NAME

       ossim-equation - ossim-equation

SYNOPSIS

       ossim-equation "<equation spec>" <input_file1> <input_file2> <input_file...> <output_file>

DESCRIPTION

       Description:  ossim-equation  Takes  a list of images and performs the specified equation.
       The inputsmust be in the same projection as the operations are done at the pixellevel with
       no  renderer  in  th chain. The output file will contain the samegeospatial header info as
       the first image in the input list.

OPTIONS

       --writer-prop <string>
              Adds a property to send to the writer. format is name=value

       -h or --help
              Display this information

       -k <filename>
              keyword list to load from

       -t <filename>
              output a keyword list template

       -w <type>
              Writer   type    (tiff_strip,    jpeg,    etc...    see    ossim-info    --writers)
              (default=tiff_strip)

       Equation Specification:

       sin(x)                 takes the sine of the input sind(x)                takes the sin of
       the input and assumes degree input cos(x)                 takes cosine  of  input  cosd(x)
       takes the cosine of input and assumes input in degrees sqrt(x)                takes square
       root  of  input  log(x)                  takes  the  natural   log   of   input   log10(x)
       takes the log base 10 of the input exp(x)                 takes the e raised to the passed
       in argument abs(x)                 takes the absolute value of the passed in value min(x1,
       x2,  ...  xn)     takes the min of all values in the list max(x1, x2, ... xn)    takes the
       max of all values in the list.

       clamp(image_data, min, max)

       will clamp all data to be between the min max values.
              will set anything less than min to min and anythin larger than max to max

       band(image_data, num)  returns a single band image object

       by selecting band num from input image i1.
              Note

       the first argument must be an image
              and the second argument must be a number

       shift(index, num_x, num_y)

       currently, the first argument must be an image
              variable(i1, i2, ... in) and x, and y must b numbers indicating the delta  in  that
              direction to shift the input.

       blurr(index, rows, cols)

       Will blurr the input image i with a
              rows-by-cols  kernel.  All values are equal weight.  Note the fist argument must by
              an image variable (ex: i1, i2,....in).

       conv(index, rows, cols, <row ordered list of values> )

       this allows you to define an arbitrary matrix.
              The

       <row ordered list of values> is a comma separated
              list of constant values.

       assign_band(image_data, num1, data2, num2)

       will take band num2 from image data2 and assign it to
              band num1 in data 1.

       assign_band(image_data, num1, data2)

       will take band 1 from image data2 and assign it to
              band num1 in data 1.

       assign_band(image_data, num1, num2)

              will assin to band num1 of data 1 the value of num2

       x1 * x2                will multiply x1 and x2 x1 + x2                will add x1  and  x2
       x1  -  x2                will subtract x1 and x2 x1 / x2                will divide x1 and
       x2 x1 ^ x2                will do a power, raises x1 to x2 x1 | x2                will  do
       a bitwise or operation

              ( will do it in unisgned char precision)

       x1 & x2                will do a bitwise and operation

              ( will do it in unsigned char precision)

       ~x1                    will do the ones complement of the input

       x1 xor x2              will do an xclusive or operation

              (will do it in unsigned char precision)

       - x1                   will negative of x1

       Boolean ops: 1=true, 0=false x1 > x2 x1 >= x2 x1 == x2 x1 <= x2 x1 < x2 x1 <> x2

       Note:

       Currently an image input is reference by the variable in[<I>] where <I> is the input image
       index beginning at 0.  So 1 referes to the second image in the input list.

       (in[0] + in[1])/2 Will take image 1 and add it to image 2 and average them.

       exp(sqrt(in[0])/4) Will take the root of the image and divide by 4 and  then  raise  e  to
       that amount.

       128 Will return a constant value of 128 for all input bands.

       min(1,in[2],in[3], max(in[1],in[0]))

       shift(0, 1, 1) - i1 Will shift input 0 by 1 pixel along the diagonal  and then subtract it
       from input 1.

       assign_band(in[0], 1, blurr(in[0], 5, 5), 2) Will assign to the first band of i1  the  2nd
       band of the 5x5 blurr of i1.

       conv(0,  3, 3, -1, -2, -1, 0, 0, 0, 1, 2, 1) Will convolve the first input connection with
       a 3x3 matrix.  The args are row ordered:

       -1, -2, -1
              0,  0,  0 1,  2,  1

       NDVI: N=(in[0]-in[1])/(in[0]+in[1])

       For indexed-type values,like NDVI, (with limited values) it is better to  rescale  between
       0.0 and 1.0 and use type NormalizedFloat.

       Rescaled NDVI between 0 and 1: (N+1)/2 = in[0]/(in[0]+in[1])

SEE ALSO

       The  full documentation for ossim-equation is maintained as a Texinfo manual.  If the info
       and ossim-equation programs are properly installed at your site, the command

              info ossim-equation

       should give you access to the complete manual.