r.rescale.inf r.rescale.inf NAME r.rescale.inf - 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) SYNOPSIS r.rescale.inf r.rescale.inf help r.rescale.inf tab=name key=name col=name cats=name input=name output=name [join=tab,tabkey,pkey] DESCRIPTION r.rescale.inf 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.rescale.inf 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 represent a range of 100 values from the database column used in the rescale operation. The database column being evaluated must be numeric in type. To identify the data types of columns in a database table use the g.column.inf command with the [-v] flag. r.rescale.inf does not take outlying data values into account. Therefore, if the range of values for a database column contains a limited number of extreme values the resulting rescale operation will be skewed in the direction of these values. COMMAND LINE OPTIONS Parameters tab=database_table_name Table containing a column linked to category values in an existing raster map. key=database_column_name Column corresponding to category values in an existing raster map. col=database_column_name Column to base rescale operation on which is numeric in type. GRASS 5.0beta6 GRASS Development Team 1 r.rescale.inf r.rescale.inf cats=value Number of categories to define in the resulting reclass map. input=map Name of an existing raster file with category values linked to a column in the currently selected databae. output=map Name of new raster map. join=tab,tabkey,pkey Tab is the table used to develop the current SQL 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 stf1_main is a table containing column values associated with category values in a the GRASS raster file blkgrp.ids. In addition, assume that stf1_main is a table containing attribute data on age in the column pop100. In this example stf1_main is the table associated with the GRASS raster map and tract_blck is the column linking stf1_main to the GRASS category file. The column pop100 in stf1_main will be the basis for the rescale effort. To specify the rescale: r.rescale.inf tab=stf1_main key=tract_blck col=pop100 cats=5 input=blkgrp.ids output=pop100.rescale Specifying these conditions would insure that all rows from table stf1_main which satisfy the query criteria would be related to the spatial features in the GRASS data layer via the GRASS category values. BUGS None known. NOTE This program requires the Informix database software. 2 GRASS Development Team GRASS 5.0beta6 r.rescale.inf r.rescale.inf SEE ALSO g.column.inf, g.select.inf, g.stats.inf, g.table.inf, d.rast.inf, d.site.inf, d.vect.inf, d.what.r.inf, d.what.s.inf, d.what.v.inf, r.reclass.inf, v.reclass.inf AUTHOR James A. Farley, Wang Song and W. Fredrick Limp University of Arkansas, CAST NOTICE This program is part of the contrib section of the GRASS distribution. As such, it is externally contributed code that has not been examined or tested by the Office of GRASS Integration. GRASS 5.0beta6 GRASS Development Team 3