Statistics function

The Statistics function calculates focal statistics for each pixel of an image based on a defined focal neighborhood.

The inputs for this function are the following:

There are four types of focal statistical functions:

The Neighborhood Settings allow you to enter the number of pixel rows and columns to use as your neighborhood dimensions.

The Fill NoData pixel values only check box can be checked when using this function to fill in gaps in the data, such as dropped lines.

The table below provides examples of the types using two different neighborhood dimensions based on the following image:

Unfiltered image


3x3 Neighborhood

5x5 Neighborhood


Min 3x3

Min 5x5


Max 3x3

Max 5x5


Mean 3x3

Mean 5x5

Standard Deviation

Std 3x3

Std 5x5

Focal statistical functions

Filling dropped lines

The Statistics function can be used to fill dropped lines in an image. Dropped lines are often caused by problems in the sensor where data is not collected. This has happened in sensors such as Landsat 7's Enhanced Thematic Mapper Plus (ETM+). This missing data causes problems for analysis and also when looking at the imagery. There is little that can be done when using the imagery for analysis; however, if there was an overlapping image, it could be used in place of the missing content. The same could be done if the imagery is being used for visualization. However, there isn't always an extra image to fill in the missing content, so it must be derived from the existing data.

This process requires two functions. First, insert the Mask function to convert the dropped line pixel values to NoData. For example, if the values are 0, then on the Mask function type 0 for each band in the NoData Values column. Next, insert the Statistics function. Use the Mean type, define the number of rows and columns to use for the neighborhood, and check Fill NoData pixel values only.

Dropped lines
Dropped lines
Filled dropped lines
Filled dropped lines

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