exch2_global_Nx = nbPts
exch2_global_Ny = nbPts/W2_mapIO
nbPts = 0
ii = nbPts + exch2_tBasex(tId) + exch2_tBasey(tId)*fNx
nbPts = nbPts + fNx*fNy
INTEGER tNx, tNy, fNx, fNy, nbPts, fBaseX, fBaseY