Block Statistics, Filter and Focal Flow Tools
Block Statistics
How to use Block Statistics
Tool in Arc Toolbox??
Block Statistics
Path to access the tool
:
Block
Statistics Tool, Neighborhood Toolset, Spatial Analyst Tools Toolbox
Block Statistics
Partitions the input
into non-overlapping blocks and calculates the statistic of the values within
each block. The value is assigned to all of the cells in each block in the
output.
1. Input raster
The raster on which to
perform the block statistics calculations.
2. Output raster
The output block
statistics raster.
3. Neighborhood (optional)
Specifies the shape of
the area around each cell used to calculate the statistic.
Once the neighborhood type is selected, other parameters can be set to define the shape of that neighborhood, the size, and the units.
- Annulus Inner radius Outer radius Units
A torus (donut-shaped) neighborhood defined by an inner radius and an outer radius. The default annulus is an inner radius of one cell and an outer radius of three cells.
- Circle Radius Units
A circular neighborhood with the given radius. The default radius is three cells.
- Rectangle Height Width Units
A rectangular neighborhood defined by the height and width. The default is a square with a height and width of three cells.
- Wedge Radius Start angle End angle Units
A wedge-shaped neighborhood defined by a radius, the start angle, and the end angle. The wedge extends counterclockwise from the starting angle to the ending angle. Angles are specified in degrees, with 0 or 360 representing east. Negative angles can be used. The default wedge is from 0 to 90 degrees, with a radius of 3 cells.
- Irregular Kernel file
A custom neighborhood with specifications set by a user-defined file.
- Weight Kernel file
A custom neighborhood with specifications set by a user-defined file, which can apply weights to the members of the neighborhood.
The distance units for
the parameters can be specified in cell units or map units. Cell units is the
default.
The default neighborhood
is a square rectangle with a width and height of three cells.
4. Statistics type (optional)
Specifies the statistic type to be calculated.
- MEAN—Calculates the mean (average value) of the cells in the neighborhood.
- MAJORITY—Calculates the majority (value that occurs most often) of the cells in the neighborhood.
- MAXIMUM—Calculates the maximum (largest value) of the cells in the neighborhood.
- MEDIAN—Calculates the median of the cells in the neighborhood.
- MINIMUM—Calculates the minimum (smallest value) of the cells in the neighborhood.
- MINORITY—Calculates the minority (value that occurs least often) of the cells in the neighborhood.
- RANGE—Calculates the range (difference between largest and smallest value) of the cells in the neighborhood.
- STD—Calculates the standard deviation of the cells in the neighborhood.
- SUM—Calculates the sum (total of all values) of the cells in the neighborhood.
- VARIETY—Calculates the variety (the number of unique values) of the cells in the neighborhood.
The default statistic
type is MEAN.
5. Ignore NoData in calculations (optional)
Specifies whether NoData values will be ignored by the statistic calculation.
- Checked—If a NoData value exists within a block neighborhood, the NoData value will be ignored. Only cells within the neighborhood that have data values will be used in determining the output value. This is the default.
- Unchecked—If any cell in a neighborhood has a value of NoData, the output for each cell in the corresponding block will be NoData. If this parameter is not checked, the presence of a NoData value implies that there is insufficient information to determine the statistic value for the neighborhood.
Filter
How to use Filter Tool in Arc Toolbox??
Filter Tool
Path to access the tool
:
Filter Tool, Neighborhood Toolset, Spatial Analyst Tools Toolbox
Filter
Performs either a
smoothing (Low pass) or edge-enhancing (High pass) filter on a raster.
1. Input raster
The input raster on
which to perform the filter operation.
2. Output raster
The output filtered
raster.
The output is always
floating point.
3. Filter type (optional)
The type of filter operation to perform.
- LOW—Traverses a low pass 3-by-3 filter over the raster. This option smooths the entire input raster and reduces the significance of anomalous cells.This is the default.
- HIGH—Traverses a high pass 3-by-3 filter over the raster. This option enhances the edges of subdued features in a raster.
4. Ignore NoData in calculations (optional)
Denotes whether NoData values are ignored by the filter calculation.
- Checked—If a NoData value exists within the filter, the NoData value will be ignored. Only cells within the filter that have data values will be used in determining the output.
- Unchecked—If a NoData value exists within the filter, the output for the processing cell will be NoData. With this option, the presence of a NoData value implies that there is insufficient information to determine the statistic value for the neighborhood.
Focal Flow
How to use Focal Flow Tool in Arc Toolbox??
Focal Flow
Path to access the tool
:
Focal
Flow Tool, Neighborhood Toolset, Spatial Analyst Tools Toolbox
Focal Flow
Determines the flow of
the values in the input raster within each cell's immediate neighborhood.
1. Input surface raster
The input surface raster
for which to calculate the focal flow.
The eight immediate
neighbors of each cell are evaluated to determine the flow.
The input raster can be
integer or floating point.
2. Output raster
The output focal flow
raster.
The output raster is
always of integer type.
3. Threshold value (optional)
Defines a value that
constitutes the threshold, which must be equaled or exceeded before flow can
occur.
The threshold value can
be either an integer or floating-point value.
If the difference between the value at a neighboring cell location and the value of the processing cell is less than or equal to the threshold value, the output will be 0 (or no flow).
Comments
Post a Comment