |  |   if(ichar(MyGrid(5:5)).eq.0)  MyGrid(5:6)='  ' | 
					
						
							|  |  |  |   if(ichar(HisGrid(5:5)).eq.0) HisGrid(5:6)='  ' | 
					
						
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											2018-02-08 21:28:33 -05:00
										 |  |  | 
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							|  |  |  |   if(MyGrid.eq.HisGrid) then | 
					
						
							|  |  |  |      naz=0 | 
					
						
							|  |  |  |      nel=0 | 
					
						
							|  |  |  |      ndmiles=0 | 
					
						
							|  |  |  |      ndkm=0 | 
					
						
							|  |  |  |      nhotaz=0 | 
					
						
							|  |  |  |      nhotabetter=1 | 
					
						
							|  |  |  |      go to 999 | 
					
						
							|  |  |  |   endif | 
					
						
							|  |  |  | 
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							|  |  |  |   if(mygrid.eq.mygrid0 .and. hisgrid.eq.hisgrid0 .and.              & | 
					
						
							|  |  |  |        abs(utch-utch0).lt.0.1666667d0) go to 900 | 
					
						
							|  |  |  |   utch0=utch | 
					
						
							|  |  |  |   mygrid0=mygrid | 
					
						
							|  |  |  |   hisgrid0=hisgrid | 
					
						
							|  |  |  |   utchours=utch | 
					
						
							|  |  |  | 
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							|  |  |  |   if(MyGrid(5:5).eq.' ') MyGrid(5:5)='m' | 
					
						
							|  |  |  |   if(MyGrid(6:6).eq.' ') MyGrid(6:6)='m' | 
					
						
							|  |  |  |   if(HisGrid(5:5).eq.' ') HisGrid(5:5)='m' | 
					
						
							|  |  |  |   if(HisGrid(6:6).eq.' ') HisGrid(6:6)='m' | 
					
						
							|  |  |  | 
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							|  |  |  |   if(MyGrid.eq.HisGrid) then | 
					
						
							|  |  |  |      Az=0. | 
					
						
							|  |  |  |      Dmiles=0. | 
					
						
							|  |  |  |      Dkm=0.0 | 
					
						
							|  |  |  |      El=0. | 
					
						
							|  |  |  |      HotA=0. | 
					
						
							|  |  |  |      HotB=0. | 
					
						
							|  |  |  |      HotABetter=.true. | 
					
						
							|  |  |  |      go to 900 | 
					
						
							|  |  |  |   endif | 
					
						
							|  |  |  |   call grid2deg(MyGrid,dlong1,dlat1) | 
					
						
							|  |  |  |   call grid2deg(HisGrid,dlong2,dlat2) | 
					
						
							|  |  |  |   eps=1.e-6 | 
					
						
							|  |  |  |   Az=0. | 
					
						
							|  |  |  |   Dmiles=0. | 
					
						
							|  |  |  |   Dkm=0.0 | 
					
						
							|  |  |  |   El=0. | 
					
						
							|  |  |  |   HotA=0. | 
					
						
							|  |  |  |   HotB=0. | 
					
						
							|  |  |  |   HotABetter=.true. | 
					
						
							|  |  |  |   if(abs(dlat1-dlat2).lt.eps .and. abs(dlong1-dlong2).lt.eps) go to 900 | 
					
						
							|  |  |  | 
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							|  |  |  |   difflong=mod(dlong1-dlong2+720.0,360.0) | 
					
						
							|  |  |  |   if(abs(dlat1+dlat2).lt.eps .and. abs(difflong-180.0).lt.eps) then | 
					
						
							|  |  |  | ! Antipodes | 
					
						
							|  |  |  |      Dkm=20400 | 
					
						
							|  |  |  |      go to 900 | 
					
						
							|  |  |  |   endif | 
					
						
							|  |  |  | 
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							|  |  |  |   call geodist(dlat1,dlong1,dlat2,dlong2,Az,Baz,Dkm) | 
					
						
							|  |  |  | 
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							|  |  |  |   ndkm=Dkm/100 | 
					
