Extract Map Attributes

Description

This functor extracts the attributes and calculates basic statistics from a map and as a result creates a table that contains the extracted attributes.

Inputs

Name	Type	Description
Map	Map Type	Map whose attributes will be extracted.

Optional Inputs

Name	Type	Description	Default Value
Extract Dynamic Attributes	Boolean Value Type	If true, the dynamic attributes will be calculated.	True
Extract Statistical Attributes	Boolean Value Type	If true, statistical attributes will be calculated.	True

Outputs

Name	Type	Description
Attributes	Lookup Table Type	Table containing the attributes extracted from a map.
Layer Attributes	Table Type	Table containing the layer attributes.

Group

Map Algebra

Notes

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

The functor employs a lookup table with keys to the attributes. Each key 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 lookup 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.

Basic Attributes

Key	Predefined Name	Description
1	“lines”	number of lines
2	“columns”	number of columns
3	“cells”	number of cells (number of lines multiplied by the number of columns)
4	“layers”	number of layers
5	“cellHeight”	cell height (in meters)
6	“cellWidth”	cell width (in meters)
7	“cellArea”	cell area (in hectares)
19	“cellType”	cell type code
20	“nullValue”	null value
21	“registrationCoordinateY”	registration coordinate Y (this is the coordinate of the top left corner of the registered cell)
22	“registrationCoordinateX”	registration coordinate X (this is the coordinate of the top left corner of the registered cell)
23	“registrationCellY”	coordinate of registration cell Y
24	“registrationCellX”	coordinate of registration cell X
25	“rotationY”	rotation around Y
26	“rotationX”	rotation around X
27	“originalCellHeight”	cell height (cell height from projection - the unit is projection dependent)
28	“originalCellWidth”	cell width (cell height from projection - the unit is projection dependent)

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)

Cell Type Codes

The codes used to represent all the possible cells types, corresponding to attribute key 19 (“cellType”), are listed below. It is possible to convert the corresponding code back into a Cell Type.

Key	Cell Type
0	Unsigned 1 Bit Integer
1	Signed 8 Bit Integer
2	Unsigned 8 Bit Integer
3	Signed 16 Bit Integer
4	Unsigned 16 Bit Integer
5	Signed 32 Bit Integer
6	Unsigned 32 Bit Integer
7	IEEE 754 32 Bit Real
8	IEEE 754 64 Bit Real

Layer Attributes

The layer attributes1) Currently, only the layer name is the only layer specific attribute returned. are returned in a second table. This table has the following format.

Column Name	Key or Data?	Column Type	Description
“Layer_Index”	Key	Real	The index of the corresponding layer
“Layer_Name”	Key	String	The name of the corresponding layer

Internal Name

ExtractMapAttributes

Usage examples

See practical examples of this functor in Lesson 6: Extracting map attributes and basic statistics