====== Extract Categorical Map Attributes =====

===== Description =====

This functor calculates basic statistics from a map for each area delimited by a class. The result is returned in a table contains the extracted classes and their corresponding attributes.

===== Inputs =====

^ Name  ^ Type  ^ Description  ^
| Map  | [[Map Type]]  | Map whose attributes will be extracted.  |
| Categorical Map  | [[Categorical Map Type]]  | Map whose classes will be used to delimit the calculation areas in the input.  |

===== Optional Inputs =====

^ Name  ^ Type  ^ Description  ^ Default Value  ^
| Extract Statistical Attributes  | [[Boolean Value Type]]  | If true, [[Extract Map Attributes#Statistical attributes|statistical attributes]] will be calculated. | True  |

===== Outputs =====

^ Name  ^ Type  ^ Description  ^
| Attributes | [[Table Type]]  | Table containing the attributes extracted from a map. |

===== Group =====

[[Functor List#Map Algebra | Map Algebra]]

===== Notes =====

This functor analyzes all map layers. The resulting table refers to all of them.

The functor returns a table mapping classes and attributes to their corresponding attribute value. This table has the following format.

^ Column Name  ^ Key or Data?  ^ Column Type  ^ Description  ^
| "Attribute"  | Key  | Real  | The attribute key  |
| "Category"  | Key  | Real  | The map category  |
| "Value"  | Data  | Real  | The attribute from the map  |

Each "Attribute" has a predefined name. This name can be used to retrieve the corresponding attribute in [[Calculate Map]], [[Calculate Categorical Map]], [[Calculate Value]] and [[Calculate Lookup Table]].

If it is not possible to determine any of these attributes, the corresponding entry in the output table is left blank. It determines the maximum and the minimum values only when there is at least one non null cell on the map for the given class.

==== Dynamic attributes ====

^ 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 ====

^ 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