[ferret_users] looping through the files

[Steeven Paul Yerraguntla <steevenpaul@xxxxxxxxx>]

Dear ferreters,
          I wanted to plot few tracks over a filled plot.  Lat, Longiutes of each track are in a single file. I need to apply a loop through many text files using repeat statement, to over plot tracks. To do so, i used a procedure given in archieves.  I am encountering an error when running the following script.  When i use "cancel region" before starting looping Error message says:  


!-> REPEAT: NF:1
 !-> define symbol ff = 1
 !-> SET DATA/EZ/format=delimited/delimiter="\t"/var="lat,lon"  "./1990_nov_01.txt"[d=2]
 **ERROR: variable unknown or not in data set: FILENAMES[I=1]


cancel data./`filenames[i=1]`"[d=2]
Command file, command group, or REPEAT execution aborted

When i did not use "cancel region" statement before repeat statement error as follows

!-> REPEAT: NF:1

 !-> define symbol ff = 1
 !-> SET DATA/EZ/format=delimited/delimiter="\t"/var="lat,lon"  "./1990_nov_01.txt"[d=2]
 **ERROR: illegal limits: X axis of LON
plot/VS/line/thickness=2/color=black/over lon[d=3],lat[d=3]

Command file, command group, or REPEAT execution aborted

Please let me know to overcome this problem.  sample text file for track plotting is attached to this mail. Journal i used as follows
-------------------------------------------------------------------------------------------------------------

use sst.nc
SET REGION/X=75:100/y=5:25
fill/l=1   SST
! looping through files  
define axis/x=1:22:1 xfile

define grid/x=xfile  gfile
file/grid=gfile/format=delimited/var="filenames" filenames.txt
! cancel region
        repeat/range=1:22:1/name=nf   (    ;\
                        define symbol ff = `nf` ;\
                        can var/all   ;\
                        file/format=delimited/delimiter="\t"/var="lat,lon"  "./`filenames[i=($ff)]`"[d=2] ;\
                        plot/VS/line/thickness=2/color=black/over lon[d=3],lat[d=3]  ;\
                        cancel data "./`filenames[i=($ff)]`"[d=2];\
                                      )

--------------------------------------------------------------------------------------------------------------

thanks n regards,
--

Steeven Paul Y                              
Research Fellow
National Institute of Oceanography(NIO)
Regional Center, Visakhapatnam (RCV)                 
176 Lawsons Bay Colony
Visakhapatnam - 530017

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