The Aggregation Algorithms

AVG

AggregatorAverage : This aggregator implements a weighted averaging with per overflight weighting as described in the referring NASA publication listed in the overview section. This aggregation method is well suited for satellite data acquired in the visible and NIR by integrating over the pixel area. It offers three parameters:

Weight coefficient: the weighting coefficient (float). A value of 0.0 disables weighting, default value is 1.0
Output counts: if selected, the measurement counts per bin-cell are stored in the output
Output sums: if selected, the measurement value sums per bin-cell are stored in the output instead of mean values. This feature allows a continuous aggregation of data over a longer period when not all input data is available at once.

Output bands are:

xxx_mean: the weighted mean value
xxx_sigma: the weighted standard deviation
xxx_counts: the measurement counts (optional)

If Output sums is selected:

xxx_sum: the weighted sum of the input measurements
xxx_sum_sq: the weighted sum of the squares of the input measurements
xxx_weights: the aggregated weights
xxx_counts: the measurement counts (optional)

AVG_OUTLIER

AggregatorAverageOutlierAware : implements an "outlier aware" averaging. It realises this by first calculating a mean and standard-deviation for the complete set of input measurements. Then the algorithm removes all measurements that are more than n standard deviations away from the mean value, where n is the so called "deviation factor". The remaining data is averaged using an unweighted version of the standard "AVG" aggregation described above. Parameters:

Deviation Factor: the deviation factor (float). Defines the distance to the mean value beyond which data is considered as outlier, distance = deviationFactor * standardDeviation. Default value is 1.0

Output bands are:

xxx_mean: the weighted mean value
xxx_sigma: the weighted standard deviation
xxx_counts: the measurement counts

MEAN_OBS

AggregatorMeanObs : calculates the standard, unweighted mean and standard deviation using all input measurements per cell. This aggregation method is suited for input data consisting of discrete measurements, e.g. number of detected fires. The aggregator has no public parameters.
Output bands are:

xxx_mean: the mean value
xxx_sigma: the standard deviation
xxx_counts: the measurement counts

MIN_MAX

AggregatorMinMax : an aggregator tracking the minimum and maximum value of the measurements over the binning period. This algorithm can be used to detect data ranges. The aggregator has no public parameters.
Output bands are:

xxx_min: the smallest value in the grid cell
xxx_max: the largest value in the grid cell

ON_MAX_SET

AggregatorOnMaxSet : this aggregator selects input data from a list of input variables under the condition that another band has the maximum value in the aggregation input set. For example it allows aggregating the output of all radiance data under the condition that the sensor-zenith angle is maximal. A tracking for a minimal value condition is possible by defining a virtual variable that contains the negative of the variable to be tracked. Parameters are:

Maximum Band Name: selects the band that is tracked for the maximal value
Source band Names: select a list of input band names. The values of these bands are written to the output if the Maximum Band has the peak value

Output bands are:

xxx_max: the largest value of the Maximum Bandin the input data
xxx_mjd: the Modified Julian Day value of the maximm value measurement
source_bands: all source band values defined in the parameter Source band Names

PERCENTILE

AggregatorPercentile : an aggregator that computes the p-th percentile, i.e. the value of a variable below which a certain percent (p) of observations fall. Parameters are:

Percentile: the precentile value (integer). Value must be between 0 and 100, default is 90.

Output bands are:

xxx_p: the percentile value of the input data

SUM

AggregatorSum : this aggregator sums up all input measurements per grid cell. It has no public parameters.
Output bands are:

xxx_sum: the sum of the input data