subroutine cgrid(gm,rplnt,pmin,pmax,ntau,zalt,temp
     &   ,pres,dens,col,natm,z,tmp,prs,den,clm)

        implicit double precision (a-h,o-z)
        include "parameters.dat"

        dimension zalt(nd3),temp(nd3),pres(nd3),dens(nd3,0:4)
     &   ,col(nd3,0:4),z(nd1),tmp(nd1),prs(nd1),den(nd1,0:4)
     &   ,clm(nd1,0:4)

        dlmin = dlog10(pmin)
        dlmax = dlog10(pmax)
        dlstep = (dlmax - dlmin) / float(ntau - 1)

        do nt = 1, ntau 

           dum1 = dlmin + (float(nt - 1) * dlstep)

           prs(nt) = 10.d0 ** dum1
           if (prs(nt) .le. pres(1)) then
              tmp(nt) = temp(1)
              do im = 0, 4
                 den(nt,im) = dens(1,im)*prs(nt)/pres(1)
                 clm(nt,im) = col(1,im)*prs(nt)/pres(1)
              end do
           else
              tmp(nt) = fintrp(pres,temp,natm,prs(nt))
              do im = 0, 4
                 den(nt,im) = fintrp(pres,dens(1,im),natm,prs(nt))
                 clm(nt,im) = fintrp(pres,col(1,im),natm,prs(nt))
              end do
              i1 = locate(pres,natm,prs(nt))
              i2 = i1 + 1
              pl1 = dlog(pres(i1))
              pl2 = dlog(pres(i2))
              pl = dlog(prs(nt))
              z(nt) = zalt(i1)+(pl-pl1)*(zalt(i2)-zalt(i1))
     &          /(pl2-pl1) 
           end if

        end do

        return
        end