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-<h2>DESCRIPTION</h2>
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-
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-<em>r.mfilter.fp</em> filters the raster <em>input</em> to produce the
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-raster <em>output</em> according to the matrix <em>filter</em> designed
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-by the user (see <em>FILTERS</em> below).
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-The filter is applied <em>repeat</em> times (default <em>value</em> is 1).
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-The <em>output</em> raster map layer can be given a <em>TITLE</em> if desired.
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-(This TITLE should be put in quotes if it contains more than one word.)
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-
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-With <b>-z</b> flag the filter is applied only to null values in
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-the input raster map layer. The non-null category values are not changed.
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-Note that if there is more than one filter step, this rule is applied to the
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-intermediate raster map layer -- only null category values which result from
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-the first filter will be changed. In most cases this will NOT be the
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-desired result. Hence -z should be used only with single step filters.
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-<p>
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-
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-The <b>filter</b> parameter defines the name of an existing, user-created
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-UNIX ASCII file whose contents is a matrix defining the way in which the
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-<em>input</em> file will be filtered. The format of this file is described
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-below, under FILTERS.
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-<p>
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-
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-The <b>repeat</b> parameter defines the number of times the <em>filter</em>
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-is to be applied to the <em>input</em> data.
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-
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-<h2>FILTERS</h2>
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-
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-The <em>filter</em> file is a normal UNIX ASCII file designed by the user.
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-It has the following format:
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-<pre>
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- TITLE TITLE
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- MATRIX n
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- .
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- n lines of n values
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- .
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- DIVISOR d
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- TYPE S/P
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-</pre>
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-
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-<dl>
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-<dt>TITLE
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-
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-<dd>A one-line TITLE for the filter.
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-If a TITLE was not specified on the command line, it can be specified here.
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-This TITLE would be used to construct a TITLE for the resulting raster map
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-layer. It should be a one-line description of the filter.
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-
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-<dt>MATRIX
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-
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-<dd>The matrix (n x n) follows on the next n lines. <em>n</em> must be
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-an odd integer greater than or equal to 3.
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-The matrix itself consists of n rows of n values.
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-The values must be separated from each other by at least 1 blank.
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-
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-<dt>DIVISOR
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-
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-<dd>The filter divisor is <em>d</em>. If not specified, the default is 1.
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-If the divisor is zero (0), then the divisor is dependent on the
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-category values in the neighborhood
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-(see HOW THE FILTER WORKS below).
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-
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-<dt>TYPE
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-
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-<dd>The filter type. <em>S</em> means sequential, while <em>P</em> mean parallel.
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-If not specified, the default is S.
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-
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-
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-<p>
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-
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-Sequential filtering happens in place. As the filter is applied to the
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-raster map layer, the category values that were changed in neighboring
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-cells affect the resulting category value of the current
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-cell being filtered.
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-
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-
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-<p>
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-Parallel filtering happens in such a way that the original raster
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-map layer category values are used to produce the new category value.
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-
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-
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-<p>
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-More than one filter may be specified in the filter file.
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-The additional filter(s) are described just like the first.
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-For example, the following describes two filters:
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-</p>
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-
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-</dl>
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-
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-
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-<h2>EXAMPLE FILTER FILE</h2>
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-
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-<pre>
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- TITLE 3x3 average, non-null data only, followed by 5x5 average
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- MATRIX 3
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- 1 1 1
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- 1 1 1
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- 1 1 1
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- DIVISOR 0
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- TYPE P
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-
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- MATRIX 5
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- 1 1 1 1 1
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- 1 1 1 1 1
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- 1 1 1 1 1
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- 1 1 1 1 1
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- 1 1 1 1 1
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- DIVISOR 25
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- TYPE P
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-</pre>
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-
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-<h2>HOW THE FILTER WORKS</h2>
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-
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-The filter process produces a new category value for each cell
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-in the input raster map layer by multiplying the category values of the
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-cells in the n x n neighborhood around the center cell
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-by the corresponding matrix value and adding them together.
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-If a divisor is specified, the sum is divided by this divisor.
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-(If a zero divisor was specified, then
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-the divisor is computed for each cell as the sum of the MATRIX
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-values where the corresponding input cell is non-null.)
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-
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-
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-<p>
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-
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-If more than one filter step is specified, either because the
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-repeat value was greater than one or because the filter file
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-contained more than one matrix, these steps are performed
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-sequentially. This means that first one filter is applied to
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-the entire input raster map layer to produce an intermediate result;
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-then the next filter is applied to the intermediate result to
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-produce another intermediate result; and so on, until the
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-final filter is applied. Then the output cell is written.
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-
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-<h2>NOTES</h2>
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-
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-If the resolution of the geographic region does not agree with the
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-resolution of the raster map layer, unintended resampling of the original
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-data may occur. The user should be sure that the geographic region
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-is set properly.
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-
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-<h2>SEE ALSO</h2>
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-
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-<em><a href="g.region.html">g.region</a></em>,
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-<em><a href="r.clump.html">r.clump</a></em>,
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-<em><a href="r.neighbors.html">r.neighbors</a></em>
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-<em><a href="r.mfilter.html">r.mfilter</a></em>
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-
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-<h2>AUTHOR</h2>
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-
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-Glynn Clements.
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-Based upon r.mfilter, by Michael Shapiro,
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-U.S.Army Construction Engineering Research Laboratory
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-
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-<p>
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-<i>Last changed: $Date$</i>
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