r.rescale.pg(1)        Grass User's Manual	  r.rescale.pg(1)



NNAAMMEE
       rr..rreessccaallee..ppgg  -	Generate  a raster map layer in which the
       categories represent values in  a  database  column  which
       have  been divided into equal interval units. (GRASS-RDBMS
       Raster Interface Program)

SSYYNNOOPPSSIISS
       rr..rreessccaallee..ppgg

       rr..rreessccaallee..ppgg hheellpp

       rr..rreessccaallee..ppgg   ttaabb_=_n_a_m_e	 kkeeyy_=_n_a_m_e   ccooll_=_n_a_m_e	ccaattss_=_n_a_m_e
       iinnppuutt_=_n_a_m_e oouuttppuutt_=_n_a_m_e [jjooiinn_=_t_a_b_,_t_a_b_k_e_y_,_p_k_e_y]

DDEESSCCRRIIPPTTIIOONN
       _r_._r_e_s_c_a_l_e_._p_g  creates  a  reclassed  raster  map  layer by
       dividing the values in a numeric column in  the	currently
       selected database into equal interval units. The number of
       resulting categories is determined by  the  user  via  the
       command	line  parameter  [cats=].  _r_._r_e_s_c_a_l_e_._p_g evaluates
       the range of values for the database  column  and  subsets
       these   values  into  equal  interval  groups  of  records
       returned by the query. For example, if the database column
       contains  values  which	range  from 1-1000 and the [cats]
       value is equal to 10 the resulting raster map  layer  will
       contain the 10 categories:1=1-100, 2=101-200 etc. In other
       words, each category in the new raster map layer will rep-
       resent a range of 100 values from the database column used
       in the rescale operation. The database column being evalu-
       ated  must  be numeric in type. To identify the data types
       of columns in a database table use the _g_._c_o_l_u_m_n_._p_g command
       with  the  _[_-_v_]	flag. _r_._r_e_s_c_a_l_e_._p_g does not take outlying
       data values into account. Therefore, if the range of  val-
       ues  for  a  database  column contains a limited number of
       extreme values the resulting  rescale  operation  will  be
       skewed in the direction of these values.

CCOOMMMMAANNDD LLIINNEE OOPPTTIIOONNSS
   PPaarraammeetteerrss::
       ttaabb==ddaattaabbaasseettaabblleennaammee
	      Table containing a column linked to category values
	      in an existing raster map.



       kkeeyy==ddaattaabbaasseeccoolluummnnnnaammee
	      Column  corresponding  to  category  values  in  an
	      existing raster map.



       ccooll==ddaattaabbaasseeccoolluummnnnnaammee
	      Column  to  base	rescale  operation  on	which  is
	      numeric in type.



       ccaattss==vvaalluuee
	      Number of categories to  define  in  the	resulting
	      reclass map.



       iinnppuutt==mmaapp
	      Name  of an existing raster file with category val-
	      ues linked to a column in  the  currently  selected
	      databae.



       oouuttppuutt==mmaapp
	      Name of new raster map



       jjooiinn==ttaabb,,ttaabbkkeeyy,,ppkkeeyy
	      Tab  is  the  table  used  to  develop  the current
	      postQUEL query.  Tabkey is the database column used
	      to  relate  information  in this table with data in
	      the table linked to the GRASS category  file.  Pkey
	      is the associated column in the table linked to the
	      GRASS category file which is related to  tabkey  in
	      the current table.



       For  instance,  assume that stf1main is a table containing
       column values associated with category  values  in  a  the
       GRASS  raster  file  blkgrp.ids.  In addition, assume that
       stf1main is a table containing attribute data  on  age  in
       the  column  pop100. In this example stf1main is the table
       associated with the GRASS raster map and tractblck is  the
       column  linking	stf1main  to the GRASS category file. The
       column pop100 in  stf1main  will  be  the  basis  for  the
       rescale effort. To specify the rescale:


       _r_._r_e_s_c_a_l_e_._p_g  _t_a_b_=_s_t_f_1_m_a_i_n _k_e_y_=_t_r_a_c_t_b_l_c_k _c_o_l_=_p_o_p_1_0_0 _c_a_t_s_=_5
       _i_n_p_u_t_=_b_l_k_g_r_p_._i_d_s _o_u_t_p_u_t_=_p_o_p_1_0_0_._r_e_s_c_a_l_e


       Specifying these conditions would  insure  that	all  rows
       from table stf1main which satisfy the query criteria would
       be related to the spatial features in the GRASS data layer
       via the GRASS category values.

BBUUGGSS
       None known.

NNOOTTEE
       This program requires the Postgres database software.

SSEEEE AALLSSOO
       _v_._r_e_c_l_a_s_s_._p_g

AAUUTTHHOORR
       Original  Informix  SQL-tools: James A. Farley, Wang Song,
       and W. Fredrick Limp University of Arkansas, CAST


       Postgres  modifications:  Janne	 Soimasuo,   Faculty   of
       Forestry, University of Joensuu, Finland.


       Updated to GRASS 5 by Alex Shevlakov (sixote@yahoo.com)



GRASS 5.0					  r.rescale.pg(1)
