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On Fri, 2011-07-29 at 18:13 +0530, H.S.Rai wrote:
<BLOCKQUOTE TYPE=CITE>
<PRE>
I wish to convert point data (say with attribute 'A' having value
between 0 - 100), in to thematic map, showing area divided into four
region as:
Region I : Value of A between 0-25
Region II : Value of A between 25-50
Region III: Value of A between 50-75
Region IV: Value of A between 75-100
What command or sequence of command I need to use. Any pointer to
document / tutorial will be appreciated.
</PRE>
</BLOCKQUOTE>
<BR>
I think that v.reclass does what you want.<BR>
Two ways to do this (see the man page)<BR>
<BR>
1) You'll need to first create a reclass file that looks like:<BR>
<BR>
cat 1<BR>
where A <= 25<BR>
cat 2<BR>
where A>25 and A<=50<BR>
....<BR>
<BR>
then run<BR>
v.reclass in=point_vect out=point_reclass rule=reclass_file<BR>
<BR>
Note that in the new vector you'll loose any attributes from the original point data.<BR>
<BR>
2) Alternatively you could add an additional column in the original vector and populate it with values based on A, as so:<BR>
v.db.addcol points column="label varchar(12)"<BR>
v.db.update points col=label val='Region I' where='A<=25'<BR>
v.db.update points col=label val='Region II' where='A>25 and A<=50'<BR>
...<BR>
<BR>
and now do the v.reclass step but use the parameter 'column=label' to create a new reclassed vector based on those labels<BR>
<BR>
-- <BR>
Micha<BR>
<BR>
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