/*N ruggedness.aml
/*P----------------------------- Purpose -------------------------------------
/*
/*  This AML calculates the mean difference in elevation between 


/*A---------------------------- Arguments ------------------------------------
/*G------------------------ Global Variables ---------------------------------
/*L------------------------ Local Variables ----------------------------------
/*I---------------- Input/Output Files, Coverages, etc. ----------------------
/*D----------------- Detailed Remarks, Assumptions, etc. ---------------------
/*R----------- Other AMLs, Menus, or Programs Run from this AML --------------
/*B----------- Other AMLs, Menus, or Programs which Run this AML -------------
/*O-------------------- Operating System Dependencies ------------------------
/*H----------------------------- History -------------------------------------
/*
/* Jacek Blaszczynski 06/1999 Original Coding
/* 
/*E===========================================================================
&severity &error &routine bailout 
&args in_elev 

/* Check arguments
&call chkargs

/* Do the work
&call main

&return /* End of ruggedness.aml

/*--------------
&routine chkargs
/*--------------
&if [SHOW PROGRAM] <> GRID &then &do
  &type This aml must be run from GRID.
  &call bailout
&end
&do arg &list in_elev 
  &if [NULL [VALUE %arg%]] &then &do
    &call usage
    &call bailout
  &end
&end
&if not [EXISTS %in_elev% -GRID] &then &do
  &type Input grid: %in_elev%, does not exist.
  &call bailout
&end


&return /* End of routine chkargs


/*-----------
&routine main
/*-----------

&terminal 9999
display 9999 position ur
setwindow %in_elev% %in_elev%
setcell %in_elev%
mape %in_elev%
gridpaint %in_elev% value linear nowrap gray
&if [EXISTS ssdiff -GRID] &then &do
  kill ssdiff all
&end
&if [EXISTS tri -GRID] &then &do
  kill tri all
&end

DOCELL
  ssdiff = ( ( sqr ( %in_elev%(0,0) - %in_elev%(-1,-1) ) ) ~
  + ( sqr ( %in_elev%(0,0) - %in_elev%(0,-1) ) ) ~
  + ( sqr ( %in_elev%(0,0) - %in_elev%(1,-1) ) ) ~
  + ( sqr ( %in_elev%(0,0) - %in_elev%(1,0) ) ) ~
  + ( sqr ( %in_elev%(0,0) - %in_elev%(1,1) ) ) ~
  + ( sqr ( %in_elev%(0,0) - %in_elev%(0,1) ) ) ~
  + ( sqr ( %in_elev%(0,0) - %in_elev%(-1,1) ) ) ~
  + ( sqr ( %in_elev%(0,0) - %in_elev%(-1,0) ) ) )
END
gridpaint SSDIFF value linear nowrap gray
TRI = sqrt (ssdiff)
gridpaint tri value linear nowrap gray
&return

/*------------
&routine usage
/*------------
&type Usage: &r ruggedness <in_elev_grid> 
&return /* End of routine usage

/*-----------
&routine exit
/*-----------
&return /* End of routine exit

/*--------------
&routine bailout
/*--------------
&severity &error &ignore
&call exit
&return &error Bailing out of shedstats.aml...