						
							|  |  |  |   j=ndkm-4 | 
					
						
							|  |  |  |   if(j.lt.1) j=1 | 
					
						
							|  |  |  |   if(j.gt.21)j=21 | 
					
						
							|  |  |  |   if(Dkm.lt.500.0) then | 
					
						
							|  |  |  |      El=18.0 | 
					
						
							|  |  |  |   else | 
					
						
							|  |  |  |      u=(Dkm-100.0*ndkm)/100.0 | 
					
						
							|  |  |  |      El=(1.0-u)*eltab(j) + u*eltab(j+1) | 
					
						
							|  |  |  |   endif | 
					
						
							|  |  |  | 
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							|  |  |  |   daz=daztab(j) + u * (daztab(j+1)-daztab(j)) | 
					
						
							|  |  |  |   Dmiles=Dkm/1.609344 | 
					
						
							|  |  |  | 
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							|  |  |  |   tmid=mod(UTChours-0.5*(dlong1+dlong2)/15.0+48.0,24.0) | 
					
						
							|  |  |  |   IamEast=.false. | 
					
						
							|  |  |  |   if(dlong1.lt.dlong2) IamEast=.true. | 
					
						
							|  |  |  |   if(dlong1.eq.dlong2 .and. dlat1.gt.dlat2) IamEast=.false. | 
					
						
							|  |  |  |   azEast=baz | 
					
						
							|  |  |  |   if(IamEast) azEast=az | 
					
						
							|  |  |  |   if((azEast.ge.45.0 .and. azEast.lt.135.0) .or.                    & | 
					
						
							|  |  |  |        (azEast.ge.225.0 .and. azEast.lt.315.0)) then | 
					
						
							|  |  |  | ! The path will be taken as "east-west". | 
					
						
							|  |  |  |      HotABetter=.true. | 
					
						
							|  |  |  |      if(abs(tmid-6.0).lt.6.0) HotABetter=.false. | 
					
						
							|  |  |  |      if((dlat1+dlat2)/2.0 .lt. 0.0) HotABetter=.not.HotABetter | 
					
						
							|  |  |  |   else | 
					
						
							|  |  |  | ! The path will be taken as "north-south". | 
					
						
							|  |  |  |      HotABetter=.false. | 
					
						
							|  |  |  |      if(abs(tmid-12.0).lt.6.0) HotABetter=.true. | 
					
						
							|  |  |  |   endif | 
					
						
							|  |  |  |   if(IamEast) then | 
					
						
							|  |  |  |      HotA = Az - daz | 
					
						
							|  |  |  |      HotB = Az + daz | 
					
						
							|  |  |  |   else | 
					
						
							|  |  |  |      HotA = Az + daz | 
					
						
							|  |  |  |      HotB = Az - daz | 
					
						
							|  |  |  |   endif | 
					
						
							|  |  |  |   if(HotA.lt.0.0)   HotA=HotA+360.0 | 
					
						
							|  |  |  |   if(HotA.gt.360.0) HotA=HotA-360.0 | 
					
						
							|  |  |  |   if(HotB.lt.0.0)   HotB=HotB+360.0 | 
					
						
							|  |  |  |   if(HotB.gt.360.0) HotB=HotB-360.0 | 
					
						
							|  |  |  | 
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							|  |  |  | 900 continue | 
					
						
							|  |  |  |   naz=nint(Az) | 
					
						
							|  |  |  |   nel=nint(el) | 
					
						
							|  |  |  |   nDmiles=nint(Dmiles) | 
					
						
							|  |  |  |   nDkm=nint(Dkm) | 
					
						
							|  |  |  |   nHotAz=nint(HotB) | 
					
						
							|  |  |  |   nHotABetter=0 | 
					
						
							|  |  |  |   if(HotABetter) then | 
					
						
							|  |  |  |      nHotAz=nint(HotA) | 
					
						
							|  |  |  |      nHotABetter=1 | 
					
						
							|  |  |  |   endif | 
					
						
							|  |  |  | 
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							|  |  |  | 999 return | 
					
						
							|  |  |  | end subroutine azdist |