SUBROUTINE GETGRDELEV(M,IERREL)
    
       USE BLK1MOD
       USE BLKMAP
       REAL*8 XXX,YYY

       XXX=XUSR(M)
       YYY=YUSR(M)
       
!                                 test for XXX and YYY outside grid limits
       
       IF(XXX .LT. XXORG-CELLSIZX/2.  .OR. XXX .GT. XXORG+(FLOAT(NCOLS1)+0.5)*CELLSIZX) THEN
         WD(M)=-9998.
         RETURN
       ELSE
         IF(YYY .LT. YYORG-CELLSIZY/2.  .OR. YYY .GT. YYORG+(FLOAT(NROWS1)+0.5)*CELLSIZY) THEN
           WD(M)=-9998.
           RETURN
         ENDIF
       ENDIF  
!                                Set row length in bytes and set temp origin       
       LENROW=NCOLS1*4
       XORGT=XXORG
       YORGT=YYORG
!                                 Get row and column from lower left  
       
       NCOL=INT((XXX-XORGT)/CELLSIZX)+1                
       NROWU=INT((YYY-YORGT)/CELLSIZY)+1               
       
!                                 Establish fraction within cell
       
       XFRAC=(XXX-XORGT-(NCOL-1)*CELLSIZX)/CELLSIZX    
       YFRAC=((YYY-YORGT-(NROWU-1)*CELLSIZY))/CELLSIZY 
      
!                                  Let fraction overlap outer edge
       
       IF(XFRAC .LT. 0.) XFRAC=0.
       IF(YFRAC .LT. 0.) YFRAC=0.
       
!                                  Set up file position across columns, up rows and combine
       NCOLFIL=(NCOL-1)*4
       NROWFIL=(NROWS1-NROWU+1)*LENROW                 
       NFILPOS=NCOLFIL+NROWFIL                         
       
!                                   Read lower left the lower right allow fo upper limit       
       
       READ(203,POS=NFILPOS+1) ELEVLL
       IF(NCOL .LT. NCOLS1) NFILPOS=NFILPOS+4
       READ(203,POS=NFILPOS+1) ELEVLR

!                                    Test for point ouside grid        
       
       IF(ELEVLL .LT. -9000.  .OR.  ELEVLR .LT. -9000.) THEN
         WD(M)=-9998.
         RETURN
       ENDIF  
       
!                                    Now mode to next row up and column
       
       NROWFIL=(NROWS1-NROWU)*LENROW                    
       NFILPOS=NCOLFIL+NROWFIL                          
       READ(203,POS=NFILPOS+1) ELEVUL
       IF(NCOL .LT. NCOLS1) NFILPOS=NFILPOS+4
       READ(203,POS=NFILPOS+1) ELEVUR

!                                     Test again
       
       IF(ELEVUL .LT. -9000.  .OR.  ELEVUR .LT. -9000.) THEN
         WD(M)=-9998.
         RETURN
       ENDIF  
!                                     interpolate along along lower and upper level
       
       ELEVL=XFRAC*(ELEVLR-ELEVLL)+ELEVLL
       ELEVU=XFRAC*(ELEVUR-ELEVUL)+ELEVUL
       
!                                   Get final value, store and display       
       
       AMAPVAL=YFRAC*(ELEVU-ELEVL)+ELEVL 
       wd(m)=amapval
       FPN = WD(M)*10. 
       X = CORD(M,1) 
       Y = CORD(M,2) - .11 
       IF(X .GT. 0.  .AND.  X .LT. HSIZE  .AND.  Y .GT. 0.  .AND.  Y .LT. 7.5) THEN
         CALL RRED 
         CALL NUMBR(X,Y,0.1,FPN,0.0,-1) 
		endif

       RETURN

       
       END