Extract Categorical Map Attributes

Description

Calculates basic statistics from a map for each class delimited by a categorical map, returning them as a table indexed jointly by attribute and class. All layers of the map are analyzed together, and the resulting table refers to them jointly.

Inputs

Name	Type	Description
Map	Map Type	Map whose attributes will be extracted.
Categorical Map	Categorical Map Type	Map of classes used to delimit the calculation area for each class in Map.

Optional Inputs

Name	Type	Description	Default Value
Extract Statistical Attributes	Boolean Value Type	If true, statistical attributes (mean, variance, standard deviation, mode, median, unique count) are also extracted.	Yes

Outputs

Name	Type	Description
Attributes	Table Type	Table of extracted attributes, keyed by attribute and by class.

Group

Map Algebra

Notes

Attributes has columns “Attribute” (key, the attribute's numeric code) and “Category” (key, the class value from Categorical Map), with the corresponding statistic in the “Value” data column.

Each attribute has a predefined name that can be used to retrieve it by name (rather than by numeric key) in Calculate Map, Calculate Categorical Map, Calculate Value, and the lookup table calculators.

If an attribute cannot be determined for a class, its entry is omitted from Attributes rather than being filled with a placeholder. Minimum and maximum values are only determined when the class has at least one non-null cell.

Dynamic attributes, computed across all non-null cells of all layers within each class:

Key	Predefined Name	Description
8	“nullCells”	number of null cells
9	“nonNullCells”	number of non-null cells
10	“minCell”	minimum value (excluding null cells)
11	“maxCell”	maximum value (excluding null cells)
12	“cellSum”	sum of the values (excluding null cells)

Statistical attributes (present only when Extract Statistical Attributes is true), computed across all non-null cells of all layers within each class:

Key	Predefined Name	Description
13	“meanCell”	average (excluding null cells)
14	“cellVar”	variance (excluding null cells)
15	“cellStd”	standard deviation (excluding null cells)
16	“modeCell”	mode (excluding null cells)
17	“medianCell”	median (excluding null cells)
18	“uniqueCells”	total unique occurrences (excluding null cells)

Internal Name

ExtractCategoricalMapAttributes