Focal, Line and Point Statistics Tools
Focal Statistics
How to use Focal Statistics Tool in Arc Toolbox??
Focal Statistics
Path to access the tool
:
Focal
Statistics Tool, Neighborhood Toolset, Spatial
Analyst Tools Toolbox
Focal Statistics
Calculates for each
input cell location a statistic of the values within a specified neighborhood
around it.
1. Input raster
The raster on which the
focal statistics will be calculated.
2. Output raster
The output focal
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.
- PERCENTILE—Calculates a percentile of the cells in the neighborhood. The 90th percentile is calculated by default. You can specify other values (from 0 to 100) using the Percentile value parameter.
- 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.
If the input raster is
integer, all the statistics types are available. If the input raster is
floating point, only the MEAN, MAXIMUM, MEDIAN, MINIMUM, PERCENTILE, RANGE,
STD, and SUM statistic types are available.
5. Percentile value (optional)
The percentile to
calculate. The default is 90, for the 90th percentile.
The values can range
from 0 to 100. The 0th percentile is essentially equivalent to the Minimum
statistic, and the 100th percentile is equivalent to Maximum. A value of 50
will produce essentially the same result as the Median statistic.
This option is only
available if the Statistics type parameter is set to Percentile.
6. Ignore NoData in calculations (optional)
Specifies whether NoData values will be ignored by the statistic calculation.
- Checked—If a NoData value exists within a 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 means that if the processing cell value is NoData, the processing cell may receive a value in the output raster if this parameter is checked, provided at least one cell within the neighborhood has a valid value. This is the default.
- Unchecked—If any cell in a neighborhood has a value of NoData, including the processing cell, the output for the processing cell 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.
Line Statistics
How to use Line Statistics Tool in Arc Toolbox??
Line Statistics
Path to access the tool
:
Line
Statistics Tool, Neighborhood Toolset, Spatial
Analyst Tools Toolbox
Line Statistics
Calculates a statistic
on the attributes of lines in a circular neighborhood around each output cell.
1. Input polyline features
The input polyline
features for which to calculate the statistics in a neighbourhood around each
output cell.
2. Field
The field that the
specified statistic will be calculated for. It can be any numeric field of the
input features.
When the statistics type
is set to LENGTH, the Field can be set to None.
It can be the Shape
field if the input features contain z-values.
3. Output raster
The output line
statistics raster.
4. Output cell size (optional)
The cell size of the output
raster that will be created.
This parameter can be
defined by a numeric value or obtained from an existing raster dataset. If the
cell size hasn't been explicitly specified as the parameter value, the
environment cell size value will be used if specified; otherwise, additional
rules will be used to calculate it from the other inputs. See the usage for
more detail.
5. Search radius (optional)
Search radius to
calculate the desired statistic within, in map units.
The default radius is
five times the output cell size.
6. Statistics type (optional)
Specifies the statistic
type to be calculated.
Statistics are calculated on the value of the specified field for all lines within the neighborhood.
- MEAN—Calculates the average field value in each neighborhood, weighted by the length.The form of the calculation is:
Mean = (sum of (length * field_value)) /
(sum_of_length)
Only the part of the length that falls within the neighborhood is used.
- MAJORITY—Determines the value having the greatest length of line in the neighborhood.
- MAXIMUM—Determines the largest value in the neighborhood.
- MEDIAN—Determines the median value, weighted by the length.Conceptually, all line segments in the neighborhood are sorted by value and placed end-to-end in a straight line. The value of the segment at the midpoint of the straight line is the median.
- MINIMUM—Calculates smallest value in each neighborhood.
- MINORITY—The value having the least length of line in the neighborhood.
- RANGE—The range of values (maximum–minimum).
- VARIETY—The number of unique values.
- LENGTH—The total line length in the neighborhood. If the value of the field is other than 1, the lengths are multiplied by the item value before adding them together. This option can be used when the Field is set to None.
When the specified field
is integer, the available statistic choices are Mean, Majority, Maximum,
Median, Minimum, Minority, Range, and Variety. When the field is floating
point, the only allowed statistics are Mean,
Maximum, Minimum, and Range.
Point Statistics
How to use Point Statistics Tool in Arc Toolbox??
Point Statistics
Path to access the tool
:
Point
Statistics Tool, Neighborhood Toolset, Spatial
Analyst Tools Toolbox
Point Statistics
Calculates a statistic
on the points in a neighborhood around each output cell.
1. Input point features
The input point features
for which to calculate the statistics in a neighborhood around each output
cell.
The input can be either
a point or multipoint feature class.
2. Field
The field that the
specified statistic will be calculated for. It can be any numeric field of the
input features.
It can be the Shape
field if the input features contain z-values.
3. Output raster
The output point
statistics raster.
4. Output cell size (optional)
The cell size of the
output raster that will be created.
This parameter can be
defined by a numeric value or obtained from an existing raster dataset. If the
cell size hasn't been explicitly specified as the parameter value, the
environment cell size value will be used if specified; otherwise, additional
rules will be used to calculate it from the other inputs. See the usage for
more detail.
5. Neighborhood (optional)
Dictates the shape of
the area around each input point location used to calculate the statistic.
The parameters and descriptions for each of the neighborhood types follow.
- Annulus Inner radius Outer radius Units
- Circle Radius Units
- Rectangle Height Width Units
- 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.
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.
6. Statistics type (optional)
Specifies the statistic
type to be calculated.
The calculation is
performed on the values of the specified field of the point input in the
neighborhood of each output raster cell.
- 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.
- PERCENTILE—Calculates a percentile of the cells in the neighborhood. The 90th percentile is calculated by default. You can specify other values (from 0 to 100) using the Percentile value parameter.
- 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 available choices for the statistics type is determined by the numeric type of the specified field.
Comments
Post a Comment