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.