Parent Topic: <A href="http://www.pcigeomatics.com/cgi-bin/pcihlp/MODEL">MODEL</a><hr>
<H3>Attribute Data</H3>
Attribute data is a set of numeric and/or character values which are
associated with a range of values. For example:
<P>
<PRE>
        23 : 27   ;  1.3  19  river  Mississippi
</PRE>
means that values on the range 23 to 27 are associated with the two
numeric attributes 1.3 and 19 and the two character attributes
'river' and 'Mississippi'. The 'Using PCI Software' manual has a a
chapter giving more detailed information on attribute data.<p>
The MODEL program can access attribute data held in a text segment
on PCIDSK files or in text files on disk. This is accomplished by
tying the attribute data to a specific image channel (layer) and
then using the grey level values for individual pixels to match
against the ranges in the attribute data.<p>
A special feature of MODEL is the ability to use lookup table (LUT)
and pseudo-colour table (PCT) segments held on a PCIDSK file as
attribute data. LUT data is equivalent to attribute data having 256
entries, each entry having one numeric attribute. PCT data is
equivalent to attribute data having 256 entries, each entry having
three numeric attributes (i.e., red, green, blue).
<P>
<hr>
Parent Topic: <A href="http://www.pcigeomatics.com/cgi-bin/pcihlp/MODEL">MODEL</a><br>
<a href="http://www.pcigeomatics.com/dev_corner/pcihlp_gateway.html">About PCI Help Gateway</a>