Parent Topic: <A href="http://www.pcigeomatics.com/cgi-bin/pcihlp/MODEL|Examples">Examples</a><hr>
<H4>Detailed</H4>
A project requires the generation of a map showing areas of high
fire risk. The study region is mountainous and it has been
determined that the risk of fire increases with elevation and ground
cover type. The base elevation at which the risk starts varies with
the time of the year and the amount of rainfall which has occurred.
This base elevation is computed on a monthly basis from available
weather data.<p>
The file `irvine.pix' contains 16-bit elevation data held in channel
10 (signed 16-bit channel) expressed in metres. Channel 6 contains
Land use / Land coverage data obtained from the U.S. Geological
Survey. Segment 28 on the database contains the attribute data
identifying the coverage codes. A partial listing of this data is
shown below:
<P>
<PRE>
  ! Land Use / Land Cover Classification System from USGS.
  !
  ! Grey level ; Level 1      Level 2
  !
           11 ; Urban        Residential
           12 ; Urban        Commercial
           13 ; Urban        Industrial
           14 ; Urban        Transportation
           15 ; Urban        Commercial/Industrial 
           16 ; Urban        Mixed
           17 ; Urban        Other
           21 ; Agriculture  Crop/Pasture
           22 ; Agriculture  Orchards
           23 ; Agriculture  Feeding
           24 ; Agriculture  Other
           31 ; Rangeland    Herbaceous
                         . . .
</PRE>
It has been determined that only land classed as 'Agriculture',
'Rangeland' and 'Forest' are at risk. The model will generate a new
output channel (layer) showing areas of risk and will also generate
a report giving the acreage of each class at risk. To improve the
appearance of the report, the following text was entered into a text
file, 'labels.att':
<P>
<PRE>
  ! Channel 7 Class ;  Class Name
          0         ;  'No Risk'
         20         ;  Agriculture
         30         ;  Rangeland
         40         ;  Forest
</PRE>
The actual model is shown below and was entered into a text file
called 'risk.mod'.
<P>
<PRE>
                Fire Risk Zone Model

  !In this model, we are assuming that channel 6 is the coverage
  !and channel 10 is elevation data.
 
  !Setup Section
 
  input 'Enter base elevation: ' #base;  !Prompt user for elevation
  seta  %6 = 28;                         !Land use/Land cover attributes
  seta  %7 = 'labels.att';               !Labels for report
 
  print 'Channel 7 will receive the new coverage map.';
 
  !Equations section
 
  #elev = %10;                  !elevation to a single value
  if (#elev&lt;#base) then
      %7 = 0;
  else
      $class = %6.1;                    !Land class
      if     ($class = 'Agriculture') then
         %7 = 20;
      extrif ($class = 'Rangeland') then
         %7 = 30;
      extrif ($class = 'Forest') then
         %7 = 40;
      else
         %7 = 0;
      endif;
  endif;
 
 !Report Section:  Generate an area report with title
 
 title 'Fire Risk Area Report';

 report %7 by hectares identify %7.1;
</PRE>
To actually run the model, the following commands are entered:
<P>
<PRE>
 EASI&gt; FILE = &quot;irvine.pix&quot;
 EASI&gt; SOURCE=&quot;risk.mod&quot;
 EASI&gt; UNDEFVAL=
 EASI&gt; REPORT = &quot;term&quot;
 EASI&gt; RUN MODEL
</PRE>
A copy of the generated report is shown below:
<P>
<PRE>
  Fire Risk Area Report

  Value    Pixels         Hectares    Identifier

      0     91059         8195.310    No Risk
     20     46025         4142.250    Agriculture
     30    119843        10785.870    Rangeland
     40      5217          469.530    Forest
</PRE>
<hr>
Parent Topic: <A href="http://www.pcigeomatics.com/cgi-bin/pcihlp/MODEL|Examples">Examples</a><br>
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