sgs::helper::Variance

#include <helper.h>

Public Member Functions
void	update (double x)
double	getMean ()
double	getStdev ()
int64_t	getCount ()

Detailed Description

This struct contains the intermediate values, as well as functions for updating the intermediate values of the variance of a raster band using Welfords method. The mean and standard deviation of a raster band can be calculated afterwards without requiring the whole raster to be in memory.

Double precision is always used for higher precision of potentially small values.

https://jonisalonen.com/2013/deriving-welfords-method-for-computing-variance/

Member Function Documentation

getCount()

int64_t sgs::helper::Variance::getCount ( )

inline

calculate the total number of pixels.

Returns

itn64_t

getMean()

double sgs::helper::Variance::getMean ( )

inline

getter function for running mean value.

Returns

double

getStdev()

double sgs::helper::Variance::getStdev ( )

inline

calculate the standard deviation using the running variance calculation.

Returns

double

update()

void sgs::helper::Variance::update ( double x )

inline

update the variance calculation with a new value.

Parameters

double

x

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The documentation for this class was generated from the following file:

• sgspy/utils/helper.